[{"Name":"Monosaccharides and Disaccharides","TopicPlaylistFirstVideoID":0,"Duration":null,"Videos":[{"Watched":false,"Name":"Intro to Carbohydrates Part 1","Duration":"8m 1s","ChapterTopicVideoID":28926,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:03.135","Text":"Welcome to the chapter on carbohydrates,"},{"Start":"00:03.135 ","End":"00:06.545","Text":"and we\u0027re going to start with talking about simple carbohydrates,"},{"Start":"00:06.545 ","End":"00:09.660","Text":"and this lesson is an introduction to carbohydrates."},{"Start":"00:09.660 ","End":"00:13.845","Text":"In this section, we will learn about the role of carbohydrates in living things,"},{"Start":"00:13.845 ","End":"00:17.490","Text":"carbohydrate classification, and list common monosaccharides,"},{"Start":"00:17.490 ","End":"00:20.445","Text":"disaccharides, and polysaccharides."},{"Start":"00:20.445 ","End":"00:22.590","Text":"Let\u0027s split this into 2 parts."},{"Start":"00:22.590 ","End":"00:24.480","Text":"We will start with part I,"},{"Start":"00:24.480 ","End":"00:27.090","Text":"where we will focus on the role of carbohydrates in living things."},{"Start":"00:27.090 ","End":"00:32.055","Text":"The carbohydrate general structure and formula and carbohydrate classification."},{"Start":"00:32.055 ","End":"00:36.585","Text":"Carbohydrates are the most abundant biomolecules on Earth."},{"Start":"00:36.585 ","End":"00:39.330","Text":"Each year, photosynthesis converts"},{"Start":"00:39.330 ","End":"00:44.330","Text":"more than 100 billion metric tons of CO_2"},{"Start":"00:44.330 ","End":"00:49.400","Text":"and H_2O carbon dioxide and water into cellulose,"},{"Start":"00:49.400 ","End":"00:52.595","Text":"a polysaccharide, and other plant products,"},{"Start":"00:52.595 ","End":"00:55.375","Text":"which are forms of carbohydrates."},{"Start":"00:55.375 ","End":"00:59.450","Text":"As you see here, this is composed of"},{"Start":"00:59.450 ","End":"01:05.135","Text":"cellulose as its main structural carbohydrate product."},{"Start":"01:05.135 ","End":"01:08.330","Text":"Certain carbohydrates, sugar and starch,"},{"Start":"01:08.330 ","End":"01:11.930","Text":"are a dietary staple in most parts of the world and we will expand"},{"Start":"01:11.930 ","End":"01:15.560","Text":"on these a little later so what you see are carbohydrates,"},{"Start":"01:15.560 ","End":"01:22.785","Text":"this would be starch and you have sugars that compose fruit, corn, etc."},{"Start":"01:22.785 ","End":"01:24.800","Text":"The oxidation of carbohydrates is"},{"Start":"01:24.800 ","End":"01:29.420","Text":"the central energy-yielding pathway and most non-photosynthetic cells."},{"Start":"01:29.420 ","End":"01:32.705","Text":"We early on talked about how cell function relies on"},{"Start":"01:32.705 ","End":"01:36.970","Text":"energy and organism and livelihood depends on energy."},{"Start":"01:36.970 ","End":"01:43.295","Text":"We need to have this ability to utilize metabolize energy and actually"},{"Start":"01:43.295 ","End":"01:49.970","Text":"to gain it from our surrounding and to store it and it is the oxidation of carbohydrates,"},{"Start":"01:49.970 ","End":"01:52.190","Text":"this process that is"},{"Start":"01:52.190 ","End":"01:59.960","Text":"the most common energy-yielding pathway in most cells that are non-photosynthetic,"},{"Start":"01:59.960 ","End":"02:05.110","Text":"as well as many photosynthetic cells where this occurs alongside photosynthesis."},{"Start":"02:05.110 ","End":"02:07.910","Text":"Insoluble carbohydrate polymers serve as"},{"Start":"02:07.910 ","End":"02:11.090","Text":"structural and protective elements in the cell walls of"},{"Start":"02:11.090 ","End":"02:14.900","Text":"bacteria and plants and in the connective tissues of animals."},{"Start":"02:14.900 ","End":"02:16.250","Text":"You see a plant cell,"},{"Start":"02:16.250 ","End":"02:18.515","Text":"there is a cell wall,"},{"Start":"02:18.515 ","End":"02:19.775","Text":"it\u0027s made of cellulose,"},{"Start":"02:19.775 ","End":"02:21.140","Text":"as we saw in an earlier figure."},{"Start":"02:21.140 ","End":"02:24.470","Text":"In this figure, you see an example of cellulose where it is"},{"Start":"02:24.470 ","End":"02:28.310","Text":"what makes up the structural wall of the plant cell"},{"Start":"02:28.310 ","End":"02:37.160","Text":"and chains of cellulose these carbohydrates make up what composes and creates the plants."},{"Start":"02:37.160 ","End":"02:41.630","Text":"Other carbohydrate polymers lubricate skeletal joints"},{"Start":"02:41.630 ","End":"02:45.920","Text":"and participate in recognition and adhesion between cells."},{"Start":"02:45.920 ","End":"02:49.010","Text":"As I mentioned, there can be structural components of cells as"},{"Start":"02:49.010 ","End":"02:52.295","Text":"well as protective covering example chitin or chitin,"},{"Start":"02:52.295 ","End":"02:55.970","Text":"a fibrous substance consisting of polysaccharides and forming"},{"Start":"02:55.970 ","End":"03:01.655","Text":"the major constituent in the exoskeleton of arthropods in the cell walls of fungi,"},{"Start":"03:01.655 ","End":"03:03.260","Text":"like in this ladybug."},{"Start":"03:03.260 ","End":"03:08.285","Text":"A more pleasant example than others that ones as the cockroach, La Cucaracha,"},{"Start":"03:08.285 ","End":"03:14.435","Text":"this hard external exoskeleton is made of polysaccharides as well."},{"Start":"03:14.435 ","End":"03:18.890","Text":"More complex carbohydrate polymers covalently attached to proteins or lipids act"},{"Start":"03:18.890 ","End":"03:20.135","Text":"as signals that determine"},{"Start":"03:20.135 ","End":"03:24.050","Text":"the intracellular location or metabolic fate of"},{"Start":"03:24.050 ","End":"03:28.345","Text":"these hydro molecules called glycoconjugates."},{"Start":"03:28.345 ","End":"03:30.934","Text":"We will introduce the major classes of carbohydrates"},{"Start":"03:30.934 ","End":"03:33.485","Text":"and there are many structural and functional roles."},{"Start":"03:33.485 ","End":"03:38.075","Text":"Carbohydrates are polyhydroxy aldehyde or ketones."},{"Start":"03:38.075 ","End":"03:41.840","Text":"Polyhydroxy aldehydes or ketones are molecules with"},{"Start":"03:41.840 ","End":"03:46.025","Text":"more than 1 hydroxyl group and a carbonyl group,"},{"Start":"03:46.025 ","End":"03:48.065","Text":"either at the terminal carbon atom,"},{"Start":"03:48.065 ","End":"03:50.630","Text":"the aldose or at the second carbon atom,"},{"Start":"03:50.630 ","End":"03:53.570","Text":"a ketose and we\u0027ll go into these terms a little"},{"Start":"03:53.570 ","End":"03:56.705","Text":"further and these are called carbohydrates."},{"Start":"03:56.705 ","End":"04:00.365","Text":"Polyhydroxyl aldehydes are organic compounds containing"},{"Start":"04:00.365 ","End":"04:04.715","Text":"many hydroxyl groups and this aldehyde group well,"},{"Start":"04:04.715 ","End":"04:10.850","Text":"polyhydroxy ketone organic compounds containing many hydroxyl groups and a ketone group."},{"Start":"04:10.850 ","End":"04:13.460","Text":"The difference between the aldehyde group and"},{"Start":"04:13.460 ","End":"04:17.240","Text":"the ketone group is that the aldehyde group you\u0027ll have"},{"Start":"04:17.240 ","End":"04:24.035","Text":"a carbon bound to an oxygen as well the fourth bonded will be hydrogen."},{"Start":"04:24.035 ","End":"04:28.730","Text":"The ketone group will be a carbon double bond to the oxygen,"},{"Start":"04:28.730 ","End":"04:32.825","Text":"bound to another group since in the aldehyde,"},{"Start":"04:32.825 ","End":"04:35.810","Text":"it will be at the end."},{"Start":"04:35.810 ","End":"04:38.765","Text":"The hydroxyl group will be at the end,"},{"Start":"04:38.765 ","End":"04:40.220","Text":"the terminal carbon atom."},{"Start":"04:40.220 ","End":"04:45.950","Text":"Therefore, all 4 bonds need to be consumed here because the carbon can have 4 bonds,"},{"Start":"04:45.950 ","End":"04:50.497","Text":"all in total can have 4 bonds so you have 1, 2,"},{"Start":"04:50.497 ","End":"04:57.665","Text":"3, 4 while this in the case of the ketone because it\u0027s on the second carbon atom,"},{"Start":"04:57.665 ","End":"05:06.543","Text":"it needs to have an extra bond because it\u0027s part of a chain so 1,"},{"Start":"05:06.543 ","End":"05:11.855","Text":"2, 3, and 4, this is lightly another carbon that it\u0027s bound to."},{"Start":"05:11.855 ","End":"05:16.025","Text":"Now, both these compounds have carbonyl groups."},{"Start":"05:16.025 ","End":"05:20.540","Text":"In other words, we define polyhydroxy aldehyde or polyhydroxy"},{"Start":"05:20.540 ","End":"05:26.345","Text":"ketones as those carbon compounds in which the number of carbon atoms is high,"},{"Start":"05:26.345 ","End":"05:30.850","Text":"where more than 1 carbon atom has an alcohol or hydroxyl group."},{"Start":"05:30.850 ","End":"05:33.425","Text":"The terminal carbon has either the aldehyde,"},{"Start":"05:33.425 ","End":"05:37.970","Text":"which we will just write as CHO, or the ketone,"},{"Start":"05:37.970 ","End":"05:42.095","Text":"which we will write for short as a CO,"},{"Start":"05:42.095 ","End":"05:45.845","Text":"so either the aldehyde group or the ketone group,"},{"Start":"05:45.845 ","End":"05:50.510","Text":"or substances that yield such compounds on hydrolysis."},{"Start":"05:50.510 ","End":"05:53.030","Text":"Many, but not all carbohydrates have"},{"Start":"05:53.030 ","End":"05:58.565","Text":"the empirical formula CH_2O in parenthesis to the number n,"},{"Start":"05:58.565 ","End":"06:05.735","Text":"meaning that you have generally the ratio of carbon to oxygen,"},{"Start":"06:05.735 ","End":"06:07.535","Text":"which is 1 to 1,"},{"Start":"06:07.535 ","End":"06:13.800","Text":"and the ratio of carbon to hydrogen as 1 to"},{"Start":"06:13.800 ","End":"06:19.530","Text":"2 and hydrogen to oxygen 1 to 2 as well."},{"Start":"06:19.530 ","End":"06:22.310","Text":"It\u0027s 1 to 1 with regards to hydrogen versus carbon"},{"Start":"06:22.310 ","End":"06:25.355","Text":"and oxygen and carbon to oxygen are 1 to 1."},{"Start":"06:25.355 ","End":"06:29.074","Text":"Now we learned this in a previous lesson and other contexts but generally,"},{"Start":"06:29.074 ","End":"06:39.740","Text":"what this means is that you will have CHO and some configuration bound to oxygen"},{"Start":"06:39.740 ","End":"06:48.620","Text":"as well as to another carbon that will be bound similarly and it just means"},{"Start":"06:48.620 ","End":"06:53.330","Text":"that carbohydrates have this in repeating units"},{"Start":"06:53.330 ","End":"06:55.490","Text":"to end stands that there are multiple groups of"},{"Start":"06:55.490 ","End":"06:58.420","Text":"this and that\u0027s what makes the carbohydrates."},{"Start":"06:58.420 ","End":"07:01.370","Text":"Carbohydrates have this empirical formula."},{"Start":"07:01.370 ","End":"07:05.825","Text":"It\u0027s very common to see this a CH_2O, in parenthesis n,"},{"Start":"07:05.825 ","End":"07:09.395","Text":"in which n is bigger or equal to 3,"},{"Start":"07:09.395 ","End":"07:14.675","Text":"meaning there\u0027ll be at least 3 of this and that is what is termed a carbohydrate."},{"Start":"07:14.675 ","End":"07:17.120","Text":"It will have many carbon atoms."},{"Start":"07:17.120 ","End":"07:21.920","Text":"Now, this is also the source of the name carbohydrate"},{"Start":"07:21.920 ","End":"07:28.684","Text":"because you have carbon plus hydrate, hydrogen."},{"Start":"07:28.684 ","End":"07:31.625","Text":"Put this together and you have"},{"Start":"07:31.625 ","End":"07:38.550","Text":"carbohydrate representing the main composition of the molecule."},{"Start":"07:38.550 ","End":"07:42.380","Text":"With this, we completed part I of the introduction to carbohydrates,"},{"Start":"07:42.380 ","End":"07:44.840","Text":"specifically simple carbohydrates and we"},{"Start":"07:44.840 ","End":"07:47.510","Text":"covered the role of carbohydrates in living things,"},{"Start":"07:47.510 ","End":"07:49.670","Text":"which we will further talk about."},{"Start":"07:49.670 ","End":"07:52.325","Text":"Carbohydrate general structure and formula."},{"Start":"07:52.325 ","End":"07:57.425","Text":"We just completed this portion and carbohydrate classification,"},{"Start":"07:57.425 ","End":"08:01.890","Text":"where we are going to further talk about this in the next part."}],"ID":30476},{"Watched":false,"Name":"Intro to Carbohydrates Part 2","Duration":"7m 56s","ChapterTopicVideoID":28927,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.065","Text":"Welcome to Part 2 of the introduction to carbs,"},{"Start":"00:04.065 ","End":"00:07.350","Text":"specifically within simple carbohydrates."},{"Start":"00:07.350 ","End":"00:09.239","Text":"In this section, we\u0027re going to continue"},{"Start":"00:09.239 ","End":"00:11.760","Text":"talking about the role of carbohydrates in living things."},{"Start":"00:11.760 ","End":"00:14.415","Text":"We\u0027re going to talk about the carbohydrate classification"},{"Start":"00:14.415 ","End":"00:16.320","Text":"and list common monosaccharides,"},{"Start":"00:16.320 ","End":"00:18.450","Text":"disaccharides, and polysaccharides."},{"Start":"00:18.450 ","End":"00:22.770","Text":"Now we completed the first part talking about the molecule,"},{"Start":"00:22.770 ","End":"00:24.795","Text":"the structure of the formula, etc."},{"Start":"00:24.795 ","End":"00:28.740","Text":"At this point, we\u0027re now going to take a step back,"},{"Start":"00:28.740 ","End":"00:34.575","Text":"zoom out, and we are going to talk about the classification."},{"Start":"00:34.575 ","End":"00:38.430","Text":"There are 3 major size classes of carbohydrates."},{"Start":"00:38.430 ","End":"00:42.435","Text":"You have the monosaccharides, mono, 1."},{"Start":"00:42.435 ","End":"00:44.566","Text":"As you see here, glucose, fructose, and galactose,"},{"Start":"00:44.566 ","End":"00:46.985","Text":"these are all monosaccharides."},{"Start":"00:46.985 ","End":"00:50.075","Text":"You have oligosaccharides."},{"Start":"00:50.075 ","End":"00:53.060","Text":"These are when you have monosaccharides linked together by"},{"Start":"00:53.060 ","End":"00:56.695","Text":"condensation and you have multiple."},{"Start":"00:56.695 ","End":"01:00.080","Text":"Then you have the polysaccharide."},{"Start":"01:00.080 ","End":"01:02.990","Text":"Poly means many,"},{"Start":"01:02.990 ","End":"01:05.875","Text":"and mono is 1."},{"Start":"01:05.875 ","End":"01:08.390","Text":"Polysaccharides are monosaccharides linked"},{"Start":"01:08.390 ","End":"01:11.690","Text":"together by condensation to form this polysaccharide."},{"Start":"01:11.690 ","End":"01:13.760","Text":"It has many of these in the chain."},{"Start":"01:13.760 ","End":"01:15.800","Text":"You see examples of these starch,"},{"Start":"01:15.800 ","End":"01:19.430","Text":"glycogen, and cellulose which we mentioned earlier."},{"Start":"01:19.430 ","End":"01:22.295","Text":"A reminder, we mentioned this earlier,"},{"Start":"01:22.295 ","End":"01:24.380","Text":"not only the mono and the poly,"},{"Start":"01:24.380 ","End":"01:26.960","Text":"but the term saccharide,"},{"Start":"01:26.960 ","End":"01:30.920","Text":"that is derived from Greek, saccharine meaning sugar."},{"Start":"01:30.920 ","End":"01:35.990","Text":"Monosaccharide, 1 sugar molecule,"},{"Start":"01:35.990 ","End":"01:38.405","Text":"oligo, several, poly,"},{"Start":"01:38.405 ","End":"01:40.040","Text":"many sugar molecules in a chain."},{"Start":"01:40.040 ","End":"01:41.735","Text":"Let\u0027s elaborate on these."},{"Start":"01:41.735 ","End":"01:44.060","Text":"Monosaccharides are simple sugars."},{"Start":"01:44.060 ","End":"01:47.915","Text":"Consist of a single polyhydroxy aldehyde or ketone unit."},{"Start":"01:47.915 ","End":"01:54.650","Text":"The most abundant monosaccharide in nature is this 6-carbon sugar,"},{"Start":"01:54.650 ","End":"02:00.250","Text":"D-glucose also referred to as dextrose."},{"Start":"02:00.250 ","End":"02:03.870","Text":"What you see here is that molecule."},{"Start":"02:03.870 ","End":"02:05.690","Text":"Monosaccharides have more than 4 carbons,"},{"Start":"02:05.690 ","End":"02:07.445","Text":"tend to have cyclic structures."},{"Start":"02:07.445 ","End":"02:08.914","Text":"You see we have 1, 2,"},{"Start":"02:08.914 ","End":"02:10.400","Text":"3, 4, 5, 6."},{"Start":"02:10.400 ","End":"02:13.670","Text":"It can form this cyclic structure,"},{"Start":"02:13.670 ","End":"02:19.115","Text":"this ring, so it can be either linear or it can be in a ring."},{"Start":"02:19.115 ","End":"02:23.900","Text":"Oligosaccharides consist of short chains of monosaccharide units or residues"},{"Start":"02:23.900 ","End":"02:29.370","Text":"joined by characteristic linkages called glycosidic bonds."},{"Start":"02:29.370 ","End":"02:32.240","Text":"You see here what happens is they come"},{"Start":"02:32.240 ","End":"02:36.620","Text":"together and what happens you have an OH and some group."},{"Start":"02:36.620 ","End":"02:38.503","Text":"An OH and hydrogen,"},{"Start":"02:38.503 ","End":"02:47.165","Text":"they will come together to basically release 1 OH and will release 1 hydrogen,"},{"Start":"02:47.165 ","End":"02:54.020","Text":"and now both these molecules are combined and connected in 1 hydrogen,"},{"Start":"02:54.020 ","End":"02:56.300","Text":"so water is released."},{"Start":"02:56.300 ","End":"03:00.290","Text":"It\u0027s a condensation reaction that forms"},{"Start":"03:00.290 ","End":"03:07.580","Text":"the glycosidic bond and both molecules are now bound to the same oxygen."},{"Start":"03:07.580 ","End":"03:09.770","Text":"This is the glycosidic bond."},{"Start":"03:09.770 ","End":"03:12.700","Text":"This is how they are now together."},{"Start":"03:12.700 ","End":"03:15.805","Text":"You have the OH from 1,"},{"Start":"03:15.805 ","End":"03:17.885","Text":"the hydrogen from the other OH."},{"Start":"03:17.885 ","End":"03:20.330","Text":"These come together form H_2O,"},{"Start":"03:20.330 ","End":"03:23.030","Text":"2 Hs plus an oxygen, water."},{"Start":"03:23.030 ","End":"03:30.200","Text":"Both molecules now are joined to 1 common oxygen and this is their glycosidic link."},{"Start":"03:30.200 ","End":"03:32.195","Text":"We\u0027re going to go over this and repeat this."},{"Start":"03:32.195 ","End":"03:35.480","Text":"It will be second nature to you and you will know this as"},{"Start":"03:35.480 ","End":"03:39.185","Text":"a concept to also understand how these processes occur."},{"Start":"03:39.185 ","End":"03:43.665","Text":"The most abundant are the disaccharides with 2 monosaccharide units."},{"Start":"03:43.665 ","End":"03:46.555","Text":"Di means 2."},{"Start":"03:46.555 ","End":"03:49.940","Text":"Typical is sucrose cane sugar,"},{"Start":"03:49.940 ","End":"03:54.185","Text":"which consists of a 6-carbon sugar D-glucose that we mentioned"},{"Start":"03:54.185 ","End":"03:58.860","Text":"is referred to as dextrose and D-fructose."},{"Start":"03:58.860 ","End":"04:02.810","Text":"What you see is you have a glucose,"},{"Start":"04:02.810 ","End":"04:11.040","Text":"also known as dextrose, and fructose."},{"Start":"04:11.040 ","End":"04:15.170","Text":"This is also a D-fructose and what this means we\u0027ll go into in a later lesson."},{"Start":"04:15.170 ","End":"04:16.550","Text":"These come together."},{"Start":"04:16.550 ","End":"04:19.010","Text":"You have the OH and the OH,"},{"Start":"04:19.010 ","End":"04:22.700","Text":"they come together, H_2O is released."},{"Start":"04:22.700 ","End":"04:26.015","Text":"You have this in green."},{"Start":"04:26.015 ","End":"04:28.190","Text":"Hydrogen, oxygen that\u0027s released,"},{"Start":"04:28.190 ","End":"04:29.660","Text":"and the hydrogen is released here,"},{"Start":"04:29.660 ","End":"04:31.835","Text":"the ones in green are what are released."},{"Start":"04:31.835 ","End":"04:36.199","Text":"They form this water molecule and as condensation reaction."},{"Start":"04:36.199 ","End":"04:39.980","Text":"Now both glucose and fructose are bound together with"},{"Start":"04:39.980 ","End":"04:43.759","Text":"1 common oxygen and they have formed the sucrose molecule."},{"Start":"04:43.759 ","End":"04:48.015","Text":"In cells, most oligosaccharides consisting of 3 or more units"},{"Start":"04:48.015 ","End":"04:52.610","Text":"do not occur as free entities but are joined to non-sugar molecules,"},{"Start":"04:52.610 ","End":"04:55.745","Text":"lipids, or proteins in glycoconjugates,"},{"Start":"04:55.745 ","End":"04:58.189","Text":"which is a term we mentioned previously."},{"Start":"04:58.189 ","End":"05:04.055","Text":"The polysaccharides, sugar polymers containing more than 20 or so monosaccharide units."},{"Start":"05:04.055 ","End":"05:06.200","Text":"Versus remember the term oligosaccharides,"},{"Start":"05:06.200 ","End":"05:08.930","Text":"it has multiple saccharides but not as high of"},{"Start":"05:08.930 ","End":"05:13.430","Text":"a number and some have hundreds or thousands of units."},{"Start":"05:13.430 ","End":"05:15.755","Text":"Some polysaccharides such as cellulose,"},{"Start":"05:15.755 ","End":"05:18.215","Text":"which we hadn\u0027t mentioned are linear chains."},{"Start":"05:18.215 ","End":"05:21.890","Text":"As you see here, these are linear chains that are stacked together."},{"Start":"05:21.890 ","End":"05:28.700","Text":"Each cellulose chain is 1 linear chain and these just get stacked off."},{"Start":"05:28.700 ","End":"05:31.595","Text":"If you go back to the previous figure to remind you,"},{"Start":"05:31.595 ","End":"05:34.460","Text":"it is a linear chain of molecules."},{"Start":"05:34.460 ","End":"05:36.815","Text":"This is cellulose, while others,"},{"Start":"05:36.815 ","End":"05:39.260","Text":"such as glycogen are branched."},{"Start":"05:39.260 ","End":"05:40.700","Text":"If you see here glycogen,"},{"Start":"05:40.700 ","End":"05:43.955","Text":"you have a chain that is branched to"},{"Start":"05:43.955 ","End":"05:48.425","Text":"other chains that are all part of the glycogen molecule."},{"Start":"05:48.425 ","End":"05:53.810","Text":"Both glycogen and cellulose consists of recurring units of D-glucose,"},{"Start":"05:53.810 ","End":"05:57.650","Text":"which we also mentioned to be known as dextrose."},{"Start":"05:57.650 ","End":"06:01.880","Text":"All these individual units are the same."},{"Start":"06:01.880 ","End":"06:07.535","Text":"D-glucose is the monomer that makes up cellulose and glycogen,"},{"Start":"06:07.535 ","End":"06:10.490","Text":"but they differ in the type of"},{"Start":"06:10.490 ","End":"06:13.640","Text":"glycosidic linkage and consequently have"},{"Start":"06:13.640 ","End":"06:16.790","Text":"strikingly different properties and biological roles."},{"Start":"06:16.790 ","End":"06:19.969","Text":"You have cellulose versus glycogen."},{"Start":"06:19.969 ","End":"06:21.380","Text":"These are very different."},{"Start":"06:21.380 ","End":"06:22.730","Text":"This will be an animal product."},{"Start":"06:22.730 ","End":"06:25.310","Text":"This is like meat, whereas in plants,"},{"Start":"06:25.310 ","End":"06:29.090","Text":"cellulose is the meat of the plant is leaves."},{"Start":"06:29.090 ","End":"06:31.835","Text":"These are very different and the properties when we think"},{"Start":"06:31.835 ","End":"06:35.500","Text":"about animal tissue versus plant tissue."},{"Start":"06:35.500 ","End":"06:40.895","Text":"To summarize carbohydrates, the concepts we introduced,"},{"Start":"06:40.895 ","End":"06:43.770","Text":"we have 3 main groups."},{"Start":"06:43.770 ","End":"06:45.285","Text":"We have the monosaccharides,"},{"Start":"06:45.285 ","End":"06:47.370","Text":"the disaccharides, and the polysaccharides."},{"Start":"06:47.370 ","End":"06:50.375","Text":"The monosaccharides come from the word mono, single,"},{"Start":"06:50.375 ","End":"06:54.260","Text":"and all come from saccharide, from Greek,"},{"Start":"06:54.260 ","End":"06:58.880","Text":"from sugar, so monosaccharide, 1 sugar molecule."},{"Start":"06:58.880 ","End":"07:06.455","Text":"Disaccharide, this is 2 molecules of sugar."},{"Start":"07:06.455 ","End":"07:07.850","Text":"This is a disaccharide."},{"Start":"07:07.850 ","End":"07:10.430","Text":"You have the example of glucose,"},{"Start":"07:10.430 ","End":"07:13.850","Text":"and you have 2 glucose molecules makes maltose."},{"Start":"07:13.850 ","End":"07:16.910","Text":"Then you have a polysaccharide and that makes"},{"Start":"07:16.910 ","End":"07:21.635","Text":"many sugars into a chain and you have cellulose."},{"Start":"07:21.635 ","End":"07:28.025","Text":"We also mentioned glycogen that are both chains of glucose,"},{"Start":"07:28.025 ","End":"07:31.130","Text":"multiple monomers chained together,"},{"Start":"07:31.130 ","End":"07:34.115","Text":"generally more than 20 of these."},{"Start":"07:34.115 ","End":"07:37.175","Text":"Now, this week completed the introduction to carbohydrates"},{"Start":"07:37.175 ","End":"07:41.570","Text":"within the topic of simple carbohydrates in the chapter on carbohydrates."},{"Start":"07:41.570 ","End":"07:45.655","Text":"You should be able to know the general roles carbohydrates in living things have."},{"Start":"07:45.655 ","End":"07:47.690","Text":"The classification of carbohydrates."},{"Start":"07:47.690 ","End":"07:50.255","Text":"We mentioned 3 main classifications."},{"Start":"07:50.255 ","End":"07:52.490","Text":"List the common monosaccharides,"},{"Start":"07:52.490 ","End":"07:53.780","Text":"disaccharides, and polysaccharides."},{"Start":"07:53.780 ","End":"07:56.970","Text":"We mentioned a couple for each."}],"ID":30477},{"Watched":false,"Name":"Exercise 1","Duration":"4m 22s","ChapterTopicVideoID":28922,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.185","Text":"Welcome to our first exercise on simple carbohydrates."},{"Start":"00:04.185 ","End":"00:07.065","Text":"Part 1, which statement is true?"},{"Start":"00:07.065 ","End":"00:10.305","Text":"Carbohydrates are the most abundant biomolecules on Earth."},{"Start":"00:10.305 ","End":"00:12.780","Text":"B, photosynthesis converts"},{"Start":"00:12.780 ","End":"00:15.810","Text":"less than 1 billion metric tons of carbon dioxide"},{"Start":"00:15.810 ","End":"00:19.080","Text":"and water molecules into cellulose and other plant products."},{"Start":"00:19.080 ","End":"00:23.765","Text":"C, sugar and starch are a dietary staple in few parts of the world."},{"Start":"00:23.765 ","End":"00:26.480","Text":"D, the oxidation of carbohydrates is"},{"Start":"00:26.480 ","End":"00:30.265","Text":"the central energy yielding pathway in most photosynthetic cells,"},{"Start":"00:30.265 ","End":"00:35.165","Text":"and E, soluble carbohydrate polymers serve as structural and protective elements."},{"Start":"00:35.165 ","End":"00:38.270","Text":"Other carbohydrate polymers lubricate skeletal joints and"},{"Start":"00:38.270 ","End":"00:41.980","Text":"participate in recognition and adhesion between cells."},{"Start":"00:41.980 ","End":"00:43.905","Text":"Let\u0027s start one at a time."},{"Start":"00:43.905 ","End":"00:47.330","Text":"A, carbohydrates are the most abundant biomolecules on Earth."},{"Start":"00:47.330 ","End":"00:50.620","Text":"This sounds like a true statement that we mentioned early on."},{"Start":"00:50.620 ","End":"00:52.515","Text":"This is a possibility."},{"Start":"00:52.515 ","End":"00:55.430","Text":"Let\u0027s check B. Photosynthesis converts"},{"Start":"00:55.430 ","End":"00:58.010","Text":"less than 1 billion metric tons of carbon dioxide and"},{"Start":"00:58.010 ","End":"01:01.445","Text":"H_2O or water molecules into cellulose and other plant products."},{"Start":"01:01.445 ","End":"01:04.520","Text":"Well, photosynthesis is something that"},{"Start":"01:04.520 ","End":"01:08.390","Text":"converts carbon dioxide and water into cellulose and other plant products,"},{"Start":"01:08.390 ","End":"01:13.430","Text":"but the amount we mentioned is greater than 1 billion."},{"Start":"01:13.430 ","End":"01:16.085","Text":"Do you remember the figure that was mentioned?"},{"Start":"01:16.085 ","End":"01:19.120","Text":"It is enormous."},{"Start":"01:19.120 ","End":"01:24.905","Text":"This seems like it may not be true because of this little detail."},{"Start":"01:24.905 ","End":"01:28.940","Text":"Now sugar and starch are dietary staple in few parts of the world."},{"Start":"01:28.940 ","End":"01:32.480","Text":"Sugar and starch are a dietary staple."},{"Start":"01:32.480 ","End":"01:35.960","Text":"We eat these things, sugars and starches."},{"Start":"01:35.960 ","End":"01:41.380","Text":"Starches are a complex sugar like potatoes and sweet potatoes."},{"Start":"01:41.380 ","End":"01:43.490","Text":"These are dietary staple,"},{"Start":"01:43.490 ","End":"01:45.935","Text":"yet not in few parts of the world,"},{"Start":"01:45.935 ","End":"01:48.120","Text":"rather in many parts of the world."},{"Start":"01:48.120 ","End":"01:51.380","Text":"Again, this sounds like a little inaccurate."},{"Start":"01:51.380 ","End":"01:54.680","Text":"Let\u0027s move to D. The oxidation of carbohydrates is"},{"Start":"01:54.680 ","End":"01:58.520","Text":"the central energy yielding pathway in most photosynthetic cells."},{"Start":"01:58.520 ","End":"02:01.145","Text":"It is a central and yielding pathway,"},{"Start":"02:01.145 ","End":"02:05.210","Text":"but actually in most non-photosynthetic cells,"},{"Start":"02:05.210 ","End":"02:11.780","Text":"because in photosynthetic cells it also does photosynthesis to yield energy."},{"Start":"02:11.780 ","End":"02:17.470","Text":"Again, this here makes it inaccurate."},{"Start":"02:17.470 ","End":"02:19.805","Text":"The next one is E,"},{"Start":"02:19.805 ","End":"02:23.660","Text":"soluble carbohydrate polymers serve as structural and protective elements."},{"Start":"02:23.660 ","End":"02:27.680","Text":"Other carbohydrate polymers lubricate skeletal joints and participate in"},{"Start":"02:27.680 ","End":"02:32.675","Text":"recognition and adhesion between cells."},{"Start":"02:32.675 ","End":"02:34.850","Text":"Well, this also sounds true."},{"Start":"02:34.850 ","End":"02:38.705","Text":"But if these were soluble,"},{"Start":"02:38.705 ","End":"02:43.160","Text":"they weren\u0027t necessarily structural because they would then be in solution."},{"Start":"02:43.160 ","End":"02:46.355","Text":"Therefore, this seems like it\u0027s inaccurate."},{"Start":"02:46.355 ","End":"02:48.010","Text":"This leaves us saying,"},{"Start":"02:48.010 ","End":"02:52.940","Text":"A sounds like the true statement because B sounds wrong, C sounds inaccurate,"},{"Start":"02:52.940 ","End":"02:57.005","Text":"D sounds inaccurate, as well as E. Our accurate statement"},{"Start":"02:57.005 ","End":"03:01.340","Text":"is carbohydrates are the most abundant biomolecules on Earth."},{"Start":"03:01.340 ","End":"03:03.530","Text":"This is our true statement."},{"Start":"03:03.530 ","End":"03:07.400","Text":"Part 2, correct the false statements from Part 1."},{"Start":"03:07.400 ","End":"03:09.320","Text":"Well, A was correct,"},{"Start":"03:09.320 ","End":"03:11.165","Text":"so there\u0027s nothing to correct for it."},{"Start":"03:11.165 ","End":"03:15.740","Text":"B we mentioned it is correct except"},{"Start":"03:15.740 ","End":"03:21.680","Text":"for the amount that is mentioned to be converted,"},{"Start":"03:21.680 ","End":"03:24.650","Text":"it is not less than 1 billion metric tons,"},{"Start":"03:24.650 ","End":"03:30.980","Text":"rather it is more than a 100 billion metric tons worldwide that are"},{"Start":"03:30.980 ","End":"03:38.475","Text":"converted by photosynthesis into plant products from CO_2 and H_2O."},{"Start":"03:38.475 ","End":"03:40.725","Text":"As for C,"},{"Start":"03:40.725 ","End":"03:43.880","Text":"sugar and starch are dietary staples in few parts of the world."},{"Start":"03:43.880 ","End":"03:47.645","Text":"Well, we said in most parts of the world,"},{"Start":"03:47.645 ","End":"03:49.490","Text":"this is the food source,"},{"Start":"03:49.490 ","End":"03:54.635","Text":"the energy, dietary staple in most parts of the world."},{"Start":"03:54.635 ","End":"03:57.350","Text":"As for D, the oxidation of carbohydrates is"},{"Start":"03:57.350 ","End":"04:03.290","Text":"the central energy yielding pathway in most non-photosynthetic cells."},{"Start":"04:03.290 ","End":"04:04.895","Text":"That\u0027s what makes this correct."},{"Start":"04:04.895 ","End":"04:06.980","Text":"Then for the last one, E,"},{"Start":"04:06.980 ","End":"04:09.290","Text":"we mentioned the solubility."},{"Start":"04:09.290 ","End":"04:13.010","Text":"Insoluble carbohydrate polymers serve as structural and protective elements."},{"Start":"04:13.010 ","End":"04:16.130","Text":"Other carbohydrate polymers lubricate skeletal joints and"},{"Start":"04:16.130 ","End":"04:19.700","Text":"participate in recognition and adhesion between cells."},{"Start":"04:19.700 ","End":"04:22.830","Text":"With this, we completed our first exercise."}],"ID":30478},{"Watched":false,"Name":"Exercise 2","Duration":"56s","ChapterTopicVideoID":28923,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:03.990","Text":"Welcome to another exercise within simple carbohydrates."},{"Start":"00:03.990 ","End":"00:06.255","Text":"What are glycoconjugates?"},{"Start":"00:06.255 ","End":"00:11.685","Text":"We introduced this term and as a hint you have glyco and conjugates,"},{"Start":"00:11.685 ","End":"00:13.635","Text":"2 words that can hit."},{"Start":"00:13.635 ","End":"00:15.570","Text":"Glyco sounds like what?"},{"Start":"00:15.570 ","End":"00:18.720","Text":"Glycogen sugar."},{"Start":"00:18.720 ","End":"00:22.455","Text":"Conjugate means bound, combined together."},{"Start":"00:22.455 ","End":"00:25.890","Text":"Glycoconjugates are complex carbohydrate polymers that are"},{"Start":"00:25.890 ","End":"00:29.535","Text":"covalently attached to proteins or lipids which"},{"Start":"00:29.535 ","End":"00:37.310","Text":"are respectively called glycoprotein or glycolipids or can be bound to amino acids."},{"Start":"00:37.310 ","End":"00:42.395","Text":"In other words, a protein or lipid with covalently linked glycans,"},{"Start":"00:42.395 ","End":"00:46.840","Text":"a synonym of carbohydrates, glycans."},{"Start":"00:46.840 ","End":"00:50.780","Text":"These can act as signals that determine the intracellular location or"},{"Start":"00:50.780 ","End":"00:55.025","Text":"metabolic fate of these glycoconjugates."},{"Start":"00:55.025 ","End":"00:57.540","Text":"See you in the next exercise."}],"ID":30479},{"Watched":false,"Name":"Exercise 3","Duration":"1m 23s","ChapterTopicVideoID":28924,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.265","Text":"Let\u0027s tackle another exercise on simple carbohydrates."},{"Start":"00:04.265 ","End":"00:08.740","Text":"Monosaccarides, the simplest carbohydrates are classified into 2 main types."},{"Start":"00:08.740 ","End":"00:10.540","Text":"Name and describe these."},{"Start":"00:10.540 ","End":"00:14.530","Text":"Monosaccarides are classified into 2 main types."},{"Start":"00:14.530 ","End":"00:20.320","Text":"What are these? Carbohydrates are either aldehydes or ketones."},{"Start":"00:20.320 ","End":"00:26.200","Text":"Polyhydroxy aldehyde or ketones are molecules with more than 1 hydroxyl group,"},{"Start":"00:26.200 ","End":"00:27.970","Text":"(-OH), and a carbonyl group,"},{"Start":"00:27.970 ","End":"00:31.675","Text":"a carbon bound to oxygen, either at the terminal carbon atom,"},{"Start":"00:31.675 ","End":"00:33.340","Text":"meaning at the end of the carbon atom,"},{"Start":"00:33.340 ","End":"00:34.495","Text":"which is an aldose,"},{"Start":"00:34.495 ","End":"00:38.160","Text":"or at the second carbon atom, a ketose."},{"Start":"00:38.160 ","End":"00:43.255","Text":"Polyhydroxy aldehydes are organic compounds containing many hydroxyl groups, OH,"},{"Start":"00:43.255 ","End":"00:46.340","Text":"and an aldehyde group (-C(=O)H),"},{"Start":"00:46.930 ","End":"00:49.070","Text":"because it\u0027s at the end,"},{"Start":"00:49.070 ","End":"00:55.895","Text":"all for binding is 1 to the rest of the carbohydrate chain and then oxygen and hydrogen."},{"Start":"00:55.895 ","End":"00:58.610","Text":"While polyhydroxy ketones are organic compounds"},{"Start":"00:58.610 ","End":"01:01.535","Text":"containing many hydroxyl groups and a ketone group,"},{"Start":"01:01.535 ","End":"01:06.080","Text":"meaning carbon bound to the oxygen where it is bound to the rest of the chain,"},{"Start":"01:06.080 ","End":"01:13.430","Text":"other carbon groups from both sides because it is actually in the body of the chain,"},{"Start":"01:13.430 ","End":"01:14.900","Text":"in part of the chain,"},{"Start":"01:14.900 ","End":"01:18.304","Text":"not at the edge like the aldose."},{"Start":"01:18.304 ","End":"01:20.225","Text":"We completed with that,"},{"Start":"01:20.225 ","End":"01:24.030","Text":"the question on the types of monosaccharides."}],"ID":30480},{"Watched":false,"Name":"Exercise 4","Duration":"3m 25s","ChapterTopicVideoID":28925,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.990","Text":"Let\u0027s jump into another exercise on simple carbohydrates."},{"Start":"00:04.990 ","End":"00:08.360","Text":"There are 3 major size classes of carbohydrates,"},{"Start":"00:08.360 ","End":"00:09.740","Text":"list and describe these."},{"Start":"00:09.740 ","End":"00:16.875","Text":"The 3 major size class of carbohydrates are: monosaccharides,"},{"Start":"00:16.875 ","End":"00:24.405","Text":"simple sugars that consists of a single polyhydroxy aldehyde or ketone unit, single mono,"},{"Start":"00:24.405 ","End":"00:27.825","Text":"the most abundant Monosaccharides in nature is the 6-carbon sugar,"},{"Start":"00:27.825 ","End":"00:33.990","Text":"D-glucose which we also introduced as being called as dextrose."},{"Start":"00:33.990 ","End":"00:38.550","Text":"Monosaccharides of more than 4 carbons tend to have cyclic structures,"},{"Start":"00:38.550 ","End":"00:39.570","Text":"so we have dextrose,"},{"Start":"00:39.570 ","End":"00:41.250","Text":"that\u0027s a 6-carbon sugar."},{"Start":"00:41.250 ","End":"00:44.490","Text":"It can also form a cyclic structure"},{"Start":"00:44.490 ","End":"00:48.275","Text":"and as you see it\u0027s this carbon and this hydrogen that will bind,"},{"Start":"00:48.275 ","End":"00:57.790","Text":"the hydrogen will be released and form this ring."},{"Start":"00:57.790 ","End":"01:02.750","Text":"We have the second class of carbohydrates is oligosaccharides,"},{"Start":"01:02.750 ","End":"01:04.895","Text":"consist of short chains of Monosaccharides units,"},{"Start":"01:04.895 ","End":"01:07.400","Text":"or residues joined by glycosidic bonds,"},{"Start":"01:07.400 ","End":"01:08.810","Text":"meaning there\u0027s more than 1,"},{"Start":"01:08.810 ","End":"01:11.330","Text":"but there aren\u0027t necessarily a high number of"},{"Start":"01:11.330 ","End":"01:14.525","Text":"monomers which would then put it in the third group,"},{"Start":"01:14.525 ","End":"01:19.770","Text":"the biggest size class and the most abundant are the disaccharides, meaning double,"},{"Start":"01:19.770 ","End":"01:23.445","Text":"meaning 2 monosaccharides units and we gave examples of these;"},{"Start":"01:23.445 ","End":"01:25.185","Text":"sucrose, cane sugar,"},{"Start":"01:25.185 ","End":"01:31.480","Text":"which consists of the 6-carbon sugars D-glucose, dextrose, and D-fructose."},{"Start":"01:31.480 ","End":"01:35.660","Text":"Glucose and fructose makes up sucrose cane sugar."},{"Start":"01:35.660 ","End":"01:39.230","Text":"This is the simple sugar that we use to sweeten things."},{"Start":"01:39.230 ","End":"01:40.550","Text":"It\u0027s a disaccharide,"},{"Start":"01:40.550 ","End":"01:44.840","Text":"it\u0027s an oligosaccharide and it is formed by joining"},{"Start":"01:44.840 ","End":"01:47.750","Text":"these 2 individual monosaccharides in"},{"Start":"01:47.750 ","End":"01:50.090","Text":"a condensation reaction where water is"},{"Start":"01:50.090 ","End":"01:53.180","Text":"released because you have the OH in green and the H here in green,"},{"Start":"01:53.180 ","End":"01:55.580","Text":"these are marked as what is being released and then"},{"Start":"01:55.580 ","End":"01:59.675","Text":"this carbon attaches to this oxygen instead of to this oxygen."},{"Start":"01:59.675 ","End":"02:02.675","Text":"This oxygen is now bounded settle to the carbon,"},{"Start":"02:02.675 ","End":"02:07.590","Text":"is bound to another hydrogen,"},{"Start":"02:07.590 ","End":"02:10.460","Text":"you have water released and you have the sucrose molecule."},{"Start":"02:10.460 ","End":"02:12.590","Text":"In cells, oligosaccharides consisting of"},{"Start":"02:12.590 ","End":"02:15.275","Text":"3 or more units are joined to non sugar molecules,"},{"Start":"02:15.275 ","End":"02:18.200","Text":"lipids or proteins in glycoconjugates."},{"Start":"02:18.200 ","End":"02:21.230","Text":"We also have ones that are bind to amino acids,"},{"Start":"02:21.230 ","End":"02:25.610","Text":"but this is what\u0027s more common lipids or proteins and it\u0027s glycoconjugates."},{"Start":"02:25.610 ","End":"02:30.965","Text":"The third class of the bigger size carbohydrates are polysaccharides."},{"Start":"02:30.965 ","End":"02:33.320","Text":"These are sugar polymers containing"},{"Start":"02:33.320 ","End":"02:38.720","Text":"more than 20 or so monosaccharide units and some have hundreds or thousands of units,"},{"Start":"02:38.720 ","End":"02:40.610","Text":"these are really big."},{"Start":"02:40.610 ","End":"02:42.950","Text":"Some polysaccharides such as cellulose,"},{"Start":"02:42.950 ","End":"02:44.420","Text":"are linear chains,"},{"Start":"02:44.420 ","End":"02:48.695","Text":"you see here they form a line of a chain,"},{"Start":"02:48.695 ","End":"02:51.080","Text":"others are branched, as you\u0027ve seen,"},{"Start":"02:51.080 ","End":"02:54.265","Text":"glycogen or in starch."},{"Start":"02:54.265 ","End":"02:57.680","Text":"All 3 that we mentioned are the monosaccharides,"},{"Start":"02:57.680 ","End":"03:00.065","Text":"as you see here; glucose, fructose, and galactose."},{"Start":"03:00.065 ","End":"03:04.010","Text":"Oligosaccharides, the common ones are disaccharides,"},{"Start":"03:04.010 ","End":"03:05.795","Text":"and we mentioned sucrose."},{"Start":"03:05.795 ","End":"03:11.205","Text":"We also mentioned maltose which is made of 2 glucose monomers."},{"Start":"03:11.205 ","End":"03:13.700","Text":"You have that polysaccharides which are sugar and polymers"},{"Start":"03:13.700 ","End":"03:16.530","Text":"containing more than 20 or so monosaccharides."},{"Start":"03:16.530 ","End":"03:18.830","Text":"They\u0027re very long chains and these are the starch, glycogen,"},{"Start":"03:18.830 ","End":"03:22.460","Text":"and cellulose where we mentioned more glycogen and cellulose."},{"Start":"03:22.460 ","End":"03:25.980","Text":"With that, we completed this exercise."}],"ID":30481},{"Watched":false,"Name":"Monosaccharides","Duration":"9m 5s","ChapterTopicVideoID":28931,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.760","Text":"Welcome back to our lesson on monosaccharides and disaccharides within carbohydrates."},{"Start":"00:05.760 ","End":"00:09.165","Text":"In this section, we will learn about the different types of monosaccharides,"},{"Start":"00:09.165 ","End":"00:13.605","Text":"and the structure and difference between aldose and ketose."},{"Start":"00:13.605 ","End":"00:16.125","Text":"The simplest of the carbohydrates,"},{"Start":"00:16.125 ","End":"00:19.980","Text":"the monosaccharides are either aldehydes or ketones,"},{"Start":"00:19.980 ","End":"00:22.800","Text":"with 2 or more hydroxyl groups."},{"Start":"00:22.800 ","End":"00:24.900","Text":"The 6 carbon monosaccharides,"},{"Start":"00:24.900 ","End":"00:29.160","Text":"glucose and fructose have 5 hydroxyl groups,"},{"Start":"00:29.160 ","End":"00:31.995","Text":"and you see these here."},{"Start":"00:31.995 ","End":"00:36.105","Text":"The numbering represents how many carbons are here,"},{"Start":"00:36.105 ","End":"00:38.175","Text":"so 6 carbon,"},{"Start":"00:38.175 ","End":"00:40.470","Text":"1, 2, 3, 4, 5, 6."},{"Start":"00:40.470 ","End":"00:41.760","Text":"1, 2, 3,"},{"Start":"00:41.760 ","End":"00:43.195","Text":"4, 5, 6."},{"Start":"00:43.195 ","End":"00:48.845","Text":"Many of these carbon atoms to which hydroxyl groups are attached are chiral centers,"},{"Start":"00:48.845 ","End":"00:53.780","Text":"and this gives rise to the many sugar stereo isomers found in nature."},{"Start":"00:53.780 ","End":"00:56.270","Text":"Hopefully, you remember the term chiral."},{"Start":"00:56.270 ","End":"00:59.570","Text":"A chiral center is defined as an atom in"},{"Start":"00:59.570 ","End":"01:03.110","Text":"a molecule that is bonded to 4 different chemical species."},{"Start":"01:03.110 ","End":"01:06.920","Text":"A carbon can have 4 bonds,"},{"Start":"01:06.920 ","End":"01:09.515","Text":"thus it is a chiral center."},{"Start":"01:09.515 ","End":"01:12.320","Text":"Now, having the ability to have"},{"Start":"01:12.320 ","End":"01:16.430","Text":"4 different groups bonded to it in such a manner that it has"},{"Start":"01:16.430 ","End":"01:21.200","Text":"a variety of structures that can be formed and a"},{"Start":"01:21.200 ","End":"01:26.319","Text":"non-superimposable mirror image when it has that it can be different,"},{"Start":"01:26.319 ","End":"01:28.610","Text":"meaning that if we put this in the mirror,"},{"Start":"01:28.610 ","End":"01:30.230","Text":"it will be different,"},{"Start":"01:30.230 ","End":"01:31.280","Text":"it will look different."},{"Start":"01:31.280 ","End":"01:32.645","Text":"If we put this in the mirror,"},{"Start":"01:32.645 ","End":"01:35.450","Text":"it will not look exactly the same."},{"Start":"01:35.450 ","End":"01:38.150","Text":"Now, we\u0027ll begin by describing the families of monosaccharides with"},{"Start":"01:38.150 ","End":"01:40.715","Text":"backbones of 3-7 carbons."},{"Start":"01:40.715 ","End":"01:44.740","Text":"Again, here we have examples of 6 carbons in the backbone."},{"Start":"01:44.740 ","End":"01:49.120","Text":"This structure, and stereo isometric forms the different forms that they can take,"},{"Start":"01:49.120 ","End":"01:51.710","Text":"we mentioned before it can be linear or cyclic,"},{"Start":"01:51.710 ","End":"01:53.060","Text":"and the means of representing"},{"Start":"01:53.060 ","End":"01:56.450","Text":"the 3-dimensional structures on paper are things we\u0027re going to go over."},{"Start":"01:56.450 ","End":"02:00.535","Text":"We then discuss several chemical reactions of the carbonyl groups in monosaccharides."},{"Start":"02:00.535 ","End":"02:04.130","Text":"One such reaction, the addition of a hydroxyl group from within the same molecule"},{"Start":"02:04.130 ","End":"02:07.775","Text":"generates this cyclic form of 5 and 6 carbon sugars,"},{"Start":"02:07.775 ","End":"02:12.965","Text":"the form that predominate in aqueous solutions and creates a new chiral center,"},{"Start":"02:12.965 ","End":"02:16.880","Text":"adding further stereochemical complexity to this class of compounds."},{"Start":"02:16.880 ","End":"02:21.290","Text":"The nomenclature for unambiguously specify and configuration about each carbon atom in"},{"Start":"02:21.290 ","End":"02:23.240","Text":"acyclic form and a means of representing"},{"Start":"02:23.240 ","End":"02:26.305","Text":"these structures on paper are therefore described in some detail,"},{"Start":"02:26.305 ","End":"02:31.010","Text":"and this information will be useful as we discuss the metabolism of monosaccharides."},{"Start":"02:31.010 ","End":"02:35.840","Text":"Well, the 2 families of monosaccharides are aldoses and ketoses."},{"Start":"02:35.840 ","End":"02:41.040","Text":"Monosaccharides are colorless crystalline solids that are freely soluble in water,"},{"Start":"02:41.040 ","End":"02:43.985","Text":"but insoluble in non-polar solvents."},{"Start":"02:43.985 ","End":"02:48.545","Text":"You see here is an example of ketones in different representations."},{"Start":"02:48.545 ","End":"02:50.330","Text":"This is one representation,"},{"Start":"02:50.330 ","End":"02:52.100","Text":"this is another formula,"},{"Start":"02:52.100 ","End":"02:55.730","Text":"you see a ketone and for this representation you have"},{"Start":"02:55.730 ","End":"03:00.290","Text":"the breakdown of what the ball and figure structure is broken into carbon black,"},{"Start":"03:00.290 ","End":"03:01.685","Text":"oxygen red, hydrogen blue,"},{"Start":"03:01.685 ","End":"03:05.090","Text":"and they give an example of acetone as being a ketone,"},{"Start":"03:05.090 ","End":"03:07.740","Text":"and this is its formula,"},{"Start":"03:08.350 ","End":"03:12.240","Text":"(CH_3)_2CO, and you see here acetone."},{"Start":"03:12.240 ","End":"03:16.145","Text":"The solvent that we know used to remove nail polish,"},{"Start":"03:16.145 ","End":"03:18.770","Text":"etc, is a ketone."},{"Start":"03:18.770 ","End":"03:22.795","Text":"This is one example of the various types of ketones."},{"Start":"03:22.795 ","End":"03:26.540","Text":"Now, most have a sweet taste."},{"Start":"03:26.540 ","End":"03:29.735","Text":"The backbones of common monosaccharide molecules are"},{"Start":"03:29.735 ","End":"03:34.420","Text":"unbranched carbon chains in which all the carbon atoms are linked by single bonds."},{"Start":"03:34.420 ","End":"03:35.685","Text":"In the open chain form,"},{"Start":"03:35.685 ","End":"03:41.570","Text":"1 of the carbon atoms is double bonded to an oxygen atom to form a carbonyl group."},{"Start":"03:41.570 ","End":"03:43.760","Text":"This is the carbonyl group right here."},{"Start":"03:43.760 ","End":"03:46.450","Text":"This is the carbonyl group."},{"Start":"03:46.450 ","End":"03:50.030","Text":"Each of the other carbon atoms have a hydroxyl group."},{"Start":"03:50.030 ","End":"03:52.730","Text":"This right here, hydro,"},{"Start":"03:52.730 ","End":"03:56.210","Text":"hydrogen, oxyl, oxygen, hydroxyl group."},{"Start":"03:56.210 ","End":"04:00.020","Text":"Now, if the carbonyl group is at the end of the carbon chain,"},{"Start":"04:00.020 ","End":"04:02.725","Text":"that is in an aldehyde group and,"},{"Start":"04:02.725 ","End":"04:05.315","Text":"the monosaccharide is an aldose."},{"Start":"04:05.315 ","End":"04:07.150","Text":"Glucose is an example of it."},{"Start":"04:07.150 ","End":"04:13.485","Text":"The carbonyl group, the carbon that is double bound to the oxygen, right here,"},{"Start":"04:13.485 ","End":"04:15.960","Text":"it\u0027s bound only 1, 2,"},{"Start":"04:15.960 ","End":"04:18.910","Text":"and here you have a double bond with oxygen,"},{"Start":"04:18.910 ","End":"04:21.565","Text":"this is an aldose."},{"Start":"04:21.565 ","End":"04:29.070","Text":"Now, glucose and galactose are examples of this."},{"Start":"04:30.160 ","End":"04:32.890","Text":"What we see here is a glucose."},{"Start":"04:32.890 ","End":"04:36.910","Text":"Now, if the carbonyl group is at any other position which"},{"Start":"04:36.910 ","End":"04:40.975","Text":"means it\u0027s in a ketone group or commonly in the second position,"},{"Start":"04:40.975 ","End":"04:43.795","Text":"the monosaccharide is a ketose."},{"Start":"04:43.795 ","End":"04:47.370","Text":"You here see the double bond,"},{"Start":"04:47.370 ","End":"04:51.030","Text":"it\u0027s the fatter bond at this molecule,"},{"Start":"04:51.030 ","End":"04:52.900","Text":"which isn\u0027t the tunnel carbon."},{"Start":"04:52.900 ","End":"04:59.190","Text":"This is therefore a ketose and fructose is an example of this."},{"Start":"04:59.190 ","End":"05:00.970","Text":"If we look down here,"},{"Start":"05:00.970 ","End":"05:06.000","Text":"carbon double bond to oxygen at the terminal end,"},{"Start":"05:06.000 ","End":"05:09.080","Text":"this is an aldose,"},{"Start":"05:09.080 ","End":"05:11.930","Text":"while double bond to the oxygen,"},{"Start":"05:11.930 ","End":"05:14.680","Text":"it\u0027s a carbon a ketone group,"},{"Start":"05:14.680 ","End":"05:16.690","Text":"a group in the middle of the chain,"},{"Start":"05:16.690 ","End":"05:20.570","Text":"this is a ketose."},{"Start":"05:21.600 ","End":"05:27.235","Text":"The simplest monosaccharides are the 2, 3-carbon trioses."},{"Start":"05:27.235 ","End":"05:33.520","Text":"You have the glyceraldehyde and aldotriose."},{"Start":"05:33.520 ","End":"05:36.900","Text":"Aldo from aldose, triose,"},{"Start":"05:36.900 ","End":"05:41.610","Text":"meaning 3 carbon, 3 triose."},{"Start":"05:41.610 ","End":"05:44.940","Text":"The glyceraldehyde and aldotriose,"},{"Start":"05:44.940 ","End":"05:51.100","Text":"this is a simple monosaccharide with a 3-carbon chain,"},{"Start":"05:51.100 ","End":"05:53.880","Text":"meaning there are 3 carbons,"},{"Start":"05:53.880 ","End":"05:59.935","Text":"this is simple and you have the dihydroxyacetone,"},{"Start":"05:59.935 ","End":"06:05.090","Text":"which is a ketotriose, meaning from ketose."},{"Start":"06:05.120 ","End":"06:09.010","Text":"These are the simplest monosaccharides."},{"Start":"06:09.010 ","End":"06:10.450","Text":"They have 3 carbons,"},{"Start":"06:10.450 ","End":"06:15.035","Text":"that\u0027s the shortest that you can have as a monosaccharide,"},{"Start":"06:15.035 ","End":"06:17.130","Text":"3 carbons, a triose,"},{"Start":"06:17.130 ","End":"06:18.385","Text":"and you have the 2 types,"},{"Start":"06:18.385 ","End":"06:21.475","Text":"either the double bond at the terminal end,"},{"Start":"06:21.475 ","End":"06:23.755","Text":"which is an aldose,"},{"Start":"06:23.755 ","End":"06:28.420","Text":"or a double bond in a middle group carbon,"},{"Start":"06:28.420 ","End":"06:29.680","Text":"in this case the second,"},{"Start":"06:29.680 ","End":"06:31.570","Text":"which is a ketose,"},{"Start":"06:31.570 ","End":"06:37.040","Text":"and being the 3-carbon triose it\u0027s called a glyceraldehyde,"},{"Start":"06:37.040 ","End":"06:41.700","Text":"which is the aldotriose or the dihydroxyacetone,"},{"Start":"06:41.700 ","End":"06:44.145","Text":"which is a ketotriose."},{"Start":"06:44.145 ","End":"06:46.590","Text":"Monosaccharides with 4, 5, 6,"},{"Start":"06:46.590 ","End":"06:52.970","Text":"and 7 carbon atoms in their backbone are called tetroses for 4,"},{"Start":"06:52.970 ","End":"06:56.400","Text":"pentoses for 5,"},{"Start":"06:56.400 ","End":"06:59.670","Text":"hexoses for 6,"},{"Start":"06:59.670 ","End":"07:03.900","Text":"and heptoses for 7."},{"Start":"07:03.900 ","End":"07:06.330","Text":"These are what they\u0027re termed,"},{"Start":"07:06.330 ","End":"07:08.160","Text":"tetroses, pentoses, hexoses,"},{"Start":"07:08.160 ","End":"07:09.920","Text":"and heptoses respectively,"},{"Start":"07:09.920 ","End":"07:11.975","Text":"to the numbers here."},{"Start":"07:11.975 ","End":"07:18.155","Text":"There are also aldoses and ketoses of each of these chain lengths."},{"Start":"07:18.155 ","End":"07:23.415","Text":"You have aldotetroses and ketotetroses again,"},{"Start":"07:23.415 ","End":"07:25.560","Text":"standing for 4,"},{"Start":"07:25.560 ","End":"07:33.210","Text":"you have aldopentoses and ketopentoses standing for 5, and so on."},{"Start":"07:33.210 ","End":"07:37.590","Text":"Aldohexoses, ketohexoses, etc."},{"Start":"07:37.590 ","End":"07:38.895","Text":"Now, the hexoses,"},{"Start":"07:38.895 ","End":"07:42.420","Text":"which include aldohexose D-glucose and"},{"Start":"07:42.420 ","End":"07:47.375","Text":"the ketohexose D-fructose are the most common monosaccharides in nature."},{"Start":"07:47.375 ","End":"07:53.625","Text":"Remember, glucose is an aldose and fructose is a ketose,"},{"Start":"07:53.625 ","End":"07:58.961","Text":"so the hexoses that have 6 carbons: 1,"},{"Start":"07:58.961 ","End":"08:00.630","Text":"2, 3, 4, 5, 6,"},{"Start":"08:00.630 ","End":"08:02.925","Text":"1, 2, 3, 4, 5, 6."},{"Start":"08:02.925 ","End":"08:04.470","Text":"Here we have it at the terminal,"},{"Start":"08:04.470 ","End":"08:06.845","Text":"so this is from an aldose,"},{"Start":"08:06.845 ","End":"08:10.445","Text":"and here it\u0027s on a second carbon, it\u0027s a ketose."},{"Start":"08:10.445 ","End":"08:14.475","Text":"You have the hexoses, the aldohexose D-glucose,"},{"Start":"08:14.475 ","End":"08:16.395","Text":"and the ketohexose,"},{"Start":"08:16.395 ","End":"08:22.145","Text":"the D-fructose are the most common monosaccharides in nature."},{"Start":"08:22.145 ","End":"08:26.320","Text":"It\u0027s these ones that you find most commonly in nature."},{"Start":"08:26.320 ","End":"08:30.594","Text":"Now, the aldopentoses, pentose,"},{"Start":"08:30.594 ","End":"08:33.093","Text":"we have is 5 carbons, 1,"},{"Start":"08:33.093 ","End":"08:34.545","Text":"2, 3, 4, 5;"},{"Start":"08:34.545 ","End":"08:36.795","Text":"1, 2, 3, 4, 5."},{"Start":"08:36.795 ","End":"08:43.925","Text":"D-ribose and 2-deoxy-D-ribose are components of nucleotides and nucleic acids."},{"Start":"08:43.925 ","End":"08:45.710","Text":"We mentioned the ribose."},{"Start":"08:45.710 ","End":"08:49.745","Text":"This is part of the RNA molecule,"},{"Start":"08:49.745 ","End":"08:55.525","Text":"and the deoxy is part of the DNA molecule."},{"Start":"08:55.525 ","End":"08:58.430","Text":"With this, we completed the section of monosaccharides and"},{"Start":"08:58.430 ","End":"09:01.700","Text":"disaccharides and covered different types of monosaccharides and the structure,"},{"Start":"09:01.700 ","End":"09:04.980","Text":"and difference between aldose and ketose."}],"ID":30482},{"Watched":false,"Name":"Exercise 5","Duration":"2m 17s","ChapterTopicVideoID":28928,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.950","Text":"Welcome to an exercise on the lesson monosaccharides"},{"Start":"00:04.950 ","End":"00:09.690","Text":"and disaccharides within our polysaccharide chapter. Let\u0027s dive in."},{"Start":"00:09.690 ","End":"00:11.355","Text":"Which statement is true."},{"Start":"00:11.355 ","End":"00:14.550","Text":"A, the simplest of the carbohydrates are monosaccharides."},{"Start":"00:14.550 ","End":"00:18.935","Text":"B, monosaccharides are either aldehydes or ketones with 2 or more hydroxyl groups."},{"Start":"00:18.935 ","End":"00:20.690","Text":"C, the 6-carbon monosaccharides,"},{"Start":"00:20.690 ","End":"00:23.285","Text":"glucose and fructose have 5 hydroxyl groups."},{"Start":"00:23.285 ","End":"00:27.715","Text":"D, many of the carbon atoms to which hydroxyl groups are attached are chiral centers."},{"Start":"00:27.715 ","End":"00:29.375","Text":"E, all of the above."},{"Start":"00:29.375 ","End":"00:31.160","Text":"Now, let\u0027s go 1 by 1."},{"Start":"00:31.160 ","End":"00:35.135","Text":"A, the simplest carbohydrates are monosaccharides. Well, this is true."},{"Start":"00:35.135 ","End":"00:37.952","Text":"We even further mentioned of these,"},{"Start":"00:37.952 ","End":"00:41.780","Text":"which ones are the most simple and those are the trioses the ones that"},{"Start":"00:41.780 ","End":"00:46.840","Text":"have 3 carbons in their backbones, so trioses."},{"Start":"00:46.840 ","End":"00:50.585","Text":"B, monosaccharides are either aldehydes or ketones."},{"Start":"00:50.585 ","End":"00:55.865","Text":"We also said aldoses or ketose, same concept,"},{"Start":"00:55.865 ","End":"00:59.220","Text":"same term, with 2 or more hydroxyl groups,"},{"Start":"00:59.220 ","End":"01:04.270","Text":"so this is true as well because it\u0027s split to either or."},{"Start":"01:04.270 ","End":"01:11.450","Text":"C, the 6-carbon monosaccharide glucose and fructose have 5 hydroxyl groups."},{"Start":"01:11.450 ","End":"01:18.965","Text":"Well that\u0027s true as well because 1 will actually have either the aldose group or"},{"Start":"01:18.965 ","End":"01:20.990","Text":"will have the bond to"},{"Start":"01:20.990 ","End":"01:27.500","Text":"the double oxygen to define it either as an aldose or ketose so this is true as well."},{"Start":"01:27.500 ","End":"01:31.899","Text":"D, many of the carbon atoms to which hydroxyl groups are attached are chiral centers."},{"Start":"01:31.899 ","End":"01:36.365","Text":"We said this as well a chiral center as something that can have 4 bonds,"},{"Start":"01:36.365 ","End":"01:38.045","Text":"they are different therefore,"},{"Start":"01:38.045 ","End":"01:41.450","Text":"a mirror image of this would not be the same."},{"Start":"01:41.450 ","End":"01:43.265","Text":"If we have here a carbon,"},{"Start":"01:43.265 ","End":"01:45.230","Text":"so it can be another carbon,"},{"Start":"01:45.230 ","End":"01:48.528","Text":"the double bond to oxygen, hydrogen, etc."},{"Start":"01:48.528 ","End":"01:50.471","Text":"so this is true as well."},{"Start":"01:50.471 ","End":"01:53.585","Text":"Therefore, it seems as the E is what we would say,"},{"Start":"01:53.585 ","End":"01:54.920","Text":"because they all seem true."},{"Start":"01:54.920 ","End":"01:56.660","Text":"A this is true."},{"Start":"01:56.660 ","End":"01:58.970","Text":"The synthesis of the carbohydrates are monosaccharides."},{"Start":"01:58.970 ","End":"02:03.260","Text":"B, monosaccharides are either aldehydes or ketones with 2 or more hydroxyl groups."},{"Start":"02:03.260 ","End":"02:08.870","Text":"C, the 6 carbon monosaccharides glucose and fructose have 5 hydroxyl groups and D,"},{"Start":"02:08.870 ","End":"02:13.130","Text":"many of the carbon atoms to which hydroxyl groups are attached are chiral centers,"},{"Start":"02:13.130 ","End":"02:14.705","Text":"being that these are all true,"},{"Start":"02:14.705 ","End":"02:18.120","Text":"E is our correct answer."}],"ID":30483},{"Watched":false,"Name":"Exercise 6","Duration":"1m 57s","ChapterTopicVideoID":28929,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.655","Text":"Welcome to another exercise on this section of monosaccharides and disaccharides."},{"Start":"00:05.655 ","End":"00:08.340","Text":"Part 1. Complete these statements."},{"Start":"00:08.340 ","End":"00:11.325","Text":"If the carbonyl group is an end of the carbon chain,"},{"Start":"00:11.325 ","End":"00:14.010","Text":"the monosaccharide is what?"},{"Start":"00:14.010 ","End":"00:17.100","Text":"2, if the carbonyl group is at any other position,"},{"Start":"00:17.100 ","End":"00:18.645","Text":"the monosaccharide is what?"},{"Start":"00:18.645 ","End":"00:24.255","Text":"Carbonyl group, we have the carbon with the double bond to the oxygen."},{"Start":"00:24.255 ","End":"00:27.360","Text":"We defined 2 types of monosaccharides,"},{"Start":"00:27.360 ","End":"00:31.410","Text":"an aldose and a ketose."},{"Start":"00:31.410 ","End":"00:37.510","Text":"The aldose and the ketose the difference between them are where the carbonyl group is."},{"Start":"00:37.510 ","End":"00:43.175","Text":"We mentioned that when it\u0027s at the end of the carbon chain,"},{"Start":"00:43.175 ","End":"00:50.305","Text":"the terminal carbon, the monosaccharide is in aldose."},{"Start":"00:50.305 ","End":"00:54.155","Text":"Whereas, if the carbonyl group"},{"Start":"00:54.155 ","End":"00:59.165","Text":"is at any other position and coming the second carbon in the chain,"},{"Start":"00:59.165 ","End":"01:03.960","Text":"the monosaccharide is a ketose."},{"Start":"01:04.880 ","End":"01:08.585","Text":"If the carbonyl group is at the end of the carbon chain,"},{"Start":"01:08.585 ","End":"01:10.370","Text":"that isn\u0027t an aldehyde group."},{"Start":"01:10.370 ","End":"01:12.710","Text":"The monosaccharide is an aldose,"},{"Start":"01:12.710 ","End":"01:17.645","Text":"and if the carbonyl group is at any other position in a ketone group,"},{"Start":"01:17.645 ","End":"01:21.135","Text":"the monosaccharide is a ketose."},{"Start":"01:21.135 ","End":"01:28.595","Text":"Part 2. Give an example of each type of the monosaccharides mentioned in Part 1."},{"Start":"01:28.595 ","End":"01:30.560","Text":"Well, we gave an example,"},{"Start":"01:30.560 ","End":"01:34.010","Text":"showed a figure of glucose being an aldose and"},{"Start":"01:34.010 ","End":"01:37.955","Text":"we also mentioned galactose as being as a 1,"},{"Start":"01:37.955 ","End":"01:40.640","Text":"so these are examples of aldose."},{"Start":"01:40.640 ","End":"01:45.020","Text":"As for ketose, we gave the example of fructose."},{"Start":"01:45.020 ","End":"01:47.030","Text":"If you see here the carbon,"},{"Start":"01:47.030 ","End":"01:49.640","Text":"the double bond is in the second,"},{"Start":"01:49.640 ","End":"01:51.950","Text":"in the actual backbone of the chain,"},{"Start":"01:51.950 ","End":"01:55.430","Text":"not at the end as it is here."},{"Start":"01:55.430 ","End":"01:58.260","Text":"We have another exercise behind us."}],"ID":30484},{"Watched":false,"Name":"Exercise 7","Duration":"1m 24s","ChapterTopicVideoID":28930,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.040","Text":"We\u0027re tackling another exercise on monosaccharides and disaccharides."},{"Start":"00:04.040 ","End":"00:08.670","Text":"Part 1, what are the simplest monosaccharides in nature?"},{"Start":"00:08.670 ","End":"00:13.485","Text":"The simplest monosaccharides are the 2, 3-carbon trioses."},{"Start":"00:13.485 ","End":"00:16.215","Text":"These are the glyceraldehyde,"},{"Start":"00:16.215 ","End":"00:23.460","Text":"an aldotriose, and the dihydroxyacetone, a ketotriose."},{"Start":"00:23.460 ","End":"00:31.095","Text":"The simplest monosaccharides are ones that have 3 carbons in their backbone."},{"Start":"00:31.095 ","End":"00:36.825","Text":"Part 2, what are the most common monosaccharides in nature?"},{"Start":"00:36.825 ","End":"00:41.745","Text":"Well, we mentioned that the hexoses,"},{"Start":"00:41.745 ","End":"00:43.500","Text":"which include the aldohexose,"},{"Start":"00:43.500 ","End":"00:45.420","Text":"D-glucose and a ketohexose,"},{"Start":"00:45.420 ","End":"00:51.170","Text":"D-fructose are the most common monosaccharides in nature."},{"Start":"00:51.170 ","End":"00:53.660","Text":"The most common monosaccharide,"},{"Start":"00:53.660 ","End":"00:58.200","Text":"hexoses, aldohexose, and ketohexose."},{"Start":"00:58.200 ","End":"00:59.850","Text":"You have glucose as an example,"},{"Start":"00:59.850 ","End":"01:03.480","Text":"this is an aldohexose and the ketohexose,"},{"Start":"01:03.480 ","End":"01:10.940","Text":"D-fructose, these 2 specifically fructose that was given as an example for a ketose."},{"Start":"01:10.940 ","End":"01:13.745","Text":"These 2 are the most common."},{"Start":"01:13.745 ","End":"01:23.460","Text":"For short, it\u0027s glucose and fructose being the most common monosaccharides in nature."}],"ID":30485},{"Watched":false,"Name":"Monosaccharides Have asymetric Centers","Duration":"10m 55s","ChapterTopicVideoID":28932,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.820","Text":"Welcome to another lesson within the chapter of carbohydrates."},{"Start":"00:05.820 ","End":"00:07.830","Text":"This lesson is on monosaccharides,"},{"Start":"00:07.830 ","End":"00:09.450","Text":"have asymmetric centers,"},{"Start":"00:09.450 ","End":"00:11.415","Text":"and in this section we will learn"},{"Start":"00:11.415 ","End":"00:14.640","Text":"the carbohydrate enantiomers and stereoisomers terms that we"},{"Start":"00:14.640 ","End":"00:20.735","Text":"introduced early on in the Fischer projection formula and the term epimers."},{"Start":"00:20.735 ","End":"00:23.775","Text":"All the monosaccharides except dihydrate,"},{"Start":"00:23.775 ","End":"00:31.005","Text":"oxyacid tone contain 1 or more asymmetric chiral carbon atoms"},{"Start":"00:31.005 ","End":"00:35.370","Text":"and thus occur in optically active isometric forms."},{"Start":"00:35.370 ","End":"00:39.825","Text":"Remember, chiral mirror image is not the same."},{"Start":"00:39.825 ","End":"00:42.230","Text":"Being at a mirror, image is not the same."},{"Start":"00:42.230 ","End":"00:48.500","Text":"It means it\u0027s optically active because if you shine light on it,"},{"Start":"00:48.500 ","End":"00:51.080","Text":"it is different from the direction,"},{"Start":"00:51.080 ","End":"00:56.345","Text":"so results in optically active isometric forms."},{"Start":"00:56.345 ","End":"01:02.060","Text":"Now, the simplest aldose glyceraldehyde contains 1 chiral center,"},{"Start":"01:02.060 ","End":"01:03.875","Text":"the middle carbon atom,"},{"Start":"01:03.875 ","End":"01:10.590","Text":"and therefore has 2 different optical isomers or enantiomers."},{"Start":"01:10.590 ","End":"01:12.590","Text":"The term, isomer and enantiomers,"},{"Start":"01:12.590 ","End":"01:13.730","Text":"if you do not remember,"},{"Start":"01:13.730 ","End":"01:19.205","Text":"look at our previous lesson and it will re-define these for you."},{"Start":"01:19.205 ","End":"01:21.110","Text":"But the idea is that they are"},{"Start":"01:21.110 ","End":"01:27.410","Text":"same basic molecules and formulas that have a little bit of different configuration."},{"Start":"01:27.410 ","End":"01:33.050","Text":"You have these 2 different optical isomers."},{"Start":"01:33.050 ","End":"01:38.390","Text":"Now, this is the same representation"},{"Start":"01:38.390 ","End":"01:42.350","Text":"of the glyceraldehyde where you have the carbon in the middle,"},{"Start":"01:42.350 ","End":"01:44.585","Text":"but this is a ball and stick model,"},{"Start":"01:44.585 ","End":"01:49.850","Text":"whereas this is a Fischer projection formula where you have lines"},{"Start":"01:49.850 ","End":"01:55.745","Text":"and the stereo isomers are considered the 2 different mirror images of each other."},{"Start":"01:55.745 ","End":"02:00.409","Text":"Now, the ball-and-stick model shows the actual configuration of molecules by convention."},{"Start":"02:00.409 ","End":"02:02.704","Text":"In Fischer projection formulas,"},{"Start":"02:02.704 ","End":"02:05.420","Text":"horizontal bonds, these,"},{"Start":"02:05.420 ","End":"02:08.220","Text":"project out of the plane of the paper toward the reader,"},{"Start":"02:08.220 ","End":"02:11.015","Text":"while the vertical bonds, these,"},{"Start":"02:11.015 ","End":"02:16.550","Text":"are considered to project behind the plane of the paper away from the reader."},{"Start":"02:16.550 ","End":"02:19.700","Text":"Moving forward with this, 1 enantiomer is designated"},{"Start":"02:19.700 ","End":"02:23.892","Text":"the D-isomer and the other is the L-isomer."},{"Start":"02:23.892 ","End":"02:33.340","Text":"Remember we mentioned dextrose as a 6 carbon D-glucose molecule."},{"Start":"02:33.340 ","End":"02:39.710","Text":"The D is what designates the orientation to the carbon."},{"Start":"02:39.710 ","End":"02:41.570","Text":"You see, these are the same,"},{"Start":"02:41.570 ","End":"02:47.225","Text":"but take a mirror image when the actual molecule is as such as"},{"Start":"02:47.225 ","End":"02:53.210","Text":"a D glyceraldehyde versus if the hydroxyl group is to the left of the carbon,"},{"Start":"02:53.210 ","End":"02:57.740","Text":"whereas the hydrogen group is to the right when the CHO top, CHO."},{"Start":"02:57.740 ","End":"03:00.335","Text":"This is the L form."},{"Start":"03:00.335 ","End":"03:03.350","Text":"Now as for other biomolecules with chiral centers,"},{"Start":"03:03.350 ","End":"03:08.315","Text":"the absolute configurations of sugars are known from X-ray crystallography."},{"Start":"03:08.315 ","End":"03:11.450","Text":"Now, the Fischer projection formulas are"},{"Start":"03:11.450 ","End":"03:14.780","Text":"often used to represent 3 dimensional sugar structures on paper,"},{"Start":"03:14.780 ","End":"03:16.655","Text":"which as can be seen in the figure."},{"Start":"03:16.655 ","End":"03:18.766","Text":"Again, give some orientation,"},{"Start":"03:18.766 ","End":"03:21.620","Text":"reminding horizontal bonds project what?"},{"Start":"03:21.620 ","End":"03:23.600","Text":"They protect towards the reader,"},{"Start":"03:23.600 ","End":"03:24.995","Text":"like they come forward,"},{"Start":"03:24.995 ","End":"03:30.680","Text":"raising the ball-and-stick models the 3D form that it comes toward us. It\u0027s towards us."},{"Start":"03:30.680 ","End":"03:34.085","Text":"Is represented in these models by the horizontal were 3C goes back,"},{"Start":"03:34.085 ","End":"03:35.970","Text":"the blue is going back."},{"Start":"03:35.970 ","End":"03:38.180","Text":"Here, it\u0027s the vertical that goes back."},{"Start":"03:38.180 ","End":"03:43.870","Text":"In general, a molecule with n chiral centers can have 2 to the power of n stereoisomers."},{"Start":"03:43.870 ","End":"03:48.390","Text":"A glyceraldehyde has 2 to the power 1 because of the 1 carbon."},{"Start":"03:48.390 ","End":"03:51.290","Text":"2, 2 stereo isomers,"},{"Start":"03:51.290 ","End":"03:54.200","Text":"the D and the L of this."},{"Start":"03:54.200 ","End":"03:57.720","Text":"The aldohexoses with 4 chiral centers,"},{"Start":"03:57.720 ","End":"04:03.825","Text":"have 2 to the power of 4, meaning 16 stereoisomers."},{"Start":"04:03.825 ","End":"04:09.140","Text":"The stereoisomers of monosaccharides of each carbon chain length can be divided"},{"Start":"04:09.140 ","End":"04:11.270","Text":"into 2 groups that different the configuration about"},{"Start":"04:11.270 ","End":"04:14.405","Text":"the chiral center most distant from the carbonyl carbon."},{"Start":"04:14.405 ","End":"04:18.875","Text":"Those in which the configuration at this reference carbon is the same as that"},{"Start":"04:18.875 ","End":"04:24.125","Text":"of D glyceraldehyde are designated D isomers,"},{"Start":"04:24.125 ","End":"04:30.050","Text":"and those with the same configuration as L glyceraldehyde are L isomers,"},{"Start":"04:30.050 ","End":"04:33.530","Text":"again D and O."},{"Start":"04:33.530 ","End":"04:36.830","Text":"In other words, when the hydroxyl group on the reference carbon is on"},{"Start":"04:36.830 ","End":"04:43.843","Text":"the right, dextro and the projection formula that has the carbonyl atom at the top,"},{"Start":"04:43.843 ","End":"04:48.193","Text":"the sugar is the D-isomer,"},{"Start":"04:48.193 ","End":"04:51.020","Text":"when on the left level,"},{"Start":"04:51.020 ","End":"04:53.510","Text":"it is the L-isomer."},{"Start":"04:53.510 ","End":"04:58.285","Text":"D-dextro L-levo,"},{"Start":"04:58.285 ","End":"05:00.740","Text":"again on hydroxyl group on the reference carbon is"},{"Start":"05:00.740 ","End":"05:03.230","Text":"on the right dextro in a projection formula."},{"Start":"05:03.230 ","End":"05:05.510","Text":"It has the carbonyl atom out the top,"},{"Start":"05:05.510 ","End":"05:07.815","Text":"the sugar, is the D-isomer."},{"Start":"05:07.815 ","End":"05:09.950","Text":"If looking at the top,"},{"Start":"05:09.950 ","End":"05:13.400","Text":"hydroxyl is on the right."},{"Start":"05:13.400 ","End":"05:18.889","Text":"It\u0027s dextro when the hydroxyl group is on the left level."},{"Start":"05:18.889 ","End":"05:24.545","Text":"Now, what you see here is another way to portray this formula."},{"Start":"05:24.545 ","End":"05:26.630","Text":"This is the perspective formula."},{"Start":"05:26.630 ","End":"05:29.225","Text":"In the perspective formula, we\u0027ve seen this."},{"Start":"05:29.225 ","End":"05:30.956","Text":"The solid wedge shape,"},{"Start":"05:30.956 ","End":"05:33.590","Text":"this points toward the reader,"},{"Start":"05:33.590 ","End":"05:42.050","Text":"while the dashed wedges point away as if this is behind the plane and this is towards us."},{"Start":"05:42.050 ","End":"05:45.999","Text":"This gets fatter because when things are closer, they\u0027re bigger,"},{"Start":"05:45.999 ","End":"05:49.550","Text":"this as it moves it gets narrower because it\u0027s"},{"Start":"05:49.550 ","End":"05:54.540","Text":"becoming further and further away, and thus smaller."},{"Start":"05:54.590 ","End":"05:58.410","Text":"Of the 16 possible aldohexoses,"},{"Start":"05:58.410 ","End":"06:03.425","Text":"8 are D forms and 8 are L forms."},{"Start":"06:03.425 ","End":"06:05.630","Text":"You see here the different types."},{"Start":"06:05.630 ","End":"06:07.595","Text":"You have 3 carbons, 4 carbons, 5 carbons,"},{"Start":"06:07.595 ","End":"06:11.300","Text":"and 6 carbon sugar molecules."},{"Start":"06:11.300 ","End":"06:17.930","Text":"In this it is the D form of these and these are the aldoses."},{"Start":"06:17.930 ","End":"06:24.470","Text":"Most of the hexoses of living organisms are D-isomers. Why D-isomers, you asked?"},{"Start":"06:24.470 ","End":"06:27.020","Text":"This is not yet known, but if you recall,"},{"Start":"06:27.020 ","End":"06:33.020","Text":"all amino acids found in proteins are exclusively 1 or 2 possible stereoisomers."},{"Start":"06:33.020 ","End":"06:37.430","Text":"Or, what led for the preference of 1 isomer over the other during evolution is unknown,"},{"Start":"06:37.430 ","End":"06:40.730","Text":"but it is possible that once 1 was more prevalent than enzymes would"},{"Start":"06:40.730 ","End":"06:44.480","Text":"retain their preference for that stereoisomer solidifying this preference,"},{"Start":"06:44.480 ","End":"06:46.055","Text":"making a bias for it."},{"Start":"06:46.055 ","End":"06:47.435","Text":"Now in this figure,"},{"Start":"06:47.435 ","End":"06:50.780","Text":"you see the structures of the D stereoisomers of which"},{"Start":"06:50.780 ","End":"06:56.135","Text":"all the aldoses and ketoses have 3-6 carbon atoms,"},{"Start":"06:56.135 ","End":"06:58.685","Text":"3 all the way to 6."},{"Start":"06:58.685 ","End":"07:04.280","Text":"Now, the carbons of a sugar are numbered beginning at the end of the chain,"},{"Start":"07:04.280 ","End":"07:07.160","Text":"nearest the carbonyl group here."},{"Start":"07:07.160 ","End":"07:09.128","Text":"You\u0027re going to have 1, 2,"},{"Start":"07:09.128 ","End":"07:10.944","Text":"3, 1, 2, 3,"},{"Start":"07:10.944 ","End":"07:12.566","Text":"4, 1, 2,"},{"Start":"07:12.566 ","End":"07:15.000","Text":"3, 4, 5, 6, etc."},{"Start":"07:15.000 ","End":"07:19.640","Text":"Each of the 8 D-aldohexoses has its own name."},{"Start":"07:19.640 ","End":"07:20.990","Text":"You have D-glucose,"},{"Start":"07:20.990 ","End":"07:22.625","Text":"you have D-galactose,"},{"Start":"07:22.625 ","End":"07:25.310","Text":"you have D-mannose, and so forth."},{"Start":"07:25.310 ","End":"07:26.585","Text":"As you see here,"},{"Start":"07:26.585 ","End":"07:27.980","Text":"they all have the names,"},{"Start":"07:27.980 ","End":"07:29.540","Text":"D-ribose, D-galactose,"},{"Start":"07:29.540 ","End":"07:31.295","Text":"D- mannose, D- glucose."},{"Start":"07:31.295 ","End":"07:34.780","Text":"The 4 and 5-carbon ketoses,"},{"Start":"07:34.780 ","End":"07:37.560","Text":"as seen here and again,"},{"Start":"07:37.560 ","End":"07:40.260","Text":"there\u0027s 3-6, as mentioned before,"},{"Start":"07:40.260 ","End":"07:44.585","Text":"3,4,5,6 carbon backbones all structured."},{"Start":"07:44.585 ","End":"07:51.200","Text":"The 4 and 5 ketoses are designated by inserting UL of a corresponding aldose,"},{"Start":"07:51.200 ","End":"07:53.530","Text":"and that\u0027s what differentiates them by name."},{"Start":"07:53.530 ","End":"07:56.705","Text":"That\u0027s how you can know if it is a ketose or an aldose."},{"Start":"07:56.705 ","End":"08:00.380","Text":"For example, you have D-ribulose is"},{"Start":"08:00.380 ","End":"08:06.200","Text":"the ketopentose corresponding to the aldopentose D-ribose."},{"Start":"08:06.200 ","End":"08:10.380","Text":"You have D-ribose."},{"Start":"08:10.760 ","End":"08:14.002","Text":"This is the aldose."},{"Start":"08:14.002 ","End":"08:22.305","Text":"The D-ketose that corresponds to this is D-ribulose."},{"Start":"08:22.305 ","End":"08:28.640","Text":"You add the UL into the ribose, split it up,"},{"Start":"08:28.640 ","End":"08:32.970","Text":"rib plus ul,"},{"Start":"08:32.970 ","End":"08:38.260","Text":"ose you have ribulose."},{"Start":"08:39.770 ","End":"08:43.595","Text":"The ketohexoses are named otherwise."},{"Start":"08:43.595 ","End":"08:48.200","Text":"For example, fructose from the Latin fructus fruit."},{"Start":"08:48.200 ","End":"08:51.485","Text":"Fruits are a rich source of this sugar."},{"Start":"08:51.485 ","End":"08:55.820","Text":"Fructose, and Sorbose from sorbus,"},{"Start":"08:55.820 ","End":"08:59.450","Text":"the genus of mountain ash from which it was found in which"},{"Start":"08:59.450 ","End":"09:03.350","Text":"has berries rich and the related sugar alcohol, sorbitol."},{"Start":"09:03.350 ","End":"09:07.310","Text":"These are not named similarly to the 4 and 5 carbon ketosis."},{"Start":"09:07.310 ","End":"09:14.490","Text":"The ketosehexose, the ketose that have 6 carbons are not named with this."},{"Start":"09:14.490 ","End":"09:20.690","Text":"2 sugars that differ in the configuration around 1 carbon atom are called epimers."},{"Start":"09:20.690 ","End":"09:22.820","Text":"For example, D-glucose and mannose,"},{"Start":"09:22.820 ","End":"09:28.565","Text":"which differ only in the stereochemistry at C2, the second carbon,"},{"Start":"09:28.565 ","End":"09:35.200","Text":"are epimers, as our D-glucose and D-galactose which differ at the C4."},{"Start":"09:35.200 ","End":"09:40.820","Text":"You have D-glucose and you have D-mannose."},{"Start":"09:40.820 ","End":"09:45.890","Text":"It differs on the C2 here; it\u0027s flipped."},{"Start":"09:45.890 ","End":"09:51.500","Text":"That\u0027s the difference verses and these are epimers at C2."},{"Start":"09:51.500 ","End":"09:56.135","Text":"This is an epimer of D-glucose at C2 versus galactose,"},{"Start":"09:56.135 ","End":"09:58.450","Text":"which is an epimer at C4."},{"Start":"09:58.450 ","End":"10:01.200","Text":"You see, here they are flipped."},{"Start":"10:01.200 ","End":"10:03.995","Text":"The hydrogens are on the right and the hydroxyl on the left."},{"Start":"10:03.995 ","End":"10:07.595","Text":"Some sugars occur naturally in their L form."},{"Start":"10:07.595 ","End":"10:10.355","Text":"Now, though we said D are more common,"},{"Start":"10:10.355 ","End":"10:12.290","Text":"you do find some in the L form,"},{"Start":"10:12.290 ","End":"10:15.415","Text":"and an example is the L-arabinose."},{"Start":"10:15.415 ","End":"10:17.840","Text":"You also find examples of L isomers of"},{"Start":"10:17.840 ","End":"10:22.010","Text":"some sugar derivatives that are common components of the glycoconjugates,"},{"Start":"10:22.010 ","End":"10:25.550","Text":"which are the classification family of carbohydrates referred to as glycans,"},{"Start":"10:25.550 ","End":"10:29.000","Text":"which are covalently linked with other chemical species such as proteins,"},{"Start":"10:29.000 ","End":"10:30.875","Text":"peptides, lipids, and other compounds."},{"Start":"10:30.875 ","End":"10:34.235","Text":"Glycoconjugates are formed in process termed glycosylation."},{"Start":"10:34.235 ","End":"10:37.160","Text":"Again, we introduced this concept very briefly,"},{"Start":"10:37.160 ","End":"10:43.118","Text":"but there are L isomers that are part of glycoconjugates."},{"Start":"10:43.118 ","End":"10:44.990","Text":"This completed the lesson."},{"Start":"10:44.990 ","End":"10:48.140","Text":"Monosaccharides have asymmetric centers and at this point"},{"Start":"10:48.140 ","End":"10:51.425","Text":"you should know carbohydrate enantiomers are stereoisomers,"},{"Start":"10:51.425 ","End":"10:55.560","Text":"the Fischer projection formula and the term Epimers."}],"ID":30486},{"Watched":false,"Name":"Exercise 8","Duration":"42s","ChapterTopicVideoID":28933,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.080 ","End":"00:03.315","Text":"Let\u0027s test our knowledge on the lesson,"},{"Start":"00:03.315 ","End":"00:05.415","Text":"monosaccharides have asymmetric centers."},{"Start":"00:05.415 ","End":"00:07.170","Text":"What is a Fischer projection formula?"},{"Start":"00:07.170 ","End":"00:09.480","Text":"Fischer projection formulas are often used to represent"},{"Start":"00:09.480 ","End":"00:11.970","Text":"3-dimensional sugar structures on paper,"},{"Start":"00:11.970 ","End":"00:14.400","Text":"which as can be seen in the figure."},{"Start":"00:14.400 ","End":"00:17.265","Text":"You have horizontal bonds and vertical bonds."},{"Start":"00:17.265 ","End":"00:20.370","Text":"The horizontal bonds, these represent bonds at"},{"Start":"00:20.370 ","End":"00:23.580","Text":"project out of the plane of the paper towards the reader, towards you,"},{"Start":"00:23.580 ","End":"00:29.760","Text":"while the vertical bonds going up to down check behind the paper on the plane,"},{"Start":"00:29.760 ","End":"00:32.055","Text":"meaning away from the reader."},{"Start":"00:32.055 ","End":"00:36.120","Text":"Horizontal bonds project out of the plane towards the reader,"},{"Start":"00:36.120 ","End":"00:41.470","Text":"towards you and vertical bonds project behind the plane away."}],"ID":30487},{"Watched":false,"Name":"Exercise 9","Duration":"1m 10s","ChapterTopicVideoID":28934,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.230","Text":"Welcome to another exercise on the lesson Monosaccharides Have Asymmetric Centers."},{"Start":"00:04.230 ","End":"00:06.750","Text":"What are the 2 groups that stereoisomers of"},{"Start":"00:06.750 ","End":"00:09.615","Text":"monosaccharides can be divided into, and how do they differ?"},{"Start":"00:09.615 ","End":"00:13.350","Text":"The stereoisomers of monosaccharides can be divided into 2 groups that differ in"},{"Start":"00:13.350 ","End":"00:18.420","Text":"the configuration about the chiral center most distant from the carbonyl carbon."},{"Start":"00:18.420 ","End":"00:24.750","Text":"The 2 groups are D isomers which are those in which the configuration"},{"Start":"00:24.750 ","End":"00:31.359","Text":"at this reference carbon is the same as that of the D-glyceraldehyde;"},{"Start":"00:31.359 ","End":"00:34.590","Text":"dextro, that\u0027s where the D comes from."},{"Start":"00:34.590 ","End":"00:39.785","Text":"In other words, when the hydroxyl group on the reference carbon is on the right,"},{"Start":"00:39.785 ","End":"00:45.830","Text":"dextro in a project and formula that has the carbonyl atom at the top is"},{"Start":"00:45.830 ","End":"00:49.880","Text":"the D-glyceraldehyde and L isomers,which are"},{"Start":"00:49.880 ","End":"00:54.213","Text":"those with the same configuration as the L-glyceraldehyde; the levo."},{"Start":"00:54.213 ","End":"01:02.023","Text":"In this case when the hydroxyl group on the reference carbon is on the left it is levo,"},{"Start":"01:02.023 ","End":"01:06.570","Text":"and therefore L. If you remember levo for left,"},{"Start":"01:06.570 ","End":"01:10.089","Text":"dextro on the right."}],"ID":30488},{"Watched":false,"Name":"Exercise 10","Duration":"57s","ChapterTopicVideoID":28935,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.965","Text":"Let\u0027s dive into another exercise within monosaccharides have asymmetric centers."},{"Start":"00:04.965 ","End":"00:08.250","Text":"If an aldohexose has 4 chiral centers,"},{"Start":"00:08.250 ","End":"00:10.380","Text":"how many stereoisomers does it have?"},{"Start":"00:10.380 ","End":"00:12.180","Text":"Remember we gave a formula in general,"},{"Start":"00:12.180 ","End":"00:17.850","Text":"a molecule with n chiral centers have 2^n stereoisomers."},{"Start":"00:17.850 ","End":"00:20.505","Text":"If you have 4 chiral centers,"},{"Start":"00:20.505 ","End":"00:28.110","Text":"this means an aldohexose with 4 chiral centers has 2 to the power of 4 stereoisomers,"},{"Start":"00:28.110 ","End":"00:33.855","Text":"and that results in 16 total of stereoisomers."},{"Start":"00:33.855 ","End":"00:40.065","Text":"You can use this input any number if you have 5 chiral centers,"},{"Start":"00:40.065 ","End":"00:44.015","Text":"it\u0027s 2^5, which means 32,"},{"Start":"00:44.015 ","End":"00:45.885","Text":"because 16 times another 2."},{"Start":"00:45.885 ","End":"00:47.924","Text":"What is the idea?"},{"Start":"00:47.924 ","End":"00:49.470","Text":"2 times, 2 times 2 times 2,"},{"Start":"00:49.470 ","End":"00:51.435","Text":"4, 8,"},{"Start":"00:51.435 ","End":"00:58.240","Text":"16, so 2^4 is 16 stereoisomers because there are 4 chiral centers."}],"ID":30489},{"Watched":false,"Name":"Exercise 11","Duration":"3m 15s","ChapterTopicVideoID":28936,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:02.640","Text":"Hopefully you\u0027re ready to test your knowledge further on"},{"Start":"00:02.640 ","End":"00:04.950","Text":"monosaccharides have asymmetric centers."},{"Start":"00:04.950 ","End":"00:07.540","Text":"Which statement is false?"},{"Start":"00:07.540 ","End":"00:10.355","Text":"A, of the 16 possible aldohexoses,"},{"Start":"00:10.355 ","End":"00:14.225","Text":"8 and D forms and 8 are L. B,"},{"Start":"00:14.225 ","End":"00:18.205","Text":"most of the hexoses of living organisms are L isomers."},{"Start":"00:18.205 ","End":"00:23.715","Text":"C, the structures of the D stereoisomers have 3-6 carbon atoms."},{"Start":"00:23.715 ","End":"00:26.460","Text":"D, the carbons of a sugar are numbered"},{"Start":"00:26.460 ","End":"00:29.820","Text":"beginning at the end of the chain nears the carbonyl group."},{"Start":"00:29.820 ","End":"00:35.025","Text":"E, each of the 8 D-aldohexoses has its own name."},{"Start":"00:35.025 ","End":"00:40.130","Text":"Let\u0027s go again. Of the 16 possible aldohexoses"},{"Start":"00:40.130 ","End":"00:43.900","Text":"8 are D forms and 8 are L. Let\u0027s try to remember."},{"Start":"00:43.900 ","End":"00:46.055","Text":"Hexoses, that means 6,"},{"Start":"00:46.055 ","End":"00:53.780","Text":"and we know that it has 4 carbon chiral groups which means it was 2^4."},{"Start":"00:53.780 ","End":"00:56.081","Text":"So there are 16 possible aldohexoses."},{"Start":"00:56.081 ","End":"00:57.555","Text":"This is true,"},{"Start":"00:57.555 ","End":"01:06.315","Text":"and it was mentioned the 8 are D forms and 8 are L with a D being dextro and L,"},{"Start":"01:06.315 ","End":"01:10.340","Text":"levo, meaning it\u0027s on the left,"},{"Start":"01:10.340 ","End":"01:13.700","Text":"a hydroxyl group versus the D forms."},{"Start":"01:13.700 ","End":"01:15.374","Text":"This seems true. Therefore,"},{"Start":"01:15.374 ","End":"01:18.350","Text":"it\u0027s not our answer because we\u0027re looking for what is false."},{"Start":"01:18.350 ","End":"01:23.270","Text":"Let\u0027s go to B. Most of the hexoses of living organisms are L isomers."},{"Start":"01:23.270 ","End":"01:30.905","Text":"We actually mentioned L arabinose as an example of an L isomer that is found."},{"Start":"01:30.905 ","End":"01:35.150","Text":"But we mentioned that most of them are D isomers."},{"Start":"01:35.150 ","End":"01:38.025","Text":"D glucose, like dextrose."},{"Start":"01:38.025 ","End":"01:42.530","Text":"This seems it would be our right answer because it\u0027s false,"},{"Start":"01:42.530 ","End":"01:43.955","Text":"but let\u0027s verify the other ones."},{"Start":"01:43.955 ","End":"01:48.815","Text":"C, the structures of the D stereoisomers have 3-6 carbon atoms."},{"Start":"01:48.815 ","End":"01:52.640","Text":"If you remember that figure where we showed the 8 different aldohexoses,"},{"Start":"01:52.640 ","End":"01:56.505","Text":"and the 8 of D forms and the 8 of L forms,"},{"Start":"01:56.505 ","End":"02:00.350","Text":"we mentioned that they all have 3-6 carbon atoms."},{"Start":"02:00.350 ","End":"02:02.300","Text":"We have those that have 3 carbon atoms."},{"Start":"02:02.300 ","End":"02:07.890","Text":"Those are the most simple monosaccharides that are actually the trioses,"},{"Start":"02:07.890 ","End":"02:09.045","Text":"and then we have 4 carbons,"},{"Start":"02:09.045 ","End":"02:10.920","Text":"5 carbons, and 6 carbon atoms."},{"Start":"02:10.920 ","End":"02:12.462","Text":"This seems like a true statement."},{"Start":"02:12.462 ","End":"02:13.740","Text":"Therefore this again,"},{"Start":"02:13.740 ","End":"02:15.480","Text":"doesn\u0027t seem like our answer."},{"Start":"02:15.480 ","End":"02:18.710","Text":"D, the carbons of the sugar are numbered beginning"},{"Start":"02:18.710 ","End":"02:21.950","Text":"at the end of the chain nearest the carbonyl group."},{"Start":"02:21.950 ","End":"02:26.165","Text":"The carbonyl group is the group that the carbon has a double bond with the O,"},{"Start":"02:26.165 ","End":"02:32.486","Text":"and when we saw the numbering it was numbering from this direction on therefore,"},{"Start":"02:32.486 ","End":"02:34.535","Text":"this seems like a true statement as well."},{"Start":"02:34.535 ","End":"02:36.410","Text":"The carbons of sugars are numbered beginning at"},{"Start":"02:36.410 ","End":"02:38.570","Text":"the end of the chain nearest the carbonyl group."},{"Start":"02:38.570 ","End":"02:40.555","Text":"This is not our false statement."},{"Start":"02:40.555 ","End":"02:44.030","Text":"Each of the 8 D-aldohexoses has its own name."},{"Start":"02:44.030 ","End":"02:49.515","Text":"We mentioned this and actually stated some names."},{"Start":"02:49.515 ","End":"02:51.210","Text":"This is true as well."},{"Start":"02:51.210 ","End":"02:53.825","Text":"Therefore, it\u0027s not our answer and that leaves us with B."},{"Start":"02:53.825 ","End":"02:55.430","Text":"This is a false statement."},{"Start":"02:55.430 ","End":"02:56.885","Text":"What would make it true?"},{"Start":"02:56.885 ","End":"03:03.300","Text":"The correct statement is most of the hexoses of living organisms are D isomers."},{"Start":"03:03.300 ","End":"03:05.270","Text":"The statement that is false is B,"},{"Start":"03:05.270 ","End":"03:07.040","Text":"and that was our answer here,"},{"Start":"03:07.040 ","End":"03:11.228","Text":"and we can correct this by changing L isomers to D isomers."},{"Start":"03:11.228 ","End":"03:15.749","Text":"Most of the hexoses of living organisms are D isomers."}],"ID":30490},{"Watched":false,"Name":"Exercise 12","Duration":"1m 32s","ChapterTopicVideoID":28937,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.200","Text":"Ready for another exercise within monosaccharides have asymmetric centers,"},{"Start":"00:04.200 ","End":"00:06.975","Text":"hopefully you are, because here we go."},{"Start":"00:06.975 ","End":"00:08.640","Text":"What are epimers?"},{"Start":"00:08.640 ","End":"00:15.180","Text":"Epimers are sugars that differ only in the configuration around 1 carbon atom,"},{"Start":"00:15.180 ","End":"00:19.250","Text":"so you can have 2 sugars that differ only in"},{"Start":"00:19.250 ","End":"00:23.750","Text":"the configuration around 1 carbon atom and that will represent an epimer,"},{"Start":"00:23.750 ","End":"00:27.275","Text":"for example, you have D-glucose."},{"Start":"00:27.275 ","End":"00:31.665","Text":"Now, D-glucose has an epimer at C-2,"},{"Start":"00:31.665 ","End":"00:35.160","Text":"this changes orientation and reverses,"},{"Start":"00:35.160 ","End":"00:39.680","Text":"so now the hydroxyl group OH is on the left and the hydrogen group is on the right,"},{"Start":"00:39.680 ","End":"00:45.365","Text":"and that turns the D-glucose into a mannose."},{"Start":"00:45.365 ","End":"00:50.000","Text":"See, this is an epimer at C-2 of glucose,"},{"Start":"00:50.000 ","End":"00:53.990","Text":"glucose and mannose are epimers of each other,"},{"Start":"00:53.990 ","End":"00:57.295","Text":"while you have another example,"},{"Start":"00:57.295 ","End":"00:59.515","Text":"the stereochemistry, in this case,"},{"Start":"00:59.515 ","End":"01:01.070","Text":"it\u0027s different at C-2,"},{"Start":"01:01.070 ","End":"01:03.380","Text":"the stereochemistry of these 2 epimers,"},{"Start":"01:03.380 ","End":"01:07.880","Text":"D-galactose and D-glucose are different at C-4 where C-4,"},{"Start":"01:07.880 ","End":"01:12.275","Text":"you see the hydrogen is on the right and galactose hydroxyl on the left,"},{"Start":"01:12.275 ","End":"01:13.800","Text":"opposite of glucose,"},{"Start":"01:13.800 ","End":"01:19.190","Text":"so this is an epimer of D-glucose at C-4,"},{"Start":"01:19.190 ","End":"01:26.540","Text":"so epimers are 2 sugars that differ only in the configuration around 1 carbon atom,"},{"Start":"01:26.540 ","End":"01:31.920","Text":"or these are epimers of each other."}],"ID":30491},{"Watched":false,"Name":"Cyclic Structures Part 1","Duration":"10m 59s","ChapterTopicVideoID":28939,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.170 ","End":"00:04.950","Text":"We\u0027ve been covering topics within the chapter of carbohydrates,"},{"Start":"00:04.950 ","End":"00:07.900","Text":"and now we are going to talk about cyclic structures,"},{"Start":"00:07.900 ","End":"00:11.070","Text":"which we mentioned in the previous lessons."},{"Start":"00:11.070 ","End":"00:16.170","Text":"In this section, we will learn about hemiacetals and hemiketals,"},{"Start":"00:16.170 ","End":"00:18.495","Text":"pyranoses and furanoses,"},{"Start":"00:18.495 ","End":"00:19.760","Text":"and the terms anomers,"},{"Start":"00:19.760 ","End":"00:22.940","Text":"anomeric carbon, and mutarotation."},{"Start":"00:22.940 ","End":"00:26.540","Text":"Now we will split this section into a couple of parts."},{"Start":"00:26.540 ","End":"00:29.330","Text":"In Part 1 of cyclic structures,"},{"Start":"00:29.330 ","End":"00:31.995","Text":"we will learn about hemiacetals,"},{"Start":"00:31.995 ","End":"00:34.950","Text":"hemiketals, pyranoses and furanoses,"},{"Start":"00:34.950 ","End":"00:39.445","Text":"and the term anomers and define anomers."},{"Start":"00:39.445 ","End":"00:43.370","Text":"The common monosaccharides have cyclic structures."},{"Start":"00:43.370 ","End":"00:47.210","Text":"For simplicity, we have thus far represented the structures of aldoses and"},{"Start":"00:47.210 ","End":"00:51.845","Text":"ketoses as straight chain molecules in the previous lesson."},{"Start":"00:51.845 ","End":"00:56.210","Text":"As a reminder, you can see the figures here that we introduced and talked about."},{"Start":"00:56.210 ","End":"01:03.380","Text":"This depicts the 3-6 carbon D- Aldoses and the 3-6 carbons structures,"},{"Start":"01:03.380 ","End":"01:07.745","Text":"linear structures of the D-ketosis but in reality,"},{"Start":"01:07.745 ","End":"01:11.065","Text":"in fact, in aqueous solution,"},{"Start":"01:11.065 ","End":"01:14.100","Text":"aldotetroses and all monosaccharides with"},{"Start":"01:14.100 ","End":"01:19.880","Text":"5 or more carbon atoms occur as cyclic structures, ring structures."},{"Start":"01:19.880 ","End":"01:23.225","Text":"In other words, in aqueous solutions,"},{"Start":"01:23.225 ","End":"01:29.080","Text":"when you have 5 or more carbons in the backbone of the carbohydrate,"},{"Start":"01:29.080 ","End":"01:36.680","Text":"these occur predominantly as circular structures in which the carbonyl group has"},{"Start":"01:36.680 ","End":"01:44.285","Text":"formed a covalent bond with the oxygen of a hydroxyl group along the chain."},{"Start":"01:44.285 ","End":"01:47.300","Text":"The formation of these ring structures is the result of"},{"Start":"01:47.300 ","End":"01:50.720","Text":"a general reaction between alcohols and aldehydes."},{"Start":"01:50.720 ","End":"01:54.020","Text":"Alcohols generally are the hydroxyl groups."},{"Start":"01:54.020 ","End":"01:57.945","Text":"They have OH or OOH,"},{"Start":"01:57.945 ","End":"02:00.075","Text":"this would be the alcohols."},{"Start":"02:00.075 ","End":"02:06.500","Text":"There\u0027s a general reaction between alcohols and aldehydes or ketones to"},{"Start":"02:06.500 ","End":"02:14.045","Text":"form derivatives called hemiacetals or hemiketals as you could see in the figure here."},{"Start":"02:14.045 ","End":"02:17.780","Text":"Hemiacetal and hemiketal alcohols react with"},{"Start":"02:17.780 ","End":"02:25.010","Text":"the carbonyl groups of aldehydes and ketones to form either for the aldehyde,"},{"Start":"02:25.010 ","End":"02:29.960","Text":"the hemiacetal, and with a ketone, the hemiketal respectively."},{"Start":"02:29.960 ","End":"02:32.555","Text":"Meaning when an alcohol combines with an aldose,"},{"Start":"02:32.555 ","End":"02:37.204","Text":"it results in a hemiacetal and when an alcohol binds with a ketone,"},{"Start":"02:37.204 ","End":"02:39.670","Text":"it forms the hemiketal."},{"Start":"02:39.670 ","End":"02:43.055","Text":"What you see here is the alcohol group."},{"Start":"02:43.055 ","End":"02:50.570","Text":"Either one, you have these combine so that now where you have this carbon,"},{"Start":"02:50.570 ","End":"02:53.345","Text":"the H associated here,"},{"Start":"02:53.345 ","End":"02:58.955","Text":"and then you have this remaining and the same idea happens here."},{"Start":"02:58.955 ","End":"03:05.665","Text":"The H associates with the oxygen and the O associates here."},{"Start":"03:05.665 ","End":"03:09.095","Text":"If a second alcohol molecule is added,"},{"Start":"03:09.095 ","End":"03:14.720","Text":"it produces the full acetal or ketal and the bond form is a glycosidic linkage."},{"Start":"03:14.720 ","End":"03:16.340","Text":"As you see here,"},{"Start":"03:16.340 ","End":"03:21.856","Text":"there is another alcohol that\u0027s added as you here,"},{"Start":"03:21.856 ","End":"03:26.915","Text":"and then you have this forming at full acetal with"},{"Start":"03:26.915 ","End":"03:32.670","Text":"release of water and this is a reversible reaction as is this."},{"Start":"03:32.670 ","End":"03:35.450","Text":"When the 2 molecules that react or monosaccharides,"},{"Start":"03:35.450 ","End":"03:39.035","Text":"the acetal or ketal formed is a disaccharide."},{"Start":"03:39.035 ","End":"03:42.230","Text":"The reaction with the first molecule,"},{"Start":"03:42.230 ","End":"03:44.765","Text":"alcohol creates an additional chiral center."},{"Start":"03:44.765 ","End":"03:48.620","Text":"See, you have this chiral center because"},{"Start":"03:48.620 ","End":"03:53.355","Text":"now it has the 4 bonds that are not mirror images,"},{"Start":"03:53.355 ","End":"03:56.465","Text":"so this is the carbonyl carbon,"},{"Start":"03:56.465 ","End":"03:57.977","Text":"the additional chiral center."},{"Start":"03:57.977 ","End":"03:59.660","Text":"Now you have a chiral center,"},{"Start":"03:59.660 ","End":"04:04.175","Text":"and because the alcohol can add to the front or the back,"},{"Start":"04:04.175 ","End":"04:06.305","Text":"either here or here,"},{"Start":"04:06.305 ","End":"04:10.335","Text":"it can result in 1 of either 2 stereo isomers."},{"Start":"04:10.335 ","End":"04:12.590","Text":"In this figure where you see the formation of"},{"Start":"04:12.590 ","End":"04:15.560","Text":"the hemiacetals is an hemiketals and aldehyde or ketone can"},{"Start":"04:15.560 ","End":"04:20.705","Text":"react with an alcohol and a 1:1 ratio to yield a hemiacetal or hemiketal respectively,"},{"Start":"04:20.705 ","End":"04:23.600","Text":"creating a new chiral center at the carbonyl carbon."},{"Start":"04:23.600 ","End":"04:28.265","Text":"Substitution of a second alcohol molecule produces an acetal or ketal."},{"Start":"04:28.265 ","End":"04:31.505","Text":"When the second alcohol is part of another sugar molecule,"},{"Start":"04:31.505 ","End":"04:35.195","Text":"the bond produced is a glycosidic bond."},{"Start":"04:35.195 ","End":"04:40.700","Text":"If you have 2 molecules that are actually instead of alcohol,"},{"Start":"04:40.700 ","End":"04:42.290","Text":"you have another aldehyde,"},{"Start":"04:42.290 ","End":"04:44.930","Text":"another carbohydrate, another monosaccharide,"},{"Start":"04:44.930 ","End":"04:49.955","Text":"you get a disaccharide versus a hemiacetal or a hemiketal."},{"Start":"04:49.955 ","End":"04:53.360","Text":"Now these contain an additional asymmetric carbon atom"},{"Start":"04:53.360 ","End":"04:56.480","Text":"and thus can exist in 2 stereo isomer forms."},{"Start":"04:56.480 ","End":"04:57.650","Text":"In other words, the addition of"},{"Start":"04:57.650 ","End":"05:00.380","Text":"the first alcohol molecule creates an additional chiral center,"},{"Start":"05:00.380 ","End":"05:02.048","Text":"the carbonyl carbon,"},{"Start":"05:02.048 ","End":"05:04.835","Text":"and because the alcohol can add in either of two ways,"},{"Start":"05:04.835 ","End":"05:08.480","Text":"attaching either to the front or the back of the carbonyl carbon,"},{"Start":"05:08.480 ","End":"05:09.890","Text":"the reaction can produce either of"},{"Start":"05:09.890 ","End":"05:13.430","Text":"two stereoisomer configurations denoted Alpha and Beta."},{"Start":"05:13.430 ","End":"05:15.260","Text":"If we\u0027re looking at this figure,"},{"Start":"05:15.260 ","End":"05:17.825","Text":"you have Alpha or Beta."},{"Start":"05:17.825 ","End":"05:21.842","Text":"Now again, if we look here, for example, D-glucose."},{"Start":"05:21.842 ","End":"05:26.135","Text":"This exists in solution as an intramolecular hemiacetal in which"},{"Start":"05:26.135 ","End":"05:33.940","Text":"the free hydroxyl group at C5 has reacted with aldehyde C1."},{"Start":"05:33.940 ","End":"05:37.970","Text":"Rendering the latter carbon asymmetric and"},{"Start":"05:37.970 ","End":"05:43.800","Text":"producing this hemiacetal because is like an alcohol."},{"Start":"05:43.800 ","End":"05:45.410","Text":"So if we look again here,"},{"Start":"05:45.410 ","End":"05:47.990","Text":"you have this OH."},{"Start":"05:47.990 ","End":"05:52.160","Text":"This is now a hemiacetal rendering the latter carbon asymmetric and"},{"Start":"05:52.160 ","End":"05:56.525","Text":"producing the two possible stereo isomers that you see here designated Alpha and Beta,"},{"Start":"05:56.525 ","End":"05:58.550","Text":"so you see the Alpha and Beta."},{"Start":"05:58.550 ","End":"06:00.110","Text":"As just mentioned, for example,"},{"Start":"06:00.110 ","End":"06:03.695","Text":"D-glucose, once it forms this hemiacetal,"},{"Start":"06:03.695 ","End":"06:09.530","Text":"it can actually exist in 1 or 2 isometric forms."},{"Start":"06:09.530 ","End":"06:13.040","Text":"Now, these two differ only in"},{"Start":"06:13.040 ","End":"06:17.375","Text":"the stereochemistry around the hemiacetal carbon right here."},{"Start":"06:17.375 ","End":"06:24.105","Text":"The interconversion of Alpha and Beta anomers is called mutarotation."},{"Start":"06:24.105 ","End":"06:30.110","Text":"These two anomers, when you have this interconversion between Alpha and Beta,"},{"Start":"06:30.110 ","End":"06:33.550","Text":"it is called mutarotation,"},{"Start":"06:33.550 ","End":"06:36.020","Text":"like rotation between the mutations,"},{"Start":"06:36.020 ","End":"06:38.695","Text":"mutation between the anomers."},{"Start":"06:38.695 ","End":"06:41.250","Text":"Now if the OH,"},{"Start":"06:41.250 ","End":"06:45.705","Text":"the carboxyl and carbonyl groups are on the same molecule,"},{"Start":"06:45.705 ","End":"06:49.185","Text":"a 5 or 6 membered ring results."},{"Start":"06:49.185 ","End":"06:55.010","Text":"These 6 membered ring compounds are called parenoses or pyranoses because"},{"Start":"06:55.010 ","End":"06:58.425","Text":"they resemble the 6 membered ring compound pyran"},{"Start":"06:58.425 ","End":"07:01.140","Text":"or a parent and that\u0027s what you see here."},{"Start":"07:01.140 ","End":"07:03.300","Text":"A 6-membered ring."},{"Start":"07:03.300 ","End":"07:08.270","Text":"Here, you have a 6-membered carbonyl structure."},{"Start":"07:08.270 ","End":"07:11.720","Text":"These resemble these and therefore,"},{"Start":"07:11.720 ","End":"07:15.845","Text":"the term pyranose has been applied to these."},{"Start":"07:15.845 ","End":"07:19.460","Text":"The systematic names for the two ring forms of"},{"Start":"07:19.460 ","End":"07:24.440","Text":"D-glucose are Alpha D-glucose pyranose and Beta D-glucose pyranose."},{"Start":"07:24.440 ","End":"07:27.770","Text":"Alpha and Beta configurations because you have"},{"Start":"07:27.770 ","End":"07:34.167","Text":"the two different configurations that differ solely around the carbonyl carbon,"},{"Start":"07:34.167 ","End":"07:35.464","Text":"so the differences here."},{"Start":"07:35.464 ","End":"07:39.265","Text":"Remember the hydroxyl group are what differ,"},{"Start":"07:39.265 ","End":"07:44.550","Text":"so Alpha and Beta and they generally resemble this ring structure,"},{"Start":"07:44.550 ","End":"07:51.340","Text":"the pyran, so they are called as such when they are in ring form."},{"Start":"07:51.340 ","End":"07:54.110","Text":"Aldohexoses also exist."},{"Start":"07:54.110 ","End":"07:57.110","Text":"The hexose that refers to"},{"Start":"07:57.110 ","End":"08:01.985","Text":"the 5-membered rings and these which because they resemble the 5-membered ring,"},{"Start":"08:01.985 ","End":"08:05.330","Text":"compound purine, are called furanoses."},{"Start":"08:05.330 ","End":"08:08.730","Text":"Furan, this is a 5-membered ring."},{"Start":"08:08.730 ","End":"08:10.215","Text":"Here you have 1,"},{"Start":"08:10.215 ","End":"08:12.090","Text":"2, 3, 4, 5, 6."},{"Start":"08:12.090 ","End":"08:14.475","Text":"Here you have 1, 2, 3, 4, 5."},{"Start":"08:14.475 ","End":"08:19.335","Text":"These 5-membered rings of these carbs are"},{"Start":"08:19.335 ","End":"08:26.960","Text":"deemed furanoses because of their resemblance to the ring molecule structure furan."},{"Start":"08:26.960 ","End":"08:30.710","Text":"Similarly to the glucose pyranose,"},{"Start":"08:30.710 ","End":"08:35.670","Text":"you have a furanose like the fructofuranose here."},{"Start":"08:35.670 ","End":"08:38.030","Text":"It also has these anomers,"},{"Start":"08:38.030 ","End":"08:39.470","Text":"the Alpha and Beta,"},{"Start":"08:39.470 ","End":"08:45.387","Text":"and the interchange between them is what it\u0027s called mutarotation."},{"Start":"08:45.387 ","End":"08:49.580","Text":"So that there\u0027s a similar idea in how these structures and reactions occur."},{"Start":"08:49.580 ","End":"08:54.170","Text":"However, the 6-membered aldopyranose ring is much more stable than"},{"Start":"08:54.170 ","End":"09:00.000","Text":"aldofuranose ring and therefore predominates in aldohexose solutions."},{"Start":"09:00.000 ","End":"09:05.555","Text":"Only aldose is having 5 or more carbon atoms can form the pyranose rings."},{"Start":"09:05.555 ","End":"09:08.725","Text":"Again, we have the 5-carbon ring,"},{"Start":"09:08.725 ","End":"09:13.690","Text":"which are called furanoses and the 6 that are called pyranoses."},{"Start":"09:13.690 ","End":"09:18.740","Text":"Now, generally this figure is a representation of"},{"Start":"09:18.740 ","End":"09:25.290","Text":"a Howard perspective formula of the pyranose and the furanoses rings and the edges."},{"Start":"09:25.290 ","End":"09:30.905","Text":"The rings that are supposedly closest to us are represented by these bold lines."},{"Start":"09:30.905 ","End":"09:33.320","Text":"Hydroxyl groups below the plane of the ring in"},{"Start":"09:33.320 ","End":"09:39.210","Text":"these Howard perspectives would appear at the right side of a Fischer projection."},{"Start":"09:39.210 ","End":"09:46.580","Text":"This is just another different way to show the structure of molecules."},{"Start":"09:46.580 ","End":"09:48.965","Text":"Ketohexoses as shown here,"},{"Start":"09:48.965 ","End":"09:52.430","Text":"also occur in Alpha and Beta anomeric forms."},{"Start":"09:52.430 ","End":"09:54.650","Text":"Similar to aldohexose."},{"Start":"09:54.650 ","End":"10:02.630","Text":"In these compounds that the hydroxyl group at C5 or C6 react with the keto group at C2,"},{"Start":"10:02.630 ","End":"10:07.555","Text":"forming a furanose or pyranose ring containing a hemiketal linkage,"},{"Start":"10:07.555 ","End":"10:09.350","Text":"so that happens here."},{"Start":"10:09.350 ","End":"10:14.705","Text":"This results, this hemiketal linkage results in example fructose,"},{"Start":"10:14.705 ","End":"10:17.060","Text":"D-fructose readily forms the furanose ring."},{"Start":"10:17.060 ","End":"10:20.240","Text":"The more common anomer of this sugar in"},{"Start":"10:20.240 ","End":"10:25.040","Text":"combined forms or in derivatives is Beta D-fructofuranose,"},{"Start":"10:25.040 ","End":"10:32.670","Text":"so this one is the anomer that is more common."},{"Start":"10:36.830 ","End":"10:41.540","Text":"With this, we completed Part 1 of cyclic structures within the chapter of"},{"Start":"10:41.540 ","End":"10:45.665","Text":"carbohydrates and we learned about hemiacetals and hemiketals,"},{"Start":"10:45.665 ","End":"10:48.795","Text":"pyranoses and furanoses, and anomers."},{"Start":"10:48.795 ","End":"10:52.783","Text":"In part 2, we will further talk about cyclic structures,"},{"Start":"10:52.783 ","End":"10:58.620","Text":"these different forms of pyranose and furanoses and additional topics."}],"ID":30492},{"Watched":false,"Name":"Cyclic Structures Part 2","Duration":"6m 32s","ChapterTopicVideoID":28940,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.480 ","End":"00:05.365","Text":"Welcome back to cyclic structures within the chapter on carbohydrates."},{"Start":"00:05.365 ","End":"00:08.260","Text":"This is the second part of cyclic structures."},{"Start":"00:08.260 ","End":"00:12.444","Text":"In this section we will learn about hemiacetals and hemiketal,"},{"Start":"00:12.444 ","End":"00:13.910","Text":"which we talked about in Part 1,"},{"Start":"00:13.910 ","End":"00:16.105","Text":"and now we\u0027ll add information."},{"Start":"00:16.105 ","End":"00:17.770","Text":"We\u0027ll talk about the terms anomers,"},{"Start":"00:17.770 ","End":"00:22.030","Text":"which we introduced in Part 1 and anomeric carbon and mutarotation,"},{"Start":"00:22.030 ","End":"00:25.855","Text":"and we will introduce the Haworth perspective formulas."},{"Start":"00:25.855 ","End":"00:30.310","Text":"\"Isomeric forms of monosaccharides that differ only in their configuration"},{"Start":"00:30.310 ","End":"00:35.575","Text":"about the hemiacetal or hemiketal carbon atoms are called anomers."},{"Start":"00:35.575 ","End":"00:41.105","Text":"The hemiacetal or carbonyl carbon atom is called the anomeric carbon."},{"Start":"00:41.105 ","End":"00:43.215","Text":"This term we\u0027ve gone over already,"},{"Start":"00:43.215 ","End":"00:46.550","Text":"but now we have this term, anomeric carbon.\""},{"Start":"00:46.550 ","End":"00:50.315","Text":"This is the hemiacetal carbon or carbonyl carbon,"},{"Start":"00:50.315 ","End":"00:53.425","Text":"around which the variation occurs."},{"Start":"00:53.425 ","End":"00:55.340","Text":"\"The Alpha and Beta anomers of"},{"Start":"00:55.340 ","End":"00:59.600","Text":"D-glucose interconvert in aqueous solution by a process called"},{"Start":"00:59.600 ","End":"01:08.975","Text":"mutarotation,\" in which 1 ring form opens here into the linear form,"},{"Start":"01:08.975 ","End":"01:12.200","Text":"then closes again to produce the other anomer."},{"Start":"01:12.200 ","End":"01:18.440","Text":"This opens and then can reclose in this formation."},{"Start":"01:18.440 ","End":"01:24.110","Text":"Thus, a solution of alpha D-glucose and a solution of Beta D-glucose"},{"Start":"01:24.110 ","End":"01:30.605","Text":"eventually form identical equilibrium mixtures having identical optical properties."},{"Start":"01:30.605 ","End":"01:31.865","Text":"Now the optical properties,"},{"Start":"01:31.865 ","End":"01:33.050","Text":"the significance of this,"},{"Start":"01:33.050 ","End":"01:34.880","Text":"this is a matter of physics,"},{"Start":"01:34.880 ","End":"01:38.195","Text":"is again the idea of the reflection,"},{"Start":"01:38.195 ","End":"01:42.920","Text":"of light and such based on the molecular structure."},{"Start":"01:42.920 ","End":"01:45.785","Text":"That is how you can see things."},{"Start":"01:45.785 ","End":"01:50.075","Text":"If you shine a light on a certain mirror and it has different angles,"},{"Start":"01:50.075 ","End":"01:51.500","Text":"it will reflect differently."},{"Start":"01:51.500 ","End":"01:54.665","Text":"This is something that allows for"},{"Start":"01:54.665 ","End":"01:58.970","Text":"visual optical differences and therefore are the optical properties."},{"Start":"01:58.970 ","End":"02:06.570","Text":"\"This mixture consists of about 1/3 alpha D-glucose, 2/3 Beta D-glucose,"},{"Start":"02:06.570 ","End":"02:10.670","Text":"and very small amounts of the linear form and the"},{"Start":"02:10.670 ","End":"02:15.655","Text":"5 membered ring glucose pyranose forms.\""},{"Start":"02:15.655 ","End":"02:19.170","Text":"We said that these are more common."},{"Start":"02:19.170 ","End":"02:22.910","Text":"We do see here that it is more plentiful."},{"Start":"02:22.910 ","End":"02:27.530","Text":"The presence of these aren\u0027t twice as much as the alpha D-glucose."},{"Start":"02:27.530 ","End":"02:31.175","Text":"This mixture in actuality will consist of"},{"Start":"02:31.175 ","End":"02:36.469","Text":"about 2/3 Beta D-glucose and very small amounts of the linear form,"},{"Start":"02:36.469 ","End":"02:40.685","Text":"and a 5 membered ring glucose pyranose form."},{"Start":"02:40.685 ","End":"02:45.530","Text":"Cyclic sugar structures are more accurately represented in Haworth perspective formulas."},{"Start":"02:45.530 ","End":"02:48.425","Text":"That\u0027s what I mentioned a little bit earlier, just touched up on it,"},{"Start":"02:48.425 ","End":"02:50.950","Text":"like those in this figure,"},{"Start":"02:50.950 ","End":"02:56.165","Text":"and thus are commonly used to show the stereochemistry of ring forms of monosaccharides."},{"Start":"02:56.165 ","End":"03:00.394","Text":"However, the 6 membered pyranose ring is not planar,"},{"Start":"03:00.394 ","End":"03:02.225","Text":"as Haworth perspective suggests,"},{"Start":"03:02.225 ","End":"03:06.260","Text":"it is tilted to make its plane almost perpendicular to that of"},{"Start":"03:06.260 ","End":"03:11.390","Text":"the paper with the bonds closest to the observer drawn thicker than those farther away,"},{"Start":"03:11.390 ","End":"03:17.630","Text":"but tends to assume either of 2 chair conformations as seen here."},{"Start":"03:17.630 ","End":"03:19.640","Text":"Looking at this figure,"},{"Start":"03:19.640 ","End":"03:22.490","Text":"we have the alpha D-glucose pyranose."},{"Start":"03:22.490 ","End":"03:23.840","Text":"You have the axis."},{"Start":"03:23.840 ","End":"03:28.310","Text":"What we see here is the 2 chair forms of the pyranose ring."},{"Start":"03:28.310 ","End":"03:34.175","Text":"Substituents on the ring carbons may be either Axial, AX,"},{"Start":"03:34.175 ","End":"03:43.335","Text":"projecting parallel to the vertical axis through the ring or equatorial,"},{"Start":"03:43.335 ","End":"03:45.870","Text":"EQ, like the equator."},{"Start":"03:45.870 ","End":"03:48.995","Text":"This is a horizontal thing,"},{"Start":"03:48.995 ","End":"03:54.440","Text":"projecting roughly perpendicular in 90 degrees to this axis."},{"Start":"03:54.440 ","End":"03:58.070","Text":"Basically like 90 degrees parallel,"},{"Start":"03:58.070 ","End":"04:03.335","Text":"if we could think of this to the ground that would be parallel to the ground."},{"Start":"04:03.335 ","End":"04:08.240","Text":"conformers as these are not readily interconvertible without breaking the ring."},{"Start":"04:08.240 ","End":"04:12.980","Text":"However, when the molecule is stretched by atomic force microscopy and"},{"Start":"04:12.980 ","End":"04:19.610","Text":"input of energy is applied the interconversion of the chair forms can occur."},{"Start":"04:19.610 ","End":"04:22.790","Text":"Generally substituents in the equatorial positions"},{"Start":"04:22.790 ","End":"04:25.955","Text":"are less sterically hindered by neighboring substituents,"},{"Start":"04:25.955 ","End":"04:32.100","Text":"and conform with bulky substituents in equatorial positions are favorite."},{"Start":"04:32.100 ","End":"04:38.990","Text":"The take home message is the orientation and the organization and the structure has"},{"Start":"04:38.990 ","End":"04:47.365","Text":"more significance in the 3-dimensions where you have it either vertical or horizontal."},{"Start":"04:47.365 ","End":"04:54.395","Text":"The hydrogen here would be AX because it is vertical it is up versus the OH,"},{"Start":"04:54.395 ","End":"05:00.200","Text":"which is more of sticking to the side, it is equatorial."},{"Start":"05:00.200 ","End":"05:06.305","Text":"This way depicts the directionality of these molecules is and this way,"},{"Start":"05:06.305 ","End":"05:08.510","Text":"the Haworth perspective formula,"},{"Start":"05:08.510 ","End":"05:14.945","Text":"this bolder line shows that this is towards us and this is farther away from us."},{"Start":"05:14.945 ","End":"05:16.790","Text":"Now if we recall from early on in the course,"},{"Start":"05:16.790 ","End":"05:18.560","Text":"the 2 conformations of a molecule are"},{"Start":"05:18.560 ","End":"05:21.440","Text":"interconvertible without the breakage of covalent bonds,"},{"Start":"05:21.440 ","End":"05:25.970","Text":"whereas 2 configurations can be interconverted only by breaking a covalent bond."},{"Start":"05:25.970 ","End":"05:29.390","Text":"For example, in the case of Alpha and Beta configurations,"},{"Start":"05:29.390 ","End":"05:33.260","Text":"the bond involving the ring oxygen atom has to be broken."},{"Start":"05:33.260 ","End":"05:37.580","Text":"But interconversion of the 2 chair forms which are conformers,"},{"Start":"05:37.580 ","End":"05:40.370","Text":"does not require bond breakage and does not change"},{"Start":"05:40.370 ","End":"05:43.670","Text":"configurations at any of the ring carbons."},{"Start":"05:43.670 ","End":"05:48.755","Text":"Bottom line is that this ring is not planar, it\u0027s not flat."},{"Start":"05:48.755 ","End":"05:52.220","Text":"Even these groups, they have an orientation and"},{"Start":"05:52.220 ","End":"05:56.720","Text":"a confirmation so that when this is towards us,"},{"Start":"05:56.720 ","End":"06:00.365","Text":"and this is away you could see the oxygen here is up,"},{"Start":"06:00.365 ","End":"06:02.720","Text":"here it\u0027s down, you see acts,"},{"Start":"06:02.720 ","End":"06:04.502","Text":"that means it\u0027s vertical,"},{"Start":"06:04.502 ","End":"06:05.990","Text":"this is more horizontal."},{"Start":"06:05.990 ","End":"06:07.640","Text":"This is different."},{"Start":"06:07.640 ","End":"06:09.230","Text":"This is up here."},{"Start":"06:09.230 ","End":"06:12.230","Text":"The specific 3-dimensional structure\u0027s confirmations of"},{"Start":"06:12.230 ","End":"06:16.280","Text":"the monosaccharide units are important in determining the biological properties,"},{"Start":"06:16.280 ","End":"06:18.755","Text":"and functions of some polysaccharides."},{"Start":"06:18.755 ","End":"06:23.518","Text":"With this, we completed the lesson on cyclic structures within carbohydrates,"},{"Start":"06:23.518 ","End":"06:25.985","Text":"and we talked about hemiacetals and hemiketal,"},{"Start":"06:25.985 ","End":"06:29.240","Text":"pyranoses and furanoses and introduced the terms anomers,"},{"Start":"06:29.240 ","End":"06:33.090","Text":"anomeric carbon, and mutarotation."}],"ID":30493},{"Watched":false,"Name":"Exercise 13","Duration":"1m 17s","ChapterTopicVideoID":28941,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.400","Text":"Let\u0027s work on some exercises within covering the lesson on cyclic structures."},{"Start":"00:05.400 ","End":"00:09.420","Text":"First exercise, define hemiacetals and hemiketals."},{"Start":"00:09.420 ","End":"00:11.850","Text":"An aqueous solution, all monosaccharides with"},{"Start":"00:11.850 ","End":"00:18.540","Text":"5 or more carbon atoms in the backbone occur as cyclic structures,"},{"Start":"00:18.540 ","End":"00:21.570","Text":"as rings as circular structures."},{"Start":"00:21.570 ","End":"00:26.235","Text":"In which the carbonyl group has formed a covalent bond"},{"Start":"00:26.235 ","End":"00:31.650","Text":"and it\u0027s covalently bound with oxygen of a hydroxyl group along the chain."},{"Start":"00:31.650 ","End":"00:35.520","Text":"The formation of cyclic structures is the result of"},{"Start":"00:35.520 ","End":"00:39.885","Text":"a general reaction between alcohols and aldehydes,"},{"Start":"00:39.885 ","End":"00:46.800","Text":"the OH and COO"},{"Start":"00:46.800 ","End":"00:53.540","Text":"or ketones to form derivatives called hemiacetals or hemiketals."},{"Start":"00:53.540 ","End":"00:59.330","Text":"Alcohols react with the carbonyl groups of aldehyde to form hemiacetals."},{"Start":"00:59.330 ","End":"01:02.720","Text":"Meaning when an alcohol combines with an aldose,"},{"Start":"01:02.720 ","End":"01:05.710","Text":"it results in hemiacetals."},{"Start":"01:05.710 ","End":"01:10.240","Text":"When alcohols react with the carbonyl groups of ketones, they form hemiketals."},{"Start":"01:10.240 ","End":"01:13.550","Text":"Meaning when alcohol binds with a ketose,"},{"Start":"01:13.550 ","End":"01:15.900","Text":"the hemiketal is formed."}],"ID":30494},{"Watched":false,"Name":"Exercise 14","Duration":"1m 15s","ChapterTopicVideoID":28942,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.684","Text":"We have another exercise within cyclic structures."},{"Start":"00:04.684 ","End":"00:08.890","Text":"Define and differentiate between pyranoses and furanoses."},{"Start":"00:08.890 ","End":"00:11.695","Text":"If the OH, the alcohol,"},{"Start":"00:11.695 ","End":"00:14.520","Text":"and carbonyl groups are on the same molecule,"},{"Start":"00:14.520 ","End":"00:17.160","Text":"a 5 or 6 membered ring results."},{"Start":"00:17.160 ","End":"00:20.235","Text":"If it\u0027s on the same carbohydrate molecule,"},{"Start":"00:20.235 ","End":"00:22.005","Text":"this ring can result."},{"Start":"00:22.005 ","End":"00:26.400","Text":"Now, these 6-membered ring compounds are called pyranoses."},{"Start":"00:26.400 ","End":"00:27.915","Text":"When you have 6-membered rings,"},{"Start":"00:27.915 ","End":"00:34.545","Text":"it\u0027s pyranoses as it resembles the 6-membered ring compound, pyran."},{"Start":"00:34.545 ","End":"00:40.790","Text":"Aldohexoses also exist in cyclic forms having 5-membered rings,"},{"Start":"00:40.790 ","End":"00:44.640","Text":"which because they resemble the 5-membered ring compound furan"},{"Start":"00:44.640 ","End":"00:51.765","Text":", are called furanoses."},{"Start":"00:51.765 ","End":"00:54.945","Text":"6-membered ring, pyranose."},{"Start":"00:54.945 ","End":"00:57.330","Text":"5-membered ring, furanose."},{"Start":"00:57.330 ","End":"01:00.990","Text":"However, the 6-membered aldopyranose ring is"},{"Start":"01:00.990 ","End":"01:04.838","Text":"much more stable than the aldofuranose ring,"},{"Start":"01:04.838 ","End":"01:08.940","Text":"and predominates therefore in aldohexose solutions."},{"Start":"01:08.940 ","End":"01:15.780","Text":"Only aldoses having 5 or more carbon atoms can form pyranose rings."}],"ID":30495},{"Watched":false,"Name":"Exercise 15","Duration":"1m 2s","ChapterTopicVideoID":28938,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:02.820","Text":"Let\u0027s see what else we learned in the lesson on"},{"Start":"00:02.820 ","End":"00:05.609","Text":"cyclic structures and dive into another exercise."},{"Start":"00:05.609 ","End":"00:07.620","Text":"Define the terms anomer,"},{"Start":"00:07.620 ","End":"00:10.605","Text":"anomeric carbon, and mutarotation."},{"Start":"00:10.605 ","End":"00:15.330","Text":"Isometric forms of monosaccharides that differ only in their configuration about"},{"Start":"00:15.330 ","End":"00:20.610","Text":"the hemiacetal or hemiketal carbon atom are called anomers."},{"Start":"00:20.610 ","End":"00:26.430","Text":"The hemiacetal or carbonyl carbon atom is called the anomeric carbon."},{"Start":"00:26.430 ","End":"00:29.460","Text":"Therefore, the carbon at which the change,"},{"Start":"00:29.460 ","End":"00:32.505","Text":"the variation between the anomers,"},{"Start":"00:32.505 ","End":"00:34.425","Text":"is the anomeric carbon."},{"Start":"00:34.425 ","End":"00:39.305","Text":"The process by which Alpha and Beta anomers of D-glucose, for example,"},{"Start":"00:39.305 ","End":"00:41.885","Text":"or any Alpha, Beta anomers,"},{"Start":"00:41.885 ","End":"00:46.520","Text":"interconvert in aqueous solution is called mutarotation."},{"Start":"00:46.520 ","End":"00:50.450","Text":"In this case, what you have is 1 ring form that opens briefly into"},{"Start":"00:50.450 ","End":"00:55.010","Text":"the linear form and then closes again to produce the other anomer."},{"Start":"00:55.010 ","End":"00:57.920","Text":"If you want a visual representation,"},{"Start":"00:57.920 ","End":"01:02.070","Text":"this was introduced in the lesson with figures."}],"ID":30496},{"Watched":false,"Name":"Hexose derivatives in organisms","Duration":"8m 11s","ChapterTopicVideoID":28944,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:03.134","Text":"Welcome back to the chapter on carbohydrates,"},{"Start":"00:03.134 ","End":"00:06.780","Text":"where we are now going to talk about hexose derivatives in organisms."},{"Start":"00:06.780 ","End":"00:10.500","Text":"To me, this is now taking this information,"},{"Start":"00:10.500 ","End":"00:11.820","Text":"the material that we learned,"},{"Start":"00:11.820 ","End":"00:12.960","Text":"the technical stuff,"},{"Start":"00:12.960 ","End":"00:16.200","Text":"and apply it to biology."},{"Start":"00:16.200 ","End":"00:19.320","Text":"This is where the meat of the stuff comes in."},{"Start":"00:19.320 ","End":"00:21.990","Text":"In this section, you will learn about various derivatives"},{"Start":"00:21.990 ","End":"00:24.779","Text":"of simple sugars that are found in organisms."},{"Start":"00:24.779 ","End":"00:26.730","Text":"Why is this relevant?"},{"Start":"00:26.730 ","End":"00:31.410","Text":"In addition to simple hexoses such as glucose, galactose, and mannose,"},{"Start":"00:31.410 ","End":"00:34.665","Text":"there are a number of sugar derivatives in which"},{"Start":"00:34.665 ","End":"00:40.670","Text":"a hydroxyl group in the parent compound is replaced with another molecule,"},{"Start":"00:40.670 ","End":"00:45.220","Text":"or a carbon atom is oxidized to a carboxyl group."},{"Start":"00:45.220 ","End":"00:50.090","Text":"Because the cyclic and linear forms of aldoses and ketoses interconvert,"},{"Start":"00:50.090 ","End":"00:53.900","Text":"these sugars undergo reactions typical of aldehydes and ketones,"},{"Start":"00:53.900 ","End":"00:55.925","Text":"which we will cover in this lesson."},{"Start":"00:55.925 ","End":"01:01.640","Text":"We see here the different forms of sugars found in organisms."},{"Start":"01:01.640 ","End":"01:03.230","Text":"You have the glucose family, amino sugars,"},{"Start":"01:03.230 ","End":"01:06.205","Text":"deoxy sugars, acidic sugars, etc."},{"Start":"01:06.205 ","End":"01:14.120","Text":"One, oxidation of an aldose converts aldehyde group to a carboxylic acid group,"},{"Start":"01:14.120 ","End":"01:20.055","Text":"yielding an aldonic acid such as gluconic acid."},{"Start":"01:20.055 ","End":"01:24.650","Text":"You have oxidation of the aldose,"},{"Start":"01:24.650 ","End":"01:32.510","Text":"and it converts its aldehyde group to a carboxylic acid group and therefore,"},{"Start":"01:32.510 ","End":"01:37.535","Text":"you get an aldonic acid as gluconic acid."},{"Start":"01:37.535 ","End":"01:46.490","Text":"If you have a glucose molecule and you have oxidation of this right here,"},{"Start":"01:46.490 ","End":"01:56.640","Text":"what will happen is an acid will form and the aldonic acid is a result of glucose,"},{"Start":"01:56.640 ","End":"01:59.910","Text":"you have a gluconic acid as an example,"},{"Start":"01:59.910 ","End":"02:04.400","Text":"the aldonic acids are named by appending the suffix on it,"},{"Start":"02:04.400 ","End":"02:06.230","Text":"acid to the roots."},{"Start":"02:06.230 ","End":"02:11.190","Text":"Again, you have glucose and now you\u0027re going to"},{"Start":"02:11.190 ","End":"02:17.070","Text":"add the onic to it and the word acid."},{"Start":"02:17.070 ","End":"02:24.645","Text":"This got oxygenated, and now you have a COOH and OH,"},{"Start":"02:24.645 ","End":"02:26.644","Text":"so oxidation of the carbonyl,"},{"Start":"02:26.644 ","End":"02:31.700","Text":"the aldehyde carbon of glucose to the carboxyl level produces gluconic acid,"},{"Start":"02:31.700 ","End":"02:34.685","Text":"other aldoses yield other aldonic acids."},{"Start":"02:34.685 ","End":"02:40.160","Text":"Oxidation of the carbon at the other end of the carbon chain, C6 of glucose."},{"Start":"02:40.160 ","End":"02:45.770","Text":"Down here, galactose or mannose forms the corresponding uronic acid,"},{"Start":"02:45.770 ","End":"02:50.010","Text":"like glucuronic galacturonic or manauronic acid,"},{"Start":"02:50.010 ","End":"02:56.695","Text":"both aldonic and uronic acids form stable intramolecular esters called lactones."},{"Start":"02:56.695 ","End":"03:01.460","Text":"If we have oxidation of the primary alcohol group of aldoses,"},{"Start":"03:01.460 ","End":"03:06.265","Text":"you can have uronic acids that form."},{"Start":"03:06.265 ","End":"03:10.775","Text":"These are named by appending uronic acid to the root name."},{"Start":"03:10.775 ","End":"03:12.995","Text":"Again you have glucose,"},{"Start":"03:12.995 ","End":"03:15.290","Text":"the root name here."},{"Start":"03:15.290 ","End":"03:18.470","Text":"Now you have glucuronic acid."},{"Start":"03:18.470 ","End":"03:26.800","Text":"Append uronic acid to the root name of the parent aldose and you get deglucuronic acid."},{"Start":"03:26.800 ","End":"03:30.810","Text":"Uronic acids can assume the pyranose,"},{"Start":"03:30.810 ","End":"03:33.495","Text":"furanose, and linear forms."},{"Start":"03:33.495 ","End":"03:34.865","Text":"As you see here,"},{"Start":"03:34.865 ","End":"03:41.750","Text":"it forms this ring and it can have different organizations, the different structures."},{"Start":"03:41.750 ","End":"03:46.535","Text":"Now, the third type of hexose derivative in"},{"Start":"03:46.535 ","End":"03:51.680","Text":"organisms are what happens when you have aldoses and"},{"Start":"03:51.680 ","End":"03:56.195","Text":"ketoses that are reduced under mild conditions"},{"Start":"03:56.195 ","End":"04:01.685","Text":"to yield poly hydroxyl alcohols known as alditols,"},{"Start":"04:01.685 ","End":"04:05.090","Text":"which are named by appending the suffix"},{"Start":"04:05.090 ","End":"04:12.490","Text":"I-T-O-L itol or itol to the root name of the parent aldose."},{"Start":"04:12.490 ","End":"04:15.075","Text":"Xylitol, for example,"},{"Start":"04:15.075 ","End":"04:20.615","Text":"is an alditol used as an alternative sweetener and sugarless gums and candies."},{"Start":"04:20.615 ","End":"04:28.950","Text":"Xylitol, so this is what happens when the carb was reduced and you"},{"Start":"04:28.950 ","End":"04:33.290","Text":"have it now as a polyhydroxyl alcohol and now you"},{"Start":"04:33.290 ","End":"04:38.150","Text":"have a polyhydroxyl alcohol known as an alditol, xylitol."},{"Start":"04:38.150 ","End":"04:42.155","Text":"The fourth derivative is in the case where monosaccharide units"},{"Start":"04:42.155 ","End":"04:46.670","Text":"in which an OH or hydroxyl group is replaced by a hydrogen by H,"},{"Start":"04:46.670 ","End":"04:50.149","Text":"these are known as deoxy sugars."},{"Start":"04:50.149 ","End":"04:56.795","Text":"The most important deoxy sugar biologically is Beta-D-2-deoxyribose,"},{"Start":"04:56.795 ","End":"04:59.540","Text":"which you hopefully remember as being the sugar component"},{"Start":"04:59.540 ","End":"05:03.005","Text":"of DNA\u0027s sugar-phosphate backbone."},{"Start":"05:03.005 ","End":"05:06.215","Text":"We also have this straight-up ribose,"},{"Start":"05:06.215 ","End":"05:09.370","Text":"which is the sugar component of RNA."},{"Start":"05:09.370 ","End":"05:11.690","Text":"Now the substitution of a hydrogen for"},{"Start":"05:11.690 ","End":"05:15.050","Text":"the hydroxyl group at C6 of A galactose or L mannose"},{"Start":"05:15.050 ","End":"05:21.920","Text":"produces L fucose or L nanose respectively."},{"Start":"05:21.920 ","End":"05:25.610","Text":"These deoxy sugars are found in plant polysaccharides and in"},{"Start":"05:25.610 ","End":"05:30.290","Text":"the complex illegal saccharide components of glycoproteins and glycolipids."},{"Start":"05:30.290 ","End":"05:33.845","Text":"The fifth derivative we have of hexoses in organisms"},{"Start":"05:33.845 ","End":"05:38.435","Text":"are the amino sugars and amino sugars formed when the hydroxyl group,"},{"Start":"05:38.435 ","End":"05:41.840","Text":"OH groups are replaced by an amino group."},{"Start":"05:41.840 ","End":"05:46.205","Text":"If one or more hydroxyl is replaced by amino group,"},{"Start":"05:46.205 ","End":"05:50.525","Text":"you have an amino sugar which is often acetylated."},{"Start":"05:50.525 ","End":"05:52.070","Text":"These have different roles."},{"Start":"05:52.070 ","End":"05:55.265","Text":"Some are constituents of glycoproteins and glycolipids."},{"Start":"05:55.265 ","End":"05:58.220","Text":"Some are referred to as sialic acid."},{"Start":"05:58.220 ","End":"06:03.320","Text":"Sialic acid is a term you may have heard because it\u0027s something we find in"},{"Start":"06:03.320 ","End":"06:09.260","Text":"the body and is mentioned as a supplement and whatnot in dietary supplements, etc."},{"Start":"06:09.260 ","End":"06:12.380","Text":"1, 9 carbon acidic sugar deserves mention."},{"Start":"06:12.380 ","End":"06:17.285","Text":"The N-acetylmuramic acid is sialic acid,"},{"Start":"06:17.285 ","End":"06:20.270","Text":"but often referred to simply as sialic acid,"},{"Start":"06:20.270 ","End":"06:26.320","Text":"and it is a component of many glycoproteins and glycolipids in animals."},{"Start":"06:26.320 ","End":"06:32.815","Text":"D-glucosamine and D-galactosamine are the most common amino sugars."},{"Start":"06:32.815 ","End":"06:35.050","Text":"Sure you\u0027ve heard of glucosamine."},{"Start":"06:35.050 ","End":"06:38.390","Text":"That is again, something that people talk about with regard to"},{"Start":"06:38.390 ","End":"06:43.195","Text":"supplements and health in dietary supplements to take for health."},{"Start":"06:43.195 ","End":"06:46.480","Text":"In glucosamine, galactosamine, and mannosamine,"},{"Start":"06:46.480 ","End":"06:50.735","Text":"the hydroxyl at C2 of the parent compound is replaced with an amino group."},{"Start":"06:50.735 ","End":"06:55.720","Text":"The amino group is nearly always condensed with acidic, as in N-acetylglucosamine."},{"Start":"06:55.720 ","End":"06:59.630","Text":"This glucosamine derivative is part of many structural polymers,"},{"Start":"06:59.630 ","End":"07:02.935","Text":"including those of the bacterial cell wall."},{"Start":"07:02.935 ","End":"07:07.280","Text":"With this, we completed talking about the hexose derivatives in organisms."},{"Start":"07:07.280 ","End":"07:09.140","Text":"We mentioned 5 of them."},{"Start":"07:09.140 ","End":"07:10.745","Text":"Let me just remind you."},{"Start":"07:10.745 ","End":"07:12.845","Text":"You have the aldonic acid,"},{"Start":"07:12.845 ","End":"07:17.075","Text":"which is when you have oxidation of an aldose and an aldehyde group,"},{"Start":"07:17.075 ","End":"07:25.590","Text":"and the names of the parent has the onic acid added to the root, so gluconic acid."},{"Start":"07:25.590 ","End":"07:29.944","Text":"You then have oxidation of the primary alcohol group of aldoses,"},{"Start":"07:29.944 ","End":"07:35.180","Text":"and that results in uronic acids when you have the aldose or"},{"Start":"07:35.180 ","End":"07:40.920","Text":"ketose reduced and resulting in a polyhydroxyl alcohol,"},{"Start":"07:40.920 ","End":"07:43.225","Text":"it is termed alditols."},{"Start":"07:43.225 ","End":"07:47.900","Text":"The fourth thing that occurs when an OH group is replaced"},{"Start":"07:47.900 ","End":"07:53.305","Text":"by a hydrogen group in a monosaccharide and that forms the deoxy sugars,"},{"Start":"07:53.305 ","End":"07:56.600","Text":"and you have the amino sugar which is"},{"Start":"07:56.600 ","End":"07:59.690","Text":"formed when the hydroxyl group is replaced by an amino group,"},{"Start":"07:59.690 ","End":"08:01.810","Text":"so these are the 5."},{"Start":"08:01.810 ","End":"08:05.960","Text":"With this, we completed the hexose derivatives in organisms lesson,"},{"Start":"08:05.960 ","End":"08:07.130","Text":"and at this point,"},{"Start":"08:07.130 ","End":"08:11.700","Text":"you should know the 5 various derivatives of simple sugars."}],"ID":30497},{"Watched":false,"Name":"Exercise 16","Duration":"3m 35s","ChapterTopicVideoID":28943,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.965","Text":"Let\u0027s go on to an exercise within hexose derivatives in organisms."},{"Start":"00:04.965 ","End":"00:10.830","Text":"Part 1, in addition to simple hexose such as glucose, galactose, mannose,"},{"Start":"00:10.830 ","End":"00:13.110","Text":"there are a number of sugar derivatives in which"},{"Start":"00:13.110 ","End":"00:16.590","Text":"a hydroxyl group in the parent compound is"},{"Start":"00:16.590 ","End":"00:23.100","Text":"replaced with another substituent or a carbon atom is oxidized to a carboxyl group."},{"Start":"00:23.100 ","End":"00:26.675","Text":"List these. Now we mentioned there are 5 of them."},{"Start":"00:26.675 ","End":"00:30.305","Text":"We have the aldonic acids such as glucuronic acid."},{"Start":"00:30.305 ","End":"00:32.480","Text":"We have uronic acids,"},{"Start":"00:32.480 ","End":"00:34.610","Text":"we have alditols,"},{"Start":"00:34.610 ","End":"00:37.205","Text":"and we mentioned glucuronic acid as well."},{"Start":"00:37.205 ","End":"00:40.708","Text":"We have deoxy sugars,"},{"Start":"00:40.708 ","End":"00:43.599","Text":"and we have amino sugars."},{"Start":"00:43.599 ","End":"00:49.565","Text":"Part 2, elaborate on each one of the sugar derivatives mentioned in Part 1."},{"Start":"00:49.565 ","End":"00:53.210","Text":"We started with the first one which is the aldonic acid."},{"Start":"00:53.210 ","End":"00:57.410","Text":"Oxidation of an aldose converts this aldehyde group to"},{"Start":"00:57.410 ","End":"01:05.400","Text":"a carboxylic acid group yielding an aldonic acid such as glucuronic acid,"},{"Start":"01:05.400 ","End":"01:12.080","Text":"so you thereby from this conversion result in an aldonic acid."},{"Start":"01:12.080 ","End":"01:14.360","Text":"The second group, the uronic acids."},{"Start":"01:14.360 ","End":"01:20.045","Text":"Oxidation of the primary alcohol group of aldoses yields uronic acids"},{"Start":"01:20.045 ","End":"01:25.643","Text":"which are named by appending uronic acid to the root name of a parent aldose."},{"Start":"01:25.643 ","End":"01:34.420","Text":"For example, D-glucose it will be D-gluconoronic acid."},{"Start":"01:34.420 ","End":"01:39.110","Text":"Uronic acids can assume the pyranose, the furanose,"},{"Start":"01:39.110 ","End":"01:43.850","Text":"and the linear forms of the carb."},{"Start":"01:43.850 ","End":"01:47.600","Text":"The third derivative is what happens when you have a case"},{"Start":"01:47.600 ","End":"01:51.170","Text":"of aldoses and ketoses that are reduced,"},{"Start":"01:51.170 ","End":"01:56.765","Text":"and yield a polyhydroxyl alcohol that is known as alditols which are"},{"Start":"01:56.765 ","End":"02:05.240","Text":"named by appending the suffix -itol the root name of the parent aldose or ketose."},{"Start":"02:05.240 ","End":"02:10.085","Text":"The example xylitol was given which"},{"Start":"02:10.085 ","End":"02:16.085","Text":"is an alditol used as an alternative sweetener in sugarless gums and candies."},{"Start":"02:16.085 ","End":"02:22.340","Text":"Then we have monosaccharide units in which an OH group is replaced by H,"},{"Start":"02:22.340 ","End":"02:24.994","Text":"and these are known as deoxy sugars."},{"Start":"02:24.994 ","End":"02:31.915","Text":"Now the most important deoxy sugar biologically is beta-2-D deoxyribose."},{"Start":"02:31.915 ","End":"02:35.765","Text":"Hopefully you remember by this point, this is familiar."},{"Start":"02:35.765 ","End":"02:40.790","Text":"This is the sugar component of DNAs sugar phosphate backbone."},{"Start":"02:40.790 ","End":"02:43.820","Text":"The derivative mentioned was the amino sugar and this is"},{"Start":"02:43.820 ","End":"02:47.045","Text":"what is formed when one or more hydroxyl"},{"Start":"02:47.045 ","End":"02:53.450","Text":"OH groups are replaced by an amino group which is often acetylated."},{"Start":"02:53.450 ","End":"02:55.355","Text":"These have different roles."},{"Start":"02:55.355 ","End":"02:58.400","Text":"Some are constituents of glycoproteins and glycolipids."},{"Start":"02:58.400 ","End":"03:01.370","Text":"Some are referred to as sialic acids and"},{"Start":"03:01.370 ","End":"03:05.120","Text":"the 1-9 carbon acidic sugar that was mentioned in class is"},{"Start":"03:05.120 ","End":"03:07.430","Text":"the N-acetylmuramic acid which is"},{"Start":"03:07.430 ","End":"03:12.075","Text":"a sialic acid and is often referred to simply as sialic acids."},{"Start":"03:12.075 ","End":"03:14.705","Text":"Commonly when someone says sialic acid,"},{"Start":"03:14.705 ","End":"03:21.290","Text":"they actually are referring to this specific sialic acid which is an acetamuramic acid."},{"Start":"03:21.290 ","End":"03:23.660","Text":"This is a component of many glycoproteins,"},{"Start":"03:23.660 ","End":"03:25.460","Text":"and glycolipids and animals."},{"Start":"03:25.460 ","End":"03:32.580","Text":"Now, D-glucosamine and D-galactosamine are the most common amino sugars."}],"ID":30498},{"Watched":false,"Name":"Exercise 17","Duration":"1m 56s","ChapterTopicVideoID":28945,"CourseChapterTopicPlaylistID":293019,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.730","Text":"Let\u0027s dive into another exercise covering the topic of hexose derivatives in organisms."},{"Start":"00:05.730 ","End":"00:09.930","Text":"List at least 2 examples of hexose derivatives found in nature."},{"Start":"00:09.930 ","End":"00:13.020","Text":"1, oxidation of carbonyl aldehyde carbon of"},{"Start":"00:13.020 ","End":"00:16.455","Text":"glucose to the carboxyl level produces gluconic acid;"},{"Start":"00:16.455 ","End":"00:20.625","Text":"other aldoses yield other aldonic acids."},{"Start":"00:20.625 ","End":"00:23.100","Text":"Another case we mentioned oxidation of"},{"Start":"00:23.100 ","End":"00:26.040","Text":"the carbon at the other end of the carbon chain, the C-6."},{"Start":"00:26.040 ","End":"00:29.880","Text":"This happens at the carbonyl aldehyde."},{"Start":"00:29.880 ","End":"00:35.550","Text":"The C-1, when you have oxidation at the other side, the C-6 glucose,"},{"Start":"00:35.550 ","End":"00:39.945","Text":"galactose or mannose, you have the corresponding uronic acid,"},{"Start":"00:39.945 ","End":"00:43.365","Text":"glucuronic, galacturonic, or mannuronic acid."},{"Start":"00:43.365 ","End":"00:45.950","Text":"This is another example of a derivative."},{"Start":"00:45.950 ","End":"00:49.370","Text":"Aldonic acids is 1."},{"Start":"00:49.370 ","End":"00:54.290","Text":"You have uronic acids as 2,"},{"Start":"00:54.290 ","End":"00:58.940","Text":"we also talked about the most important deoxy sugar biologically known,"},{"Start":"00:58.940 ","End":"01:01.340","Text":"which is Beta-D-2-deoxyribose,"},{"Start":"01:01.340 ","End":"01:05.044","Text":"the sugar component of DNA\u0027s sugar phosphate backbone."},{"Start":"01:05.044 ","End":"01:08.920","Text":"This is the deoxy sugars."},{"Start":"01:08.920 ","End":"01:11.510","Text":"The third group, we mentioned,"},{"Start":"01:11.510 ","End":"01:16.070","Text":"the deoxyribose that is part of the DNA,"},{"Start":"01:16.070 ","End":"01:18.650","Text":"the sugar component of the phosphate backbone, very,"},{"Start":"01:18.650 ","End":"01:22.000","Text":"very important hexose derivative."},{"Start":"01:22.000 ","End":"01:26.390","Text":"The fourth 1 mentioned that L-fucose or L-rhamnose are deoxy sugars found in"},{"Start":"01:26.390 ","End":"01:28.040","Text":"plant polysaccharides and in"},{"Start":"01:28.040 ","End":"01:32.030","Text":"complex oligosaccharides components of glycoproteins and glycolipids."},{"Start":"01:32.030 ","End":"01:35.990","Text":"These are important in plants."},{"Start":"01:35.990 ","End":"01:38.360","Text":"We also mentioned D-glucosamine and"},{"Start":"01:38.360 ","End":"01:42.440","Text":"D-galactosamine as being the most common amino sugars."},{"Start":"01:42.440 ","End":"01:46.550","Text":"A glucosamine derivative is part of many structural polymers,"},{"Start":"01:46.550 ","End":"01:49.805","Text":"including those of the bacterial cell wall."},{"Start":"01:49.805 ","End":"01:52.955","Text":"As long as you remember 2 of these examples,"},{"Start":"01:52.955 ","End":"01:56.130","Text":"any of them, you\u0027re golden."}],"ID":30499}],"Thumbnail":null,"ID":293019},{"Name":"Polysaccharides","TopicPlaylistFirstVideoID":0,"Duration":null,"Videos":[{"Watched":false,"Name":"Intro to Polysaccharides","Duration":"6m 11s","ChapterTopicVideoID":28951,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":"https://www.proprep.uk/Images/Videos_Thumbnails/28951.jpeg","UploadDate":"2022-05-19T07:32:40.3500000","DurationForVideoObject":"PT6M11S","Description":null,"MetaTitle":"Intro to Polysaccharides: Video + Workbook | Proprep","MetaDescription":"Carbohydrates - Polysaccharides. Watch the video made by an expert in the field. Download the workbook and maximize your learning.","Canonical":"https://www.proprep.uk/general-modules/all/biochemistry/carbohydrates/polysaccharides/vid30500","VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.545","Text":"Welcome back. We\u0027re in the chapter on carbohydrates."},{"Start":"00:04.545 ","End":"00:06.375","Text":"We covered the simple carbohydrates,"},{"Start":"00:06.375 ","End":"00:10.050","Text":"and now we are going to talk about the polysaccharides."},{"Start":"00:10.050 ","End":"00:13.845","Text":"In this section, we\u0027re going to introduce the polysaccharide,"},{"Start":"00:13.845 ","End":"00:16.680","Text":"and we will learn about the types of polysaccharides"},{"Start":"00:16.680 ","End":"00:20.310","Text":"and the differences between the polysaccharides."},{"Start":"00:20.310 ","End":"00:24.480","Text":"Most carbohydrates found in nature occur as polysaccharides,"},{"Start":"00:24.480 ","End":"00:27.750","Text":"which are polymers of medium to high molecular weight,"},{"Start":"00:27.750 ","End":"00:31.250","Text":"and are also known as glycans."},{"Start":"00:31.250 ","End":"00:37.655","Text":"These generally consist of monosaccharides linked together by glycosidic bonds."},{"Start":"00:37.655 ","End":"00:39.410","Text":"Now, the different polysaccharides,"},{"Start":"00:39.410 ","End":"00:44.735","Text":"different from each other in the identity of the recurring monosaccharide units,"},{"Start":"00:44.735 ","End":"00:47.465","Text":"in the length of their chains,"},{"Start":"00:47.465 ","End":"00:53.165","Text":"in the types of bonds linking the units that are part of the polysaccharide,"},{"Start":"00:53.165 ","End":"00:57.485","Text":"and in the degree of branching of the chain."},{"Start":"00:57.485 ","End":"01:03.000","Text":"This goes back to when we talked about monomers,"},{"Start":"01:03.000 ","End":"01:06.975","Text":"polymers, mono 1,"},{"Start":"01:06.975 ","End":"01:11.220","Text":"poly many, so this means like a unit."},{"Start":"01:11.220 ","End":"01:17.925","Text":"The same idea monosaccharides, polysaccharide."},{"Start":"01:17.925 ","End":"01:24.934","Text":"It just means it\u0027s a monomer of a sugar unit."},{"Start":"01:24.934 ","End":"01:32.490","Text":"Now, they\u0027re classified into either homopolysaccharides or heteropolysaccharides,"},{"Start":"01:32.490 ","End":"01:38.068","Text":"with the first consisting of 1 type of monosaccharide,"},{"Start":"01:38.068 ","End":"01:42.790","Text":"and the ladder consisting of different types of monosaccharides."},{"Start":"01:42.790 ","End":"01:45.710","Text":"We should be familiar with these terms,"},{"Start":"01:45.710 ","End":"01:51.080","Text":"hormo and hetero because we introduce them and in Greek we basically have the same so,"},{"Start":"01:51.080 ","End":"01:54.420","Text":"1 type of monosaccharide,"},{"Start":"01:55.760 ","End":"01:59.430","Text":"and hetero is different,"},{"Start":"01:59.430 ","End":"02:04.575","Text":"various, several different type."},{"Start":"02:04.575 ","End":"02:06.320","Text":"If you see the figure here,"},{"Start":"02:06.320 ","End":"02:10.160","Text":"can you tell me which is a homopolysaccharide and which is a heteropolysaccharide."},{"Start":"02:10.160 ","End":"02:14.285","Text":"Well, here you see a chain of the same repeating unit,"},{"Start":"02:14.285 ","End":"02:17.090","Text":"even though this isn\u0027t linear and this is branched,"},{"Start":"02:17.090 ","End":"02:21.950","Text":"while here you see a chain of different units."},{"Start":"02:21.950 ","End":"02:24.245","Text":"In this case, it\u0027s 2 different units."},{"Start":"02:24.245 ","End":"02:26.435","Text":"Here you see 3 different units,"},{"Start":"02:26.435 ","End":"02:28.420","Text":"and this one is linear and this one is that branch,"},{"Start":"02:28.420 ","End":"02:36.150","Text":"so this would be the hetero and this will be the homopolysaccharide."},{"Start":"02:36.150 ","End":"02:40.595","Text":"This is as designated by the prefix homo,"},{"Start":"02:40.595 ","End":"02:43.474","Text":"same, hetero, different."},{"Start":"02:43.474 ","End":"02:48.980","Text":"In other words, homopolysaccharides contain only a single monomeric species,"},{"Start":"02:48.980 ","End":"02:54.265","Text":"while heteropolysaccharides contain 2 or more different kinds."},{"Start":"02:54.265 ","End":"02:58.080","Text":"Defining these again, hormo and heteropolysaccharides or polysaccharides,"},{"Start":"02:58.080 ","End":"03:00.975","Text":"that may be composed of 1,"},{"Start":"03:00.975 ","End":"03:03.425","Text":"2 or several different monosaccharides"},{"Start":"03:03.425 ","End":"03:05.970","Text":"in straight or branched chains of varying lengths,"},{"Start":"03:05.970 ","End":"03:11.205","Text":"and homo and hetero refers to the variation of the single units."},{"Start":"03:11.205 ","End":"03:13.850","Text":"Some homo polysaccharides serve as"},{"Start":"03:13.850 ","End":"03:18.605","Text":"storage forms of monosaccharides that are used as fuels,"},{"Start":"03:18.605 ","End":"03:23.555","Text":"with starch and glycogen being examples of such homo polysaccharides."},{"Start":"03:23.555 ","End":"03:26.585","Text":"Other homo polysaccharides serve as structural elements"},{"Start":"03:26.585 ","End":"03:29.885","Text":"in plant cell walls and animal exoskeletons,"},{"Start":"03:29.885 ","End":"03:31.565","Text":"with cellulose and chitin,"},{"Start":"03:31.565 ","End":"03:36.673","Text":"or chiton,or chiton being examples of such polysaccharides."},{"Start":"03:36.673 ","End":"03:38.030","Text":"I know the term as chitin,"},{"Start":"03:38.030 ","End":"03:40.865","Text":"but I\u0027ve heard it pronounced differently."},{"Start":"03:40.865 ","End":"03:42.740","Text":"I just want to make sure that we know the term."},{"Start":"03:42.740 ","End":"03:45.050","Text":"We will introduce these later."},{"Start":"03:45.050 ","End":"03:46.505","Text":"But just to say,"},{"Start":"03:46.505 ","End":"03:54.405","Text":"we mentioned starch just now and glycogen as examples of fuels,"},{"Start":"03:54.405 ","End":"04:01.900","Text":"and we mentioned cellulose and chitin as structural."},{"Start":"04:01.900 ","End":"04:07.550","Text":"Heteropolysaccharides provide extracellular support for organisms of all kingdoms."},{"Start":"04:07.550 ","End":"04:12.635","Text":"For example, the rigid layer of the bacterial cell envelope, the peptidoglycan,"},{"Start":"04:12.635 ","End":"04:14.050","Text":"is composed in part of"},{"Start":"04:14.050 ","End":"04:18.415","Text":"a heteropolysaccharide built from 2 alternating monosaccharide units,"},{"Start":"04:18.415 ","End":"04:20.705","Text":"so these are 2 alternative monosaccharide units."},{"Start":"04:20.705 ","End":"04:23.345","Text":"We\u0027re giving an example of"},{"Start":"04:23.345 ","End":"04:29.895","Text":"bacterial cell wall having"},{"Start":"04:29.895 ","End":"04:37.065","Text":"the peptidoglycan and the tido have the hint that it\u0027s a peptide,"},{"Start":"04:37.065 ","End":"04:42.668","Text":"so peptide, protein portion, and glycan sugar."},{"Start":"04:42.668 ","End":"04:48.260","Text":"It is a molecule that\u0027s composed of peptides and sugar units."},{"Start":"04:48.260 ","End":"04:51.680","Text":"Now, for example, in animal tissues,"},{"Start":"04:51.680 ","End":"04:56.480","Text":"the extracellular space occupied by several types of heteropolysaccharides which"},{"Start":"04:56.480 ","End":"05:01.580","Text":"form a matrix that holds individuals cells together and provides protection,"},{"Start":"05:01.580 ","End":"05:05.415","Text":"shape, and support to cells, tissues, and organs."},{"Start":"05:05.415 ","End":"05:07.790","Text":"Now, unlike proteins,"},{"Start":"05:07.790 ","End":"05:12.245","Text":"polysaccharides generally do not have definite molecular weight,"},{"Start":"05:12.245 ","End":"05:16.550","Text":"whereas we know a certain protein it will have a certain kd, a certain molecular weight."},{"Start":"05:16.550 ","End":"05:20.180","Text":"Polysaccharides do not have this definite molecular weight."},{"Start":"05:20.180 ","End":"05:21.830","Text":"This difference, or the consequence of"},{"Start":"05:21.830 ","End":"05:24.404","Text":"the mechanisms of assembly of the 2 types of polymers,"},{"Start":"05:24.404 ","End":"05:26.120","Text":"while proteins are synthesized on"},{"Start":"05:26.120 ","End":"05:30.170","Text":"a template messenger RNA so we have the DNA, the messenger RNA,"},{"Start":"05:30.170 ","End":"05:32.750","Text":"and then you have the ribosome that comes to the messenger RNA and brings"},{"Start":"05:32.750 ","End":"05:35.443","Text":"the tRNAs and takes the amino acids,"},{"Start":"05:35.443 ","End":"05:37.400","Text":"and build the protein."},{"Start":"05:37.400 ","End":"05:42.530","Text":"It\u0027s our defined sequence in length by enzymes that follow the template exactly."},{"Start":"05:42.530 ","End":"05:45.710","Text":"For polysaccharide synthesis, there is no template rather"},{"Start":"05:45.710 ","End":"05:48.870","Text":"the program for polysaccharide synthesis is intrinsic to"},{"Start":"05:48.870 ","End":"05:54.150","Text":"the enzymes that catalyze"},{"Start":"05:54.150 ","End":"05:57.140","Text":"the polymerization of the monomeric units and there is"},{"Start":"05:57.140 ","End":"06:01.115","Text":"no specific stopping point in the synthetic process."},{"Start":"06:01.115 ","End":"06:03.110","Text":"With this, we completed the introduction to"},{"Start":"06:03.110 ","End":"06:06.005","Text":"polysaccharides within the topic of polysaccharides."},{"Start":"06:06.005 ","End":"06:08.480","Text":"We covered the different types of polysaccharides,"},{"Start":"06:08.480 ","End":"06:12.090","Text":"and the differences between the polysaccharides."}],"ID":30500},{"Watched":false,"Name":"Exercise 1","Duration":"1m 13s","ChapterTopicVideoID":28952,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.845","Text":"Welcome to an exercise covering intro to polysaccharides."},{"Start":"00:04.845 ","End":"00:06.825","Text":"What are glycans?"},{"Start":"00:06.825 ","End":"00:10.785","Text":"Most carbohydrates found in nature occur as polysaccharides,"},{"Start":"00:10.785 ","End":"00:16.245","Text":"which are polymers of medium to high molecular weight and are termed glycans."},{"Start":"00:16.245 ","End":"00:22.560","Text":"Glycans is another term or glycan is another term for polysaccharide;"},{"Start":"00:22.560 ","End":"00:26.100","Text":"it is synonymous with polysaccharide."},{"Start":"00:26.100 ","End":"00:29.340","Text":"Then let\u0027s try to think what a polysaccharide is."},{"Start":"00:29.340 ","End":"00:31.455","Text":"Remember, poly is many."},{"Start":"00:31.455 ","End":"00:33.660","Text":"Saccharide comes from the term sugar."},{"Start":"00:33.660 ","End":"00:36.165","Text":"This is all from Greek language."},{"Start":"00:36.165 ","End":"00:41.935","Text":"It is a chain of many units of saccharides of sugar."},{"Start":"00:41.935 ","End":"00:45.349","Text":"Monosaccharides, some cases it can be a dye saccharides."},{"Start":"00:45.349 ","End":"00:48.890","Text":"Basically, if it\u0027s repeating units of 2 monosaccharides,"},{"Start":"00:48.890 ","End":"00:53.210","Text":"you can say it\u0027s repeating units of a disaccharide because it is a monosaccharide A,"},{"Start":"00:53.210 ","End":"00:55.730","Text":"monosaccharide B, glucose,"},{"Start":"00:55.730 ","End":"00:58.295","Text":"fructose if you have repeating units of this."},{"Start":"00:58.295 ","End":"01:01.565","Text":"This is a disaccharide because it\u0027s 2 monosaccharides,"},{"Start":"01:01.565 ","End":"01:05.315","Text":"then you can have a chain of repeating disaccharides and again,"},{"Start":"01:05.315 ","End":"01:07.535","Text":"you will have a polysaccharide."},{"Start":"01:07.535 ","End":"01:13.170","Text":"So glycans are polysaccharides."}],"ID":30501},{"Watched":false,"Name":"Exercise 2","Duration":"1m 31s","ChapterTopicVideoID":28953,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.425","Text":"We have another exercise within the introduction to polysaccharides,"},{"Start":"00:04.425 ","End":"00:09.015","Text":"list at least 3 things that differentiate between various types of glycans."},{"Start":"00:09.015 ","End":"00:12.810","Text":"We mentioned a couple more but try to remember"},{"Start":"00:12.810 ","End":"00:16.560","Text":"3. as I go through these, hopefully, you remembered,"},{"Start":"00:16.560 ","End":"00:23.115","Text":"oh glycans differ from each other in the identity of the recurring monosaccharide units,"},{"Start":"00:23.115 ","End":"00:26.130","Text":"this could be a glucose or something else."},{"Start":"00:26.130 ","End":"00:31.910","Text":"The other thing that differentiates them is the length of their chains,"},{"Start":"00:31.910 ","End":"00:35.260","Text":"meaning how many units there are."},{"Start":"00:35.260 ","End":"00:43.685","Text":"Specific polysaccharides will have a certain range of number of units that defines them."},{"Start":"00:43.685 ","End":"00:46.670","Text":"Another thing that differentiates between"},{"Start":"00:46.670 ","End":"00:51.410","Text":"polysaccharides is the types of bonds linking the units."},{"Start":"00:51.410 ","End":"00:55.100","Text":"If you have a little bit of different bonds between the different units it"},{"Start":"00:55.100 ","End":"00:59.490","Text":"will change the characteristic and the polysaccharide."},{"Start":"00:59.490 ","End":"01:03.230","Text":"The fourth thing we mentioned is the degree of branching."},{"Start":"01:03.230 ","End":"01:09.940","Text":"We said it can be either linear or branched."},{"Start":"01:09.940 ","End":"01:13.610","Text":"Polysaccharide chains can be linear or branched and within the"},{"Start":"01:13.610 ","End":"01:17.330","Text":"branched it could vary in the amount of branching."},{"Start":"01:17.330 ","End":"01:19.865","Text":"We will show examples of these in"},{"Start":"01:19.865 ","End":"01:23.825","Text":"later lessons when we actually talk about specific polysaccharides."},{"Start":"01:23.825 ","End":"01:26.375","Text":"Hopefully you remembered at least 3 of them"},{"Start":"01:26.375 ","End":"01:30.870","Text":"and if you\u0027re a rockstar you remembered all 4."}],"ID":30502},{"Watched":false,"Name":"Exercise 3","Duration":"2m 2s","ChapterTopicVideoID":28954,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:07.305","Text":"We\u0027re back within the section of intro to polysaccharides with another exercise."},{"Start":"00:07.305 ","End":"00:11.280","Text":"Name and define what glycans are classified into."},{"Start":"00:11.280 ","End":"00:14.235","Text":"Remember glycans are polysaccharides."},{"Start":"00:14.235 ","End":"00:16.905","Text":"This is a synonymous term for polysaccharides."},{"Start":"00:16.905 ","End":"00:21.105","Text":"What are the classifications that we mentioned in the lesson?"},{"Start":"00:21.105 ","End":"00:29.340","Text":"Well, glycans are classified into either homopolysaccharides or heteropolysaccharides."},{"Start":"00:29.440 ","End":"00:32.690","Text":"We have these familiar terms again,"},{"Start":"00:32.690 ","End":"00:35.420","Text":"homo, and hetero, and then polysaccharides."},{"Start":"00:35.420 ","End":"00:37.730","Text":"The more we go over similar terms that are"},{"Start":"00:37.730 ","End":"00:40.775","Text":"used over and over in biology and biochemistry,"},{"Start":"00:40.775 ","End":"00:43.645","Text":"it should sit as more familiar."},{"Start":"00:43.645 ","End":"00:45.975","Text":"Thus, we can define"},{"Start":"00:45.975 ","End":"00:51.620","Text":"the homopolysaccharides as being those that consist of 1 type of monosaccharides"},{"Start":"00:51.620 ","End":"00:55.860","Text":"because homo means same and the ladder"},{"Start":"00:55.860 ","End":"01:03.545","Text":"heteropolysaccharides consist of different types of monosaccharides units."},{"Start":"01:03.545 ","End":"01:06.740","Text":"Again, as designated by the prefix homo,"},{"Start":"01:06.740 ","End":"01:09.485","Text":"same versus hetero, different."},{"Start":"01:09.485 ","End":"01:15.154","Text":"In other words, homopolysaccharides contain only a single monomeric species,"},{"Start":"01:15.154 ","End":"01:17.525","Text":"even if it\u0027s linear or branched."},{"Start":"01:17.525 ","End":"01:20.540","Text":"1 monomeric species that\u0027s repeating,"},{"Start":"01:20.540 ","End":"01:22.550","Text":"it\u0027s signified here by the yellow."},{"Start":"01:22.550 ","End":"01:24.110","Text":"They have the same structure,"},{"Start":"01:24.110 ","End":"01:26.030","Text":"the same color. They\u0027re the same."},{"Start":"01:26.030 ","End":"01:30.380","Text":"While heteropolysaccharides contain 2 or more different kinds here,"},{"Start":"01:30.380 ","End":"01:31.790","Text":"for example, you have blue and pink,"},{"Start":"01:31.790 ","End":"01:37.480","Text":"so this distinguishes it as 2 different monosaccharide units."},{"Start":"01:37.480 ","End":"01:39.000","Text":"Here you have 3, you have green, blue,"},{"Start":"01:39.000 ","End":"01:40.925","Text":"and pink so these are 3 different."},{"Start":"01:40.925 ","End":"01:43.205","Text":"You have linear and branched again."},{"Start":"01:43.205 ","End":"01:49.210","Text":"Homopolysaccharides and heteropolysaccharides can be either linear or branched."},{"Start":"01:49.210 ","End":"01:53.359","Text":"The difference is the monosaccharide units,"},{"Start":"01:53.359 ","End":"01:55.910","Text":"the individual units that make up the chain."},{"Start":"01:55.910 ","End":"01:59.335","Text":"Homo, the same, hetero different."},{"Start":"01:59.335 ","End":"02:03.220","Text":"With that we completed this exercise."}],"ID":30503},{"Watched":false,"Name":"Homopolysaccharides Part 1","Duration":"10m 39s","ChapterTopicVideoID":28960,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:03.180","Text":"Now that we\u0027re familiar with the term polysaccharides,"},{"Start":"00:03.180 ","End":"00:06.510","Text":"we are going to talk about polysaccharides for"},{"Start":"00:06.510 ","End":"00:10.620","Text":"fuel and specifically, homopolysaccharides."},{"Start":"00:10.620 ","End":"00:12.750","Text":"In this section, we will learn about types of"},{"Start":"00:12.750 ","End":"00:18.000","Text":"energy storage polysaccharides and the characteristics of such polysaccharides."},{"Start":"00:18.000 ","End":"00:20.600","Text":"We\u0027re going to split this section into a couple of"},{"Start":"00:20.600 ","End":"00:23.720","Text":"parts and we will start with part 1 where we will"},{"Start":"00:23.720 ","End":"00:29.645","Text":"focus on the energy storage polysaccharide starch and the characteristics of starch."},{"Start":"00:29.645 ","End":"00:32.825","Text":"Some homopolysaccharides are stored forms of fuel."},{"Start":"00:32.825 ","End":"00:37.070","Text":"Now remember, we have homopolysaccharides and heteropolysaccharides."},{"Start":"00:37.070 ","End":"00:41.235","Text":"Homo means same; hetero means different."},{"Start":"00:41.235 ","End":"00:42.710","Text":"If we have homo polysaccharides,"},{"Start":"00:42.710 ","End":"00:45.020","Text":"they\u0027re made of the same building blocks,"},{"Start":"00:45.020 ","End":"00:51.980","Text":"the same monomer that repeats into a polymer into multiple chain of monomers,"},{"Start":"00:51.980 ","End":"00:56.060","Text":"to a multiple sequence of individual units."},{"Start":"00:56.060 ","End":"00:58.940","Text":"Homopolysaccharide, that is linear versus branched,"},{"Start":"00:58.940 ","End":"01:00.905","Text":"and we have the same with hetero polysaccharides."},{"Start":"01:00.905 ","End":"01:07.580","Text":"In this section, we are talking about the homo polysaccharides that are used as fuel."},{"Start":"01:07.580 ","End":"01:11.480","Text":"The most important storage polysaccharides are"},{"Start":"01:11.480 ","End":"01:15.635","Text":"starch in plant cells and glycogen in animal cells."},{"Start":"01:15.635 ","End":"01:20.150","Text":"These glucose homopolymers in plants and animals serve as"},{"Start":"01:20.150 ","End":"01:24.380","Text":"short-term energy reserves to supplement stored lipids,"},{"Start":"01:24.380 ","End":"01:27.455","Text":"which provide a higher energy yield per gram,"},{"Start":"01:27.455 ","End":"01:30.015","Text":"which we also learn about."},{"Start":"01:30.015 ","End":"01:34.325","Text":"We have starch as the energy storage in plant"},{"Start":"01:34.325 ","End":"01:38.510","Text":"and glycogen as the energy storage in animal."},{"Start":"01:38.510 ","End":"01:41.885","Text":"They are both homopolymers of glucose."},{"Start":"01:41.885 ","End":"01:44.510","Text":"Meaning this individual unit,"},{"Start":"01:44.510 ","End":"01:45.815","Text":"each one of these,"},{"Start":"01:45.815 ","End":"01:48.725","Text":"is a glucose molecule."},{"Start":"01:48.725 ","End":"01:54.280","Text":"Both polysaccharides occur intracellularly as large clusters or granules."},{"Start":"01:54.280 ","End":"01:57.350","Text":"They are found within the cell,"},{"Start":"01:57.350 ","End":"02:01.055","Text":"either of the plant or within the cell of the animal,"},{"Start":"02:01.055 ","End":"02:04.640","Text":"and they are in clusters or granules."},{"Start":"02:04.640 ","End":"02:09.590","Text":"The 2 most abundant forms of glucose polymers are starch and glycogen."},{"Start":"02:09.590 ","End":"02:16.055","Text":"In general, these are the most common forms of glucose as"},{"Start":"02:16.055 ","End":"02:19.190","Text":"a polymer which plants use to store"},{"Start":"02:19.190 ","End":"02:23.060","Text":"the glucose generated by photosynthesis during daylight hours."},{"Start":"02:23.060 ","End":"02:26.480","Text":"Starch is what plants use to store"},{"Start":"02:26.480 ","End":"02:30.335","Text":"the glucose generated by photosynthesis during daylight hours,"},{"Start":"02:30.335 ","End":"02:33.530","Text":"and glycogen, which many types of animals use to"},{"Start":"02:33.530 ","End":"02:37.175","Text":"store dietary sources of glucose, what they consume."},{"Start":"02:37.175 ","End":"02:40.490","Text":"Starch and glycogen molecules are heavily"},{"Start":"02:40.490 ","End":"02:44.270","Text":"hydrated because they have many exposed hydroxyl groups."},{"Start":"02:44.270 ","End":"02:46.010","Text":"Remember, hydroxyl groups,"},{"Start":"02:46.010 ","End":"02:52.325","Text":"OH-, available to hydrogen bond with water."},{"Start":"02:52.325 ","End":"02:54.470","Text":"OH, the hydroxyl groups,"},{"Start":"02:54.470 ","End":"02:58.700","Text":"these can bond with water,"},{"Start":"02:58.700 ","End":"03:02.420","Text":"have hydrogen bonding and associate, and therefore,"},{"Start":"03:02.420 ","End":"03:04.250","Text":"they are considered hydrated,"},{"Start":"03:04.250 ","End":"03:07.865","Text":"meaning they have water molecules associated with them."},{"Start":"03:07.865 ","End":"03:12.035","Text":"They contain branched or linear glucose polymers"},{"Start":"03:12.035 ","End":"03:16.190","Text":"with Alpha-1,4 and Alpha-1,6 glycosidic bonds."},{"Start":"03:16.190 ","End":"03:19.865","Text":"This refers Alpha to the type of bond."},{"Start":"03:19.865 ","End":"03:21.380","Text":"There\u0027s also beta bonds."},{"Start":"03:21.380 ","End":"03:24.515","Text":"We will talk about these in a different context."},{"Start":"03:24.515 ","End":"03:28.905","Text":"1,4, 1,6 refers to the carbon."},{"Start":"03:28.905 ","End":"03:31.100","Text":"Carbon 1,2,3,4,5."},{"Start":"03:31.100 ","End":"03:32.720","Text":"Remember we talked in carbs,"},{"Start":"03:32.720 ","End":"03:34.795","Text":"the carbons are numbered."},{"Start":"03:34.795 ","End":"03:41.265","Text":"It means the link is between carbon-1 of 1 molecule and carbon-4 of the other,"},{"Start":"03:41.265 ","End":"03:42.960","Text":"or 1 and 6,"},{"Start":"03:42.960 ","End":"03:47.175","Text":"1 carbon of 1 molecule and 6 of the other."},{"Start":"03:47.175 ","End":"03:50.960","Text":"What we see here in the figure is for starch,"},{"Start":"03:50.960 ","End":"03:56.744","Text":"we have 2 types of polymers and we have the amylose and amylopectin."},{"Start":"03:56.744 ","End":"03:59.720","Text":"The amylose is linear, non-branch,"},{"Start":"03:59.720 ","End":"04:02.900","Text":"while the amylopectin is a branched chain,"},{"Start":"04:02.900 ","End":"04:06.685","Text":"and glycogen is a branched chain as well."},{"Start":"04:06.685 ","End":"04:12.950","Text":"We see here either the branched or linear glucose polymers."},{"Start":"04:12.950 ","End":"04:15.320","Text":"Well, if you see cellulose,"},{"Start":"04:15.320 ","End":"04:19.015","Text":"this is a different polysaccharide."},{"Start":"04:19.015 ","End":"04:21.425","Text":"It is also a homopolysaccharide."},{"Start":"04:21.425 ","End":"04:23.330","Text":"It is found in plants as well."},{"Start":"04:23.330 ","End":"04:28.880","Text":"You see that cellulose is compact in linear while starch is branched,"},{"Start":"04:28.880 ","End":"04:30.725","Text":"you see here a branched polymer,"},{"Start":"04:30.725 ","End":"04:33.635","Text":"and glycogen is highly branched,"},{"Start":"04:33.635 ","End":"04:38.480","Text":"so this has more branches than the starch."},{"Start":"04:38.480 ","End":"04:41.725","Text":"Glycogen is more highly branched than amylopectin."},{"Start":"04:41.725 ","End":"04:44.075","Text":"Let\u0027s expand on these."},{"Start":"04:44.075 ","End":"04:49.445","Text":"Starch is a mixture of glycans that plants synthesize as their principal energy reserve."},{"Start":"04:49.445 ","End":"04:52.774","Text":"Most plant cells have the ability to form starch,"},{"Start":"04:52.774 ","End":"04:55.670","Text":"which is especially abundant in tubers,"},{"Start":"04:55.670 ","End":"04:59.375","Text":"which are underground stems such as potatoes and in seeds."},{"Start":"04:59.375 ","End":"05:04.820","Text":"It contains 2 types of glucose polymer, amylose and amylopectin."},{"Start":"05:04.820 ","End":"05:07.440","Text":"Amylose, which you see here,"},{"Start":"05:07.440 ","End":"05:09.045","Text":"you see amylose,"},{"Start":"05:09.045 ","End":"05:11.325","Text":"and you see amylopectin,"},{"Start":"05:11.325 ","End":"05:14.220","Text":"which is more branched."},{"Start":"05:14.220 ","End":"05:19.310","Text":"Amylose and amylopectin, the polysaccharides of starch."},{"Start":"05:19.310 ","End":"05:20.975","Text":"Let\u0027s talk about amylose first."},{"Start":"05:20.975 ","End":"05:23.870","Text":"It is a linear polymer that consists of"},{"Start":"05:23.870 ","End":"05:29.525","Text":"long unbranched chains of D-glucose residues connected by Alpha-1,4 linkages."},{"Start":"05:29.525 ","End":"05:31.055","Text":"What we see here is amylose."},{"Start":"05:31.055 ","End":"05:35.040","Text":"What we see here, this is amylose."},{"Start":"05:35.040 ","End":"05:39.965","Text":"It\u0027s a linear change and it has a 1-4 linkage."},{"Start":"05:39.965 ","End":"05:45.304","Text":"Alpha is the type and 1-4, carbon-1 and carbon-4."},{"Start":"05:45.304 ","End":"05:46.640","Text":"Because if we count the carbons,"},{"Start":"05:46.640 ","End":"05:51.670","Text":"this is carbon 1, 2, 3, 4, 5, 6."},{"Start":"05:51.670 ","End":"05:56.775","Text":"So we have carbon-1 and carbon-4 of each 2 molecules;"},{"Start":"05:56.775 ","End":"06:00.690","Text":"1 and 4, 1 and 4, 1 and 4."},{"Start":"06:00.690 ","End":"06:08.060","Text":"Such maltose is an example of an amylose and we introduced maltose in a previous lesson."},{"Start":"06:08.060 ","End":"06:11.830","Text":"It is made of several thousand glucose residues."},{"Start":"06:11.830 ","End":"06:17.825","Text":"Such chains vary molecular weight from a few thousand to more than a million."},{"Start":"06:17.825 ","End":"06:19.985","Text":"That is a huge range,"},{"Start":"06:19.985 ","End":"06:22.610","Text":"a huge spectrum of size."},{"Start":"06:22.610 ","End":"06:24.680","Text":"Amylopectin, on the other hand,"},{"Start":"06:24.680 ","End":"06:31.640","Text":"is a highly branched molecule with Alpha-1,4 glycosidic linkages joining"},{"Start":"06:31.640 ","End":"06:35.330","Text":"successive glucose residues in amylopectin chains with"},{"Start":"06:35.330 ","End":"06:41.030","Text":"the branch points occurring every 24 to 30 residues that are Alpha-1,6 linkages."},{"Start":"06:41.030 ","End":"06:48.405","Text":"The Alpha-1,6 linkages means that it is binding between the carbon-1 and carbon- 6."},{"Start":"06:48.405 ","End":"06:50.595","Text":"We said 1, 2, 3, 4, 5, 6,"},{"Start":"06:50.595 ","End":"06:56.670","Text":"so it would bind this one with the next molecule of one,"},{"Start":"06:56.670 ","End":"06:58.180","Text":"and that is what we see here,"},{"Start":"06:58.180 ","End":"07:00.490","Text":"that is what forms the branches."},{"Start":"07:00.490 ","End":"07:06.030","Text":"It is a linear chain with Alpha-1,4 glycosidic linkages,"},{"Start":"07:06.030 ","End":"07:09.190","Text":"and in addition, the branch that occurs is"},{"Start":"07:09.190 ","End":"07:13.015","Text":"when an additional glucose molecule can come here."},{"Start":"07:13.015 ","End":"07:15.895","Text":"You have additional glucose molecule comes here,"},{"Start":"07:15.895 ","End":"07:18.100","Text":"and the carbon-1,"},{"Start":"07:18.100 ","End":"07:19.945","Text":"this is the carbon- 1,"},{"Start":"07:19.945 ","End":"07:23.370","Text":"will associate with the carbon-6,"},{"Start":"07:23.370 ","End":"07:25.665","Text":"and that\u0027s how this branch forms."},{"Start":"07:25.665 ","End":"07:28.470","Text":"What you see here is the branch forming."},{"Start":"07:28.470 ","End":"07:30.360","Text":"You have the main chain,"},{"Start":"07:30.360 ","End":"07:32.115","Text":"there\u0027s Alpha- 1,4 linkage."},{"Start":"07:32.115 ","End":"07:34.680","Text":"This is the 1, this is 1 and 4,"},{"Start":"07:34.680 ","End":"07:37.805","Text":"so we have here this chain,"},{"Start":"07:37.805 ","End":"07:41.140","Text":"basically is right here and right here."},{"Start":"07:41.140 ","End":"07:46.965","Text":"Then you have a branch that goes up from these."},{"Start":"07:46.965 ","End":"07:49.430","Text":"Up from the 6 carbon,"},{"Start":"07:49.430 ","End":"07:51.410","Text":"there\u0027ll be another glucose here."},{"Start":"07:51.410 ","End":"07:57.424","Text":"This is basically how the amylopectin is structured."},{"Start":"07:57.424 ","End":"08:03.335","Text":"Now amylopectin also has a high molecular weight up to 200 million,"},{"Start":"08:03.335 ","End":"08:07.310","Text":"making these some of the largest molecules in nature."},{"Start":"08:07.310 ","End":"08:11.210","Text":"Again, we\u0027re talking about starch and we have amylose and amylopectin."},{"Start":"08:11.210 ","End":"08:16.700","Text":"What basically gives amylopectin the larger molecular weight,"},{"Start":"08:16.700 ","End":"08:20.284","Text":"up to 200 million versus a million,"},{"Start":"08:20.284 ","End":"08:22.430","Text":"is the fact that it has these branches."},{"Start":"08:22.430 ","End":"08:26.585","Text":"Because the minute you take this chain and start adding branches to it,"},{"Start":"08:26.585 ","End":"08:29.900","Text":"it makes it bigger and more significant."},{"Start":"08:29.900 ","End":"08:36.260","Text":"Again, branching points occur about every 24-30 residues."},{"Start":"08:36.260 ","End":"08:38.206","Text":"If you count 1, 2,"},{"Start":"08:38.206 ","End":"08:40.420","Text":"3, 4, 24,"},{"Start":"08:40.420 ","End":"08:42.490","Text":"there\u0027ll be a branch; 1, 2,3, 4,"},{"Start":"08:42.490 ","End":"08:44.705","Text":"25, there\u0027ll be another branch;"},{"Start":"08:44.705 ","End":"08:46.505","Text":"30, there\u0027ll be another branch."},{"Start":"08:46.505 ","End":"08:48.650","Text":"Going back to this figure here,"},{"Start":"08:48.650 ","End":"08:51.440","Text":"what you see here is the short segment of amylose,"},{"Start":"08:51.440 ","End":"08:57.470","Text":"a linear polymer of D-glucose residues in that Alpha 1-4 linkage as mentioned."},{"Start":"08:57.470 ","End":"09:00.960","Text":"A single chain can contain several thousands of glucose residues,"},{"Start":"09:00.960 ","End":"09:03.005","Text":"so this is just a portion."},{"Start":"09:03.005 ","End":"09:06.080","Text":"Then you have amylopectin has stretches of"},{"Start":"09:06.080 ","End":"09:12.200","Text":"similarly linked residues like this between the branched points."},{"Start":"09:12.200 ","End":"09:19.550","Text":"The branched points occur on this chain when there would be 24 of these."},{"Start":"09:19.550 ","End":"09:20.964","Text":"If you have 1, 2, 3,"},{"Start":"09:20.964 ","End":"09:22.190","Text":"4 times 6,"},{"Start":"09:22.190 ","End":"09:25.540","Text":"there can be a branch like this that will occur."},{"Start":"09:25.540 ","End":"09:31.755","Text":"These branches again are Alpha-1,6 glycosidic bond branch points of amylopectin."},{"Start":"09:31.755 ","End":"09:35.270","Text":"What you see here is a cluster of amylose and"},{"Start":"09:35.270 ","End":"09:40.365","Text":"amylopectin like that believed to occur in starch granules."},{"Start":"09:40.365 ","End":"09:42.860","Text":"Strands of amylopectin, which is in red,"},{"Start":"09:42.860 ","End":"09:49.495","Text":"form double helical structures with each other or with amylose strands in blue."},{"Start":"09:49.495 ","End":"09:53.855","Text":"Glucose residues at the non-reducing ends of the outer branches"},{"Start":"09:53.855 ","End":"09:58.340","Text":"are removed enzymatically during the mobilization of starch for energy production."},{"Start":"09:58.340 ","End":"10:02.495","Text":"Enzymes come in and attack here on the non-reducing ends and can break apart"},{"Start":"10:02.495 ","End":"10:07.200","Text":"each molecule at a time of the chain for the use for fuel."},{"Start":"10:07.200 ","End":"10:11.750","Text":"Glycogen has a similar structure but is more highly branched and more"},{"Start":"10:11.750 ","End":"10:16.920","Text":"compact than the amylopectin branched structure."},{"Start":"10:16.920 ","End":"10:23.690","Text":"Glycogen would be similar to this but have additional branched points."},{"Start":"10:23.690 ","End":"10:30.770","Text":"With that, we completed part 1 of homopolysaccharides for fuel within the section on"},{"Start":"10:30.770 ","End":"10:33.620","Text":"polysaccharides and we talked about"},{"Start":"10:33.620 ","End":"10:39.060","Text":"the energy storage polysaccharides starch and the characteristics of starch."}],"ID":30504},{"Watched":false,"Name":"Homopolysaccharides Part 2","Duration":"7m 56s","ChapterTopicVideoID":28961,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.245","Text":"Welcome back to homopolysaccharides for fuel part 2."},{"Start":"00:04.245 ","End":"00:07.125","Text":"In this section, we will specifically talk about"},{"Start":"00:07.125 ","End":"00:12.420","Text":"the energy storage polysaccharide glycogen and the characteristics of glycogen."},{"Start":"00:12.420 ","End":"00:16.515","Text":"Keep in mind we talked about starch in the previous section to try to"},{"Start":"00:16.515 ","End":"00:21.375","Text":"associate and create parallels and differences between the 2."},{"Start":"00:21.375 ","End":"00:23.549","Text":"Lets go into glycogen."},{"Start":"00:23.549 ","End":"00:26.235","Text":"This one seems to have more branches."},{"Start":"00:26.235 ","End":"00:30.360","Text":"Glycogen is the main storage polysaccharide of animal cells."},{"Start":"00:30.360 ","End":"00:34.260","Text":"The primary structure of glycogen is similar to amylopectin."},{"Start":"00:34.260 ","End":"00:36.030","Text":"It is more highly branched."},{"Start":"00:36.030 ","End":"00:38.130","Text":"Glycogen is a polymer of Alpha-1,"},{"Start":"00:38.130 ","End":"00:41.160","Text":"4-linked subunits similar to the starch chains,"},{"Start":"00:41.160 ","End":"00:42.240","Text":"so it\u0027s Alpha-1,"},{"Start":"00:42.240 ","End":"00:45.960","Text":"4-linked subunits of glucose with Alpha-1,"},{"Start":"00:45.960 ","End":"00:49.370","Text":"6-linked branches, similar to amylopectin,"},{"Start":"00:49.370 ","End":"00:52.520","Text":"but glycogen is more extensively branched."},{"Start":"00:52.520 ","End":"01:00.075","Text":"On average, there\u0027s a branch every 8-12 residues versus,"},{"Start":"01:00.075 ","End":"01:06.705","Text":"do you remember what we said there is in amylopectin and starch, we said 24-30."},{"Start":"01:06.705 ","End":"01:13.600","Text":"This is more highly branched and more compact than starch."},{"Start":"01:13.910 ","End":"01:19.305","Text":"What we\u0027re seeing here is the amylopectin form of starch and glycogen."},{"Start":"01:19.305 ","End":"01:20.720","Text":"To illustrate that,"},{"Start":"01:20.720 ","End":"01:27.560","Text":"this has more branches in the same area because it\u0027s within 8-12 residues."},{"Start":"01:27.560 ","End":"01:32.450","Text":"There could be a branch point versus 24-30 in amylopectin so it is"},{"Start":"01:32.450 ","End":"01:38.621","Text":"more branched and highly compacted and can get up to 200 million versus a million,"},{"Start":"01:38.621 ","End":"01:44.790","Text":"and therefore, it is a very efficient highly packed energy unit."},{"Start":"01:44.790 ","End":"01:47.005","Text":"One analogy is Koosh balls."},{"Start":"01:47.005 ","End":"01:53.660","Text":"Amylopectin and glycogen are like Koosh balls in which the number of fingers,"},{"Start":"01:53.660 ","End":"01:56.150","Text":"which are the non-reducing ends,"},{"Start":"01:56.150 ","End":"02:02.310","Text":"is greater in glycogen than it is in amylopectin."},{"Start":"02:02.450 ","End":"02:04.530","Text":"If we look here,"},{"Start":"02:04.530 ","End":"02:07.610","Text":"we have the Koosh balls and we have the illustration in"},{"Start":"02:07.610 ","End":"02:12.465","Text":"a different way of the amylopectin and glycogen."},{"Start":"02:12.465 ","End":"02:15.950","Text":"We have amylopectin right here with the branch point about once"},{"Start":"02:15.950 ","End":"02:19.595","Text":"every 15-30 glucose residues written here,"},{"Start":"02:19.595 ","End":"02:21.875","Text":"we tend to mentioned 24-30."},{"Start":"02:21.875 ","End":"02:24.100","Text":"Generally, it\u0027s a larger range."},{"Start":"02:24.100 ","End":"02:27.170","Text":"It is more common to be more between 24-30,"},{"Start":"02:27.170 ","End":"02:29.660","Text":"but can occur between 15-30 glucose residues,"},{"Start":"02:29.660 ","End":"02:33.050","Text":"and here we see it\u0027s between 8-12 glucose residues."},{"Start":"02:33.050 ","End":"02:35.750","Text":"This is the glycogen particle."},{"Start":"02:35.750 ","End":"02:37.990","Text":"So you see it\u0027s like this flower."},{"Start":"02:37.990 ","End":"02:42.570","Text":"In the center, you have the reducing end right here,"},{"Start":"02:42.570 ","End":"02:45.965","Text":"and then you have the glucose units,"},{"Start":"02:45.965 ","End":"02:48.860","Text":"which are these ellipses instead of the polygons."},{"Start":"02:48.860 ","End":"02:50.840","Text":"You have the non-reducing end."},{"Start":"02:50.840 ","End":"02:56.150","Text":"See, every branch ends with a non-reducing end,"},{"Start":"02:56.150 ","End":"02:58.040","Text":"and where there\u0027s a branch point,"},{"Start":"02:58.040 ","End":"02:59.320","Text":"there\u0027s also a non-reducing end,"},{"Start":"02:59.320 ","End":"03:00.860","Text":"and then you have the glucose units."},{"Start":"03:00.860 ","End":"03:04.910","Text":"You see here the reducing end,"},{"Start":"03:04.910 ","End":"03:08.820","Text":"the center, and then you see the non-reducing on the outside."},{"Start":"03:08.820 ","End":"03:13.745","Text":"The glycogen is present in all cells yet is especially abundant in the liver,"},{"Start":"03:13.745 ","End":"03:17.090","Text":"where it may constitute as much as 7 percent of the wet weight,"},{"Start":"03:17.090 ","End":"03:18.965","Text":"and in skeletal muscle,"},{"Start":"03:18.965 ","End":"03:22.354","Text":"where it occurs as cytoplasmic granules."},{"Start":"03:22.354 ","End":"03:26.614","Text":"Now in hepatocytes, which are liver cells,"},{"Start":"03:26.614 ","End":"03:30.095","Text":"glycogen is found in large granules,"},{"Start":"03:30.095 ","End":"03:34.070","Text":"which are themselves clusters of small granules composed of single,"},{"Start":"03:34.070 ","End":"03:38.995","Text":"highly branched glycogen molecules with an average molecular weight of several million."},{"Start":"03:38.995 ","End":"03:40.670","Text":"You have the very,"},{"Start":"03:40.670 ","End":"03:44.645","Text":"very branched Koosh balls representing the glycogen."},{"Start":"03:44.645 ","End":"03:48.590","Text":"Such glycogen granules also contain in"},{"Start":"03:48.590 ","End":"03:55.385","Text":"tightly bound form the enzymes responsible for the synthesis and degradation of glycogen."},{"Start":"03:55.385 ","End":"04:00.650","Text":"So they carry them with the molecule itself so that these enzymes can"},{"Start":"04:00.650 ","End":"04:06.380","Text":"break it down for energy or build it up when there is energy provided."},{"Start":"04:06.380 ","End":"04:11.210","Text":"Because each branch and glycogen ends with a non-reducing sugar unit,"},{"Start":"04:11.210 ","End":"04:16.580","Text":"so glycogen molecule has as many non-reducing ends as it has branches,"},{"Start":"04:16.580 ","End":"04:20.665","Text":"but only 1 reducing end."},{"Start":"04:20.665 ","End":"04:23.900","Text":"As we can see here,"},{"Start":"04:23.900 ","End":"04:26.930","Text":"there\u0027s the many non-reducing ends,"},{"Start":"04:26.930 ","End":"04:33.710","Text":"but 1 reducing end and it\u0027s a dimer of glycogenin core protein."},{"Start":"04:33.710 ","End":"04:40.249","Text":"Due to this, when glycogen is used as an energy source,"},{"Start":"04:40.249 ","End":"04:45.755","Text":"glucose units are removed 1 at a time from the non-reducing ends and"},{"Start":"04:45.755 ","End":"04:49.760","Text":"these decorative enzymes that act only at the non-reducing ends"},{"Start":"04:49.760 ","End":"04:53.945","Text":"can work simultaneously on the many branches,"},{"Start":"04:53.945 ","End":"04:57.605","Text":"speeding the conversion of the polymer to monosaccharides."},{"Start":"04:57.605 ","End":"05:01.115","Text":"Because of this many non-reducing ends, in other words,"},{"Start":"05:01.115 ","End":"05:03.214","Text":"glycogen\u0027s highly branched structure,"},{"Start":"05:03.214 ","End":"05:05.090","Text":"which has these many non-reducing ends,"},{"Start":"05:05.090 ","End":"05:07.520","Text":"permits the rapid utilization of glucose in"},{"Start":"05:07.520 ","End":"05:10.460","Text":"time of metabolic need because the enzyme can come and you can"},{"Start":"05:10.460 ","End":"05:15.260","Text":"have multiple enzymes attacking every 1 of"},{"Start":"05:15.260 ","End":"05:22.415","Text":"these blue molecules and making that glucose unit available."},{"Start":"05:22.415 ","End":"05:29.390","Text":"It allows for energy to become available very rapidly in parallel."},{"Start":"05:29.390 ","End":"05:31.475","Text":"Let\u0027s clarify this further."},{"Start":"05:31.475 ","End":"05:35.480","Text":"Because glucose units can be added or removed"},{"Start":"05:35.480 ","End":"05:39.763","Text":"from the non-reducing ends of amylopectin and glycogen,"},{"Start":"05:39.763 ","End":"05:41.615","Text":"the more branch points they have,"},{"Start":"05:41.615 ","End":"05:45.905","Text":"the more ends there are available for the glucose retrieval and storage,"},{"Start":"05:45.905 ","End":"05:52.285","Text":"making glycogen a more efficient storage form of glucose than amylopectin."},{"Start":"05:52.285 ","End":"05:54.750","Text":"Again, if we\u0027re comparing the 2,"},{"Start":"05:54.750 ","End":"05:57.830","Text":"we see there\u0027s less of these ends here,"},{"Start":"05:57.830 ","End":"06:00.125","Text":"more of them here; less of these ends here,"},{"Start":"06:00.125 ","End":"06:04.500","Text":"more of them here; less of these amylopectin with starch, more of them here."},{"Start":"06:04.500 ","End":"06:09.620","Text":"It means there are more available units of glucose to be utilized for"},{"Start":"06:09.620 ","End":"06:15.550","Text":"energy in the glycogen molecule than in the starch amylopectin molecule."},{"Start":"06:15.550 ","End":"06:22.025","Text":"Basically, what we see here are macromolecular structures of amylopectin and glycogen."},{"Start":"06:22.025 ","End":"06:26.840","Text":"Amylopectin has a single reducing and an Alpha-1,6 branch points"},{"Start":"06:26.840 ","End":"06:33.035","Text":"about once every 15-30 or more commonly 24-30 glucose residues."},{"Start":"06:33.035 ","End":"06:38.675","Text":"In contrast, glycogen has branch points about every 8-12 glucose residues."},{"Start":"06:38.675 ","End":"06:42.564","Text":"These residues, we can count them and you\u0027ll have 8-12, 1,"},{"Start":"06:42.564 ","End":"06:44.384","Text":"2, 3, 4, 5, 6,"},{"Start":"06:44.384 ","End":"06:46.959","Text":"7, 8 branch, etc.,"},{"Start":"06:46.959 ","End":"06:51.410","Text":"and it has a glycogenin homo dimeric core protein,"},{"Start":"06:51.410 ","End":"06:54.860","Text":"so it\u0027s a dimer of the same unit and,"},{"Start":"06:54.860 ","End":"06:58.474","Text":"with 2 glucose molecules at the center,"},{"Start":"06:58.474 ","End":"07:00.120","Text":"the increased number of Alpha-1,"},{"Start":"07:00.120 ","End":"07:03.170","Text":"6 branch points and glycogen compared to that"},{"Start":"07:03.170 ","End":"07:06.845","Text":"amylopectin results in a much larger number of non-reducing ends."},{"Start":"07:06.845 ","End":"07:10.730","Text":"There\u0027s more blue ends than here if we counted here versus here,"},{"Start":"07:10.730 ","End":"07:13.280","Text":"there\u0027s many more here as indicated with"},{"Start":"07:13.280 ","End":"07:18.500","Text":"a dark blue ellipses which represent the hexagon."},{"Start":"07:18.500 ","End":"07:21.915","Text":"It should be this shape in reality."},{"Start":"07:21.915 ","End":"07:24.410","Text":"Koosh ball is analogous to amylopectin and glycogen"},{"Start":"07:24.410 ","End":"07:27.710","Text":"core and a way to hopefully have you visualize it"},{"Start":"07:27.710 ","End":"07:31.400","Text":"and remember better so that you see"},{"Start":"07:31.400 ","End":"07:33.950","Text":"the particles with the difference being the number of"},{"Start":"07:33.950 ","End":"07:37.430","Text":"fingers representing the non-reducing ends."},{"Start":"07:37.430 ","End":"07:42.335","Text":"With this, we completed part 2 of homopolysaccharides for fuel,"},{"Start":"07:42.335 ","End":"07:45.380","Text":"where we specifically talked about glycogen and covered"},{"Start":"07:45.380 ","End":"07:50.135","Text":"the energy storage polysaccharide glycogen and characteristics of glycogen."},{"Start":"07:50.135 ","End":"07:56.460","Text":"From here, we will continue on talking on homopolysaccharides in the next part."}],"ID":30505},{"Watched":false,"Name":"Homopolysaccharides Part 3","Duration":"6m 55s","ChapterTopicVideoID":28962,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.725","Text":"Welcome back to homopolysaccharides for fuel part 3."},{"Start":"00:04.725 ","End":"00:07.935","Text":"In this section, we will learn about a third type of"},{"Start":"00:07.935 ","End":"00:10.995","Text":"energy storage polysaccharide named"},{"Start":"00:10.995 ","End":"00:14.609","Text":"dextran and we\u0027ll learn about the characteristics of dextran."},{"Start":"00:14.609 ","End":"00:17.111","Text":"As we go over this section,"},{"Start":"00:17.111 ","End":"00:22.695","Text":"think of the different homopolysaccharides for fuel that we talked about."},{"Start":"00:22.695 ","End":"00:24.495","Text":"We started with starch,"},{"Start":"00:24.495 ","End":"00:26.265","Text":"we\u0027ve talked about glycogen,"},{"Start":"00:26.265 ","End":"00:28.364","Text":"and now we\u0027re moving into dextran."},{"Start":"00:28.364 ","End":"00:31.620","Text":"Again, try to keep in mind the characteristics we talked about with"},{"Start":"00:31.620 ","End":"00:34.965","Text":"the previous ones as we talk about dextran."},{"Start":"00:34.965 ","End":"00:37.680","Text":"The storage of glucose as starch greatly"},{"Start":"00:37.680 ","End":"00:42.150","Text":"reduces the large intracellular osmotic pressure that would"},{"Start":"00:42.150 ","End":"00:45.980","Text":"result from its storage in monomeric form because osmotic pressure is"},{"Start":"00:45.980 ","End":"00:50.225","Text":"proportional to the number of solute molecules in a given volume."},{"Start":"00:50.225 ","End":"00:52.220","Text":"Starch is a reducing sugar,"},{"Start":"00:52.220 ","End":"00:58.760","Text":"although it has only 1 residue called the reducing end that lacks a glycosidic bond."},{"Start":"00:58.760 ","End":"01:02.870","Text":"If we think of it, if osmotic pressure is"},{"Start":"01:02.870 ","End":"01:09.835","Text":"proportional to the number of solute molecules,"},{"Start":"01:09.835 ","End":"01:12.800","Text":"if we have glucose,"},{"Start":"01:12.800 ","End":"01:15.575","Text":"starch, or glycogen,"},{"Start":"01:15.575 ","End":"01:21.980","Text":"let\u0027s say our glycogen is made of 1,000 units of glucose,"},{"Start":"01:21.980 ","End":"01:23.705","Text":"let\u0027s say our starch,"},{"Start":"01:23.705 ","End":"01:27.290","Text":"because it\u0027s less branched and less compact,"},{"Start":"01:27.290 ","End":"01:29.935","Text":"let\u0027s say it will have 100."},{"Start":"01:29.935 ","End":"01:34.070","Text":"This is not in any regard the relation of the proportional onto each"},{"Start":"01:34.070 ","End":"01:39.560","Text":"other and we have 100 glucose units."},{"Start":"01:39.560 ","End":"01:45.290","Text":"What it means is that the osmotic pressure of the cell"},{"Start":"01:45.290 ","End":"01:51.550","Text":"that has 100 glucose units actually has 100 molecules."},{"Start":"01:51.550 ","End":"01:54.560","Text":"These 100 glucose units or monomers,"},{"Start":"01:54.560 ","End":"01:56.390","Text":"you have 100 molecules."},{"Start":"01:56.390 ","End":"02:00.110","Text":"If we\u0027re looking at the starch that has the same number of glucose units,"},{"Start":"02:00.110 ","End":"02:06.140","Text":"but it is in a branch chain as an amylopectin,"},{"Start":"02:06.140 ","End":"02:10.115","Text":"you actually have 1 molecule."},{"Start":"02:10.115 ","End":"02:13.975","Text":"If you have the glycogen,"},{"Start":"02:13.975 ","End":"02:17.330","Text":"a chain of 1,000 because it\u0027s higher,"},{"Start":"02:17.330 ","End":"02:19.310","Text":"it\u0027s more highly branched and more compact,"},{"Start":"02:19.310 ","End":"02:21.680","Text":"again, you\u0027ll have 1 molecule."},{"Start":"02:21.680 ","End":"02:27.754","Text":"Actually, even though these 2 have the same amount of glucose units,"},{"Start":"02:27.754 ","End":"02:32.450","Text":"this has osmotic pressure of 100 to 1 because there are"},{"Start":"02:32.450 ","End":"02:38.285","Text":"100 molecules versus 1 starch molecule, 1 solute molecule."},{"Start":"02:38.285 ","End":"02:39.710","Text":"On the other hand,"},{"Start":"02:39.710 ","End":"02:42.290","Text":"when we\u0027re looking at these 2 molecules,"},{"Start":"02:42.290 ","End":"02:47.735","Text":"we have starch being with less units of glucose."},{"Start":"02:47.735 ","End":"02:50.705","Text":"Glycogen has 10 times more glucose units."},{"Start":"02:50.705 ","End":"02:56.300","Text":"The osmotic pressure of them is the same because the unit,"},{"Start":"02:56.300 ","End":"03:01.355","Text":"the molecule is made of this chain of 100 units versus 1,000 units."},{"Start":"03:01.355 ","End":"03:07.625","Text":"Therefore, storage of glucose as starch greatly reduces"},{"Start":"03:07.625 ","End":"03:14.510","Text":"this intracellular osmotic pressure and allows for starch as a reducing sugar,"},{"Start":"03:14.510 ","End":"03:18.140","Text":"although it has only 1 residue called the reducing end to"},{"Start":"03:18.140 ","End":"03:22.175","Text":"allow for a lot of energy to be stored."},{"Start":"03:22.175 ","End":"03:27.195","Text":"Now, similarly, why not store glucose in its monomeric form?"},{"Start":"03:27.195 ","End":"03:31.715","Text":"It has been calculated that hepatocytes store glycogen"},{"Start":"03:31.715 ","End":"03:36.425","Text":"equivalent to a glucose concentration of 0.4 molarity."},{"Start":"03:36.425 ","End":"03:39.215","Text":"The actual concentration of glycogen,"},{"Start":"03:39.215 ","End":"03:44.630","Text":"which is insoluble and contributes little to the osmolarity of"},{"Start":"03:44.630 ","End":"03:51.025","Text":"the cytosol is about 0.01 molar."},{"Start":"03:51.025 ","End":"03:57.095","Text":"So 0.01 molar versus to the equivalent of 0.4 molar."},{"Start":"03:57.095 ","End":"04:02.115","Text":"This is a whole decimal point larger and times 4."},{"Start":"04:02.115 ","End":"04:07.925","Text":"If the cytosol contain 0.4 molar of glucose,"},{"Start":"04:07.925 ","End":"04:11.420","Text":"the osmolarity would be threateningly high,"},{"Start":"04:11.420 ","End":"04:15.665","Text":"leading to osmotic entry of water that might rupture the cell."},{"Start":"04:15.665 ","End":"04:20.510","Text":"Furthermore, with an intracellular glucose concentration of 0.4 molar and"},{"Start":"04:20.510 ","End":"04:25.887","Text":"an external concentration of about 5 millimolar,"},{"Start":"04:25.887 ","End":"04:29.615","Text":"and milli a decimal below molar,"},{"Start":"04:29.615 ","End":"04:34.327","Text":"which is the concentration in the blood of a mammal,"},{"Start":"04:34.327 ","End":"04:39.260","Text":"the free energy change for glucose uptake into cells against"},{"Start":"04:39.260 ","End":"04:45.675","Text":"this very high concentration gradient would be prohibitively large."},{"Start":"04:45.675 ","End":"04:54.125","Text":"All this is to say that glycogen and starch are very efficient forms of energy storage."},{"Start":"04:54.125 ","End":"04:58.710","Text":"Now the third form is dextrans."},{"Start":"04:58.710 ","End":"05:03.113","Text":"Dextrans are bacteria and yeast polysaccharides,"},{"Start":"05:03.113 ","End":"05:08.910","Text":"homopolysaccharides, made up of Alpha-1,6-linked poly-D-glucose."},{"Start":"05:08.910 ","End":"05:14.200","Text":"This linkage is like the branch points in amylopectin and glycogen."},{"Start":"05:14.200 ","End":"05:20.610","Text":"All have Alpha-1,3 branches and some also have Alpha-1,2 or Alpha-1,4 branches."},{"Start":"05:20.610 ","End":"05:25.100","Text":"In this case, it\u0027s the opposite in a way"},{"Start":"05:25.100 ","End":"05:30.905","Text":"than glycogen and amylopectin than the starch where the chain,"},{"Start":"05:30.905 ","End":"05:36.830","Text":"the glucose, the polysaccharide chain is made of Alpha-1,6-links,"},{"Start":"05:36.830 ","End":"05:40.275","Text":"while the branch points are in some,"},{"Start":"05:40.275 ","End":"05:44.470","Text":"you have the Alpha-1,4 like the chains that we see in glycogen and amylopectin,"},{"Start":"05:44.470 ","End":"05:51.955","Text":"or Alpha-1,2, and all of them have the Alpha-1,3-link branches."},{"Start":"05:51.955 ","End":"05:58.750","Text":"Dextrans also provide a source of glucose for bacterial metabolism."},{"Start":"05:58.750 ","End":"06:01.840","Text":"Now, dental plaques formed by bacteria growing on"},{"Start":"06:01.840 ","End":"06:04.960","Text":"the surface of teeth are rich in dextrans."},{"Start":"06:04.960 ","End":"06:09.280","Text":"Dental plaque formed by bacteria growing on the surface of teeth, for example,"},{"Start":"06:09.280 ","End":"06:11.830","Text":"is rich in dextrans which are adhesive and"},{"Start":"06:11.830 ","End":"06:15.400","Text":"allow the bacteria to stick to teeth and to each other."},{"Start":"06:15.400 ","End":"06:19.720","Text":"Also synthetic dextrans are used in various commercial products."},{"Start":"06:19.720 ","End":"06:26.315","Text":"So dextrans are used for metabolism and also utilized by bacteria."},{"Start":"06:26.315 ","End":"06:27.710","Text":"For example, as mentioned,"},{"Start":"06:27.710 ","End":"06:33.310","Text":"dental plaque to provide an adhesive for the bacteria to stick to the teeth,"},{"Start":"06:33.310 ","End":"06:38.000","Text":"so they can then utilize molecules found in-between"},{"Start":"06:38.000 ","End":"06:43.120","Text":"the teeth along the teeth to break these down for energy usage."},{"Start":"06:43.120 ","End":"06:48.560","Text":"With this, we completed the lesson on homopolysaccharides for fuel and"},{"Start":"06:48.560 ","End":"06:51.080","Text":"we covered the types of energy storage polysaccharides and"},{"Start":"06:51.080 ","End":"06:54.690","Text":"the characteristics of such polysaccharides."}],"ID":30506},{"Watched":false,"Name":"Exercise 4","Duration":"1m 10s","ChapterTopicVideoID":28955,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.610","Text":"Welcome to an exercise carrying the lesson on homopolysaccharides that function as fuel."},{"Start":"00:05.610 ","End":"00:09.195","Text":"What are the 3 types of polysaccharides mentioned in the lesson,"},{"Start":"00:09.195 ","End":"00:10.635","Text":"and where are they found?"},{"Start":"00:10.635 ","End":"00:12.105","Text":"In what organisms?"},{"Start":"00:12.105 ","End":"00:15.300","Text":"These are the polysaccharides that provide fuel."},{"Start":"00:15.300 ","End":"00:18.600","Text":"The first one that was mentioned as glycogen."},{"Start":"00:18.600 ","End":"00:21.675","Text":"It is the main storage polysaccharide of animal cells."},{"Start":"00:21.675 ","End":"00:23.400","Text":"It is present in all cells."},{"Start":"00:23.400 ","End":"00:26.190","Text":"It is especially abundant in the liver where it may"},{"Start":"00:26.190 ","End":"00:30.855","Text":"constitute as much as 7 percent of the wet weight,"},{"Start":"00:30.855 ","End":"00:32.830","Text":"and in skeletal muscle."},{"Start":"00:32.830 ","End":"00:35.075","Text":"The second one is starch."},{"Start":"00:35.075 ","End":"00:37.280","Text":"This is the principal energy reserve in"},{"Start":"00:37.280 ","End":"00:41.795","Text":"most plant cells and is especially abundant in tubers,"},{"Start":"00:41.795 ","End":"00:46.355","Text":"underground stems such as potatoes and in seeds."},{"Start":"00:46.355 ","End":"00:51.365","Text":"The third and last type that we mentioned is dextrin."},{"Start":"00:51.365 ","End":"00:55.580","Text":"These are bacterial and yeast polysaccharides and they"},{"Start":"00:55.580 ","End":"01:00.010","Text":"provide a source of glucose for bacterial metabolism."},{"Start":"01:00.010 ","End":"01:04.295","Text":"The 3 types that we mentioned are glycogen in animals,"},{"Start":"01:04.295 ","End":"01:09.780","Text":"starch in plants, and dextrin in bacteria and yeast."}],"ID":30507},{"Watched":false,"Name":"Exercise 5","Duration":"2m 30s","ChapterTopicVideoID":28956,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.725","Text":"Welcome back to another exercise on homopolysaccharides as fuel."},{"Start":"00:04.725 ","End":"00:06.105","Text":"Fill in the blanks."},{"Start":"00:06.105 ","End":"00:10.830","Text":"1, the most important storage polysaccharides are blank in plant cells,"},{"Start":"00:10.830 ","End":"00:12.825","Text":"and blank in animal cells."},{"Start":"00:12.825 ","End":"00:19.740","Text":"2, both polysaccharides occur blank location as large clusters or blank."},{"Start":"00:19.740 ","End":"00:24.975","Text":"3, starch and glycogen molecules are heavily blank."},{"Start":"00:24.975 ","End":"00:27.990","Text":"Let\u0027s start with 1."},{"Start":"00:27.990 ","End":"00:33.015","Text":"The most important storage polysaccharides are blank in plant cells,"},{"Start":"00:33.015 ","End":"00:34.835","Text":"and blank in animal cells."},{"Start":"00:34.835 ","End":"00:37.175","Text":"Well, we mentioned 2."},{"Start":"00:37.175 ","End":"00:40.385","Text":"These are terms that for sure one of them,"},{"Start":"00:40.385 ","End":"00:44.930","Text":"you are familiar from top of food and diet."},{"Start":"00:44.930 ","End":"00:48.905","Text":"The polysaccharide that is in plant cells,"},{"Start":"00:48.905 ","End":"00:52.525","Text":"we had mentioned 3 types."},{"Start":"00:52.525 ","End":"00:58.110","Text":"We mentioned glycogen, starch, and dextrin."},{"Start":"00:58.110 ","End":"01:04.415","Text":"So plant cells that would be starch,"},{"Start":"01:04.415 ","End":"01:07.015","Text":"which leaves us with the glycogen or dextrin."},{"Start":"01:07.015 ","End":"01:12.050","Text":"Dextrin we said is in bacteria and yeast and so for animal cells,"},{"Start":"01:12.050 ","End":"01:16.913","Text":"are polysaccharide first storage is glycogen has."},{"Start":"01:16.913 ","End":"01:23.000","Text":"For 2 both polysaccharides occur in what location as large clusters or blank."},{"Start":"01:23.000 ","End":"01:26.330","Text":"Well, both polysaccharides,"},{"Start":"01:26.330 ","End":"01:28.595","Text":"what location do they have?"},{"Start":"01:28.595 ","End":"01:31.385","Text":"They are in plant cells or an animal cells?"},{"Start":"01:31.385 ","End":"01:41.950","Text":"Therefore, they both occur intracellularly as large clusters or granules."},{"Start":"01:41.950 ","End":"01:47.435","Text":"They are within the cells and are in clusters or granules."},{"Start":"01:47.435 ","End":"01:50.900","Text":"3, starch and glycogen hint,"},{"Start":"01:50.900 ","End":"01:53.555","Text":"this was our answer here."},{"Start":"01:53.555 ","End":"01:58.085","Text":"Starch and glycogen molecules are heavily, what?"},{"Start":"01:58.085 ","End":"02:03.140","Text":"Now, we talked about their molecules and what it allows to occur,"},{"Start":"02:03.140 ","End":"02:06.169","Text":"and that is they are heavily hydrated,"},{"Start":"02:06.169 ","End":"02:11.000","Text":"and this is due to their ability to have hydrogen bonds."},{"Start":"02:11.000 ","End":"02:12.860","Text":"Let\u0027s go over this."},{"Start":"02:12.860 ","End":"02:15.920","Text":"1, the most important storage polysaccharides are"},{"Start":"02:15.920 ","End":"02:19.015","Text":"starch in plant cells and glycogen in animal cells."},{"Start":"02:19.015 ","End":"02:24.725","Text":"2, both these polysaccharides occur intracellularly as large clusters or granules,"},{"Start":"02:24.725 ","End":"02:30.390","Text":"and 3 starch and glycogen molecules are heavily hydrated."}],"ID":30508},{"Watched":false,"Name":"Exercise 6","Duration":"41s","ChapterTopicVideoID":28957,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.155","Text":"What did we learn about homopolysaccharides as fuel?"},{"Start":"00:04.155 ","End":"00:06.630","Text":"One of things we talked about is starch."},{"Start":"00:06.630 ","End":"00:08.295","Text":"Define the term starch."},{"Start":"00:08.295 ","End":"00:11.970","Text":"Starch is an important storage polysaccharide in plant cells."},{"Start":"00:11.970 ","End":"00:14.700","Text":"It\u0027s composed of a mixture of glycans that plants"},{"Start":"00:14.700 ","End":"00:17.730","Text":"synthesize as their principal energy reserve,"},{"Start":"00:17.730 ","End":"00:20.730","Text":"which is especially abundant in tubers,"},{"Start":"00:20.730 ","End":"00:25.365","Text":"underground stems, such as potatoes and seeds, etc."},{"Start":"00:25.365 ","End":"00:28.679","Text":"It contains 2 types of glucose polymers,"},{"Start":"00:28.679 ","End":"00:30.735","Text":"amylose and amylopectin,"},{"Start":"00:30.735 ","End":"00:33.300","Text":"and we further describe these 2."},{"Start":"00:33.300 ","End":"00:39.910","Text":"Try to remember what the differences are between these 2 types of chains."}],"ID":30509},{"Watched":false,"Name":"Exercise 7","Duration":"5m 58s","ChapterTopicVideoID":28958,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.430","Text":"We have another question to attack within homopolysaccharides as fuel."},{"Start":"00:05.430 ","End":"00:07.815","Text":"Which statement is false?"},{"Start":"00:07.815 ","End":"00:11.655","Text":"A, the primary structure of glycogen is similar to amylopectin,"},{"Start":"00:11.655 ","End":"00:13.335","Text":"yet is more highly branched."},{"Start":"00:13.335 ","End":"00:16.620","Text":"B, the storage of glucose as starch greatly reduces"},{"Start":"00:16.620 ","End":"00:19.350","Text":"the large intracellular osmotic pressure that would"},{"Start":"00:19.350 ","End":"00:23.130","Text":"result from its storage in monomeric form."},{"Start":"00:23.130 ","End":"00:29.029","Text":"C, glycogen is highly branched structure which has many reducing ends,"},{"Start":"00:29.029 ","End":"00:32.970","Text":"permits the rapid utilization of glucose in time of metabolic need."},{"Start":"00:32.970 ","End":"00:36.780","Text":"D, glycogen granules contain tightly bound form"},{"Start":"00:36.780 ","End":"00:41.130","Text":"the enzymes responsible for the synthesis and degradation of glycogen."},{"Start":"00:41.130 ","End":"00:45.575","Text":"E, dental plaque is rich in dextrans which are adhesive"},{"Start":"00:45.575 ","End":"00:50.320","Text":"and allow the bacteria to stick to teeth and to each other."},{"Start":"00:50.320 ","End":"00:56.120","Text":"F, glycogen is present in all cells abundant in the liver and skeletal muscle."},{"Start":"00:56.120 ","End":"00:58.120","Text":"Let\u0027s start 1 at a time."},{"Start":"00:58.120 ","End":"01:02.795","Text":"A, the primary structure of glycogen is similar to amylopectin,"},{"Start":"01:02.795 ","End":"01:05.705","Text":"yet it\u0027s more highly branched."},{"Start":"01:05.705 ","End":"01:12.155","Text":"Amylopectin was mentioned as 1 of the forms of starch."},{"Start":"01:12.155 ","End":"01:15.980","Text":"Yes, it is similar to amylopectin,"},{"Start":"01:15.980 ","End":"01:18.740","Text":"yet more highly branched therefore this is"},{"Start":"01:18.740 ","End":"01:23.195","Text":"a correct statement and therefore it\u0027s false and it is not our answer."},{"Start":"01:23.195 ","End":"01:28.250","Text":"Let\u0027s go to B. The storage of glucose as starch greatly reduces"},{"Start":"01:28.250 ","End":"01:31.400","Text":"the large intracellular osmotic pressure that would"},{"Start":"01:31.400 ","End":"01:35.090","Text":"result from its storage in monomeric form."},{"Start":"01:35.090 ","End":"01:37.730","Text":"Now, because osmotic pressure is proportional to the number of"},{"Start":"01:37.730 ","End":"01:40.970","Text":"solute molecules in a given volume,"},{"Start":"01:40.970 ","End":"01:45.920","Text":"the minute these monomeric forms are turned it into"},{"Start":"01:45.920 ","End":"01:51.690","Text":"a polysaccharide that is actually 1 solute molecule,"},{"Start":"01:51.690 ","End":"01:57.785","Text":"it does mean that the osmotic pressure is less."},{"Start":"01:57.785 ","End":"02:06.260","Text":"Therefore, this is a true statement and thus is not our answer."},{"Start":"02:06.260 ","End":"02:10.085","Text":"C, glycogen is highly branched structure."},{"Start":"02:10.085 ","End":"02:15.665","Text":"We said it\u0027s more highly branched than amylopectin which is a starch molecule."},{"Start":"02:15.665 ","End":"02:18.425","Text":"Glycogen is highly branched structure,"},{"Start":"02:18.425 ","End":"02:20.270","Text":"has many reducing ends permits"},{"Start":"02:20.270 ","End":"02:23.735","Text":"the rapid utilization of glucose in time of metabolic need."},{"Start":"02:23.735 ","End":"02:30.575","Text":"Well, these many ends are super important for the utilization of glucose so that"},{"Start":"02:30.575 ","End":"02:37.175","Text":"it can quickly attack all of these ends to break it down for the metabolic need,"},{"Start":"02:37.175 ","End":"02:42.285","Text":"but is this the true statement?"},{"Start":"02:42.285 ","End":"02:44.310","Text":"This one, we need to get back to."},{"Start":"02:44.310 ","End":"02:48.080","Text":"Lets go to D. Glycogen granules contain tightly bound form"},{"Start":"02:48.080 ","End":"02:51.845","Text":"the enzymes responsible for the synthesis and degradation of glycogen."},{"Start":"02:51.845 ","End":"02:56.520","Text":"This was mentioned and this is quite important for this ability,"},{"Start":"02:56.520 ","End":"03:00.275","Text":"and it\u0027s these enzymes that need to be used"},{"Start":"03:00.275 ","End":"03:04.655","Text":"to break down and utilize glucose from glycogen,"},{"Start":"03:04.655 ","End":"03:11.085","Text":"so this is true and therefore we are not choosing D."},{"Start":"03:11.085 ","End":"03:14.220","Text":"Let\u0027s go to E. Dental plaque is rich in"},{"Start":"03:14.220 ","End":"03:17.885","Text":"dextrans remember we mentioned dextrans for bacteria or yeast,"},{"Start":"03:17.885 ","End":"03:23.630","Text":"which are adhesive and allow the bacteria to stick to teeth and to each other."},{"Start":"03:23.630 ","End":"03:25.370","Text":"We did mention this."},{"Start":"03:25.370 ","End":"03:30.275","Text":"Dental plaque formed by bacteria growing on the surface of"},{"Start":"03:30.275 ","End":"03:35.480","Text":"teeth is rich in dextrans which are adhesive and allow the bacteria to stick,"},{"Start":"03:35.480 ","End":"03:37.100","Text":"to teach and to each other."},{"Start":"03:37.100 ","End":"03:41.720","Text":"This is something that bacteria do in order to further their ability to"},{"Start":"03:41.720 ","End":"03:47.195","Text":"stick to the teeth and utilize the teeth for their own needs and growth."},{"Start":"03:47.195 ","End":"03:49.760","Text":"This is true and therefore it is not a right answer."},{"Start":"03:49.760 ","End":"03:53.345","Text":"Let\u0027s go to F. Glycogen is present in all cells,"},{"Start":"03:53.345 ","End":"03:59.150","Text":"yet is especially abundant in the liver where it may constitute as much as 7 percent of"},{"Start":"03:59.150 ","End":"04:05.195","Text":"the wet weight and in skeletal muscle where occurs as cytoplasmic granules."},{"Start":"04:05.195 ","End":"04:06.785","Text":"This for sure is true,"},{"Start":"04:06.785 ","End":"04:09.620","Text":"so it\u0027s not F. What makes C?"},{"Start":"04:09.620 ","End":"04:11.120","Text":"Let\u0027s go over this again."},{"Start":"04:11.120 ","End":"04:13.020","Text":"Glycogen is highly branched structure,"},{"Start":"04:13.020 ","End":"04:15.140","Text":"we know this is true because we compared it to"},{"Start":"04:15.140 ","End":"04:17.675","Text":"amylopectin saying it\u0027s more highly branched,"},{"Start":"04:17.675 ","End":"04:19.910","Text":"which has many reducing ends permits"},{"Start":"04:19.910 ","End":"04:22.850","Text":"the rapid utilization of glucose in time of metabolic need."},{"Start":"04:22.850 ","End":"04:26.240","Text":"This is true, as the money ends and it permits"},{"Start":"04:26.240 ","End":"04:30.005","Text":"the rapid utilization but where it isn\u0027t true,"},{"Start":"04:30.005 ","End":"04:32.765","Text":"it is not reducing ends."},{"Start":"04:32.765 ","End":"04:36.020","Text":"This is our correct answer because this is the false statement."},{"Start":"04:36.020 ","End":"04:39.140","Text":"Glycogen is highly bound structure which has many reducing ends, permits"},{"Start":"04:39.140 ","End":"04:42.530","Text":"the rapid digitalization of glucose in time of metabolic need."},{"Start":"04:42.530 ","End":"04:44.385","Text":"To make it correct,"},{"Start":"04:44.385 ","End":"04:47.090","Text":"we would need to say glycogen is highly branched structure,"},{"Start":"04:47.090 ","End":"04:49.550","Text":"which has many non-reducing ends,"},{"Start":"04:49.550 ","End":"04:54.590","Text":"permits the rapid utilization of glucose in time of metabolic need."},{"Start":"04:54.590 ","End":"05:00.710","Text":"Each branch in glycogen ends with a non-reducing sugar unit."},{"Start":"05:00.710 ","End":"05:03.470","Text":"The non-reducing ends of the amylopectin and"},{"Start":"05:03.470 ","End":"05:06.725","Text":"glycogen make it available for glucose retrieval."},{"Start":"05:06.725 ","End":"05:09.845","Text":"A glycogen molecule has many non-reducing ends,"},{"Start":"05:09.845 ","End":"05:13.415","Text":"as it has branches but only 1 reducing end."},{"Start":"05:13.415 ","End":"05:16.040","Text":"When glycogen is used as an energy source,"},{"Start":"05:16.040 ","End":"05:20.290","Text":"glucose units are removed 1 at a time from the non-reducing ends while"},{"Start":"05:20.290 ","End":"05:23.330","Text":"degradative enzymes that act only at"},{"Start":"05:23.330 ","End":"05:27.244","Text":"non-reducing ends can work simultaneously on many branches,"},{"Start":"05:27.244 ","End":"05:31.205","Text":"speeding the conversion of the polymer to monosaccharides."},{"Start":"05:31.205 ","End":"05:38.615","Text":"It can convert and breakdown and utilize the glucose units of the polymer,"},{"Start":"05:38.615 ","End":"05:43.865","Text":"and this makes it very efficient in time of metabolic need."},{"Start":"05:43.865 ","End":"05:50.650","Text":"But again, it\u0027s the non-reducing ends because it has 1 reducing end."},{"Start":"05:50.650 ","End":"05:58.229","Text":"This is not what is utilized by the enzymes for the glucose molecules."}],"ID":30510},{"Watched":false,"Name":"Exercise 8","Duration":"1m 39s","ChapterTopicVideoID":28959,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.278","Text":"Let\u0027s cover another exercise within homopolysaccharides as a form of fuel."},{"Start":"00:04.278 ","End":"00:08.655","Text":"Mention and define the 2 types of polymers in starch."},{"Start":"00:08.655 ","End":"00:14.650","Text":"Starch contains 2 types of glucose polymers, Amylase and amylopectin."},{"Start":"00:15.500 ","End":"00:18.705","Text":"Amylose is a linear polymer that consists of"},{"Start":"00:18.705 ","End":"00:24.895","Text":"long unbranched chains of D-glucose residues connected by Alpha-1, 4 linkages."},{"Start":"00:24.895 ","End":"00:30.405","Text":"Maltose is an example of an amylose."},{"Start":"00:30.405 ","End":"00:35.760","Text":"It is made of several thousand glucose residues."},{"Start":"00:35.800 ","End":"00:41.000","Text":"Such chains vary in molecular weight from a few thousand to more than a"},{"Start":"00:41.000 ","End":"00:46.760","Text":"million because of the variability in the size."},{"Start":"00:46.760 ","End":"00:49.085","Text":"Amylopectin, on the other hand,"},{"Start":"00:49.085 ","End":"00:52.040","Text":"is a highly branched molecule with Alpha-1,"},{"Start":"00:52.040 ","End":"00:54.229","Text":"4 glycosidic linkages,"},{"Start":"00:54.229 ","End":"01:00.820","Text":"similar to amylose, but it\u0027s highly branched versus amylose that\u0027s unbranched."},{"Start":"01:00.820 ","End":"01:04.025","Text":"These linkages joining successive glucose residues"},{"Start":"01:04.025 ","End":"01:06.455","Text":"in its chains with a branch points occurring"},{"Start":"01:06.455 ","End":"01:12.850","Text":"every 24-30 residues that are Alpha-1, 6 linkages."},{"Start":"01:12.850 ","End":"01:20.104","Text":"You have amylose that is unbranched and amylopectin that is highly branched."},{"Start":"01:20.104 ","End":"01:23.899","Text":"These are the 2 types of polymers in starch."},{"Start":"01:23.899 ","End":"01:29.450","Text":"Amylopectin has a high molecular weight of up to 200 million,"},{"Start":"01:29.450 ","End":"01:34.010","Text":"making these some of the largest molecules in nature and the contribution"},{"Start":"01:34.010 ","End":"01:37.580","Text":"to this is due to the many branches,"},{"Start":"01:37.580 ","End":"01:39.780","Text":"and there you have it."}],"ID":30511},{"Watched":false,"Name":"Homopolysaccharides - Structure Part 1","Duration":"10m 27s","ChapterTopicVideoID":28963,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:03.615","Text":"We\u0027re still within the topic of Polysaccharides."},{"Start":"00:03.615 ","End":"00:10.875","Text":"In this section, we\u0027re going to talk about homopolysaccharides that serve as structure,"},{"Start":"00:10.875 ","End":"00:13.035","Text":"they play a structural role."},{"Start":"00:13.035 ","End":"00:15.360","Text":"In this section, we will learn about the types of"},{"Start":"00:15.360 ","End":"00:19.245","Text":"structural polysaccharides and characteristics of such polysaccharides."},{"Start":"00:19.245 ","End":"00:21.870","Text":"We\u0027re going to split this lesson into 3 parts."},{"Start":"00:21.870 ","End":"00:24.825","Text":"We\u0027re going to start with part 1 of"},{"Start":"00:24.825 ","End":"00:29.465","Text":"homopolysaccharides that are structural and in this section,"},{"Start":"00:29.465 ","End":"00:35.015","Text":"we will learn about cellulose structure and the characteristics of cellulose."},{"Start":"00:35.015 ","End":"00:39.060","Text":"Some homopolysaccharides serve structural roles."},{"Start":"00:39.060 ","End":"00:41.469","Text":"We\u0027ve talked about homopolysaccharides already,"},{"Start":"00:41.469 ","End":"00:46.340","Text":"homopolysaccharides are polysaccharides that are made of the same type of"},{"Start":"00:46.340 ","End":"00:51.675","Text":"unit and they could be linear or branched versus the heteropolysaccharides."},{"Start":"00:51.675 ","End":"00:57.480","Text":"We are now talking about homopolysaccharides that serve structural roles."},{"Start":"00:57.480 ","End":"00:59.600","Text":"The first term of polysaccharide that serves"},{"Start":"00:59.600 ","End":"01:02.600","Text":"structural role that we will talk about is cellulose."},{"Start":"01:02.600 ","End":"01:04.505","Text":"It\u0027s a fibrous, tough,"},{"Start":"01:04.505 ","End":"01:07.010","Text":"water insoluble substance,"},{"Start":"01:07.010 ","End":"01:11.900","Text":"is found as the core component in the cell wall of plants."},{"Start":"01:11.900 ","End":"01:13.835","Text":"You have a plant,"},{"Start":"01:13.835 ","End":"01:16.070","Text":"its cells aside from the membrane,"},{"Start":"01:16.070 ","End":"01:20.375","Text":"have a wall, a cell wall, this thicker,"},{"Start":"01:20.375 ","End":"01:24.275","Text":"more rigid, tough outer coating,"},{"Start":"01:24.275 ","End":"01:30.060","Text":"and it is made of cellulose fibers."},{"Start":"01:30.060 ","End":"01:35.210","Text":"Cellulose is the core component in the cell walls of all plants,"},{"Start":"01:35.210 ","End":"01:38.270","Text":"particularly in stocks, stems, trunks,"},{"Start":"01:38.270 ","End":"01:40.820","Text":"and all the woody portions of the plant body,"},{"Start":"01:40.820 ","End":"01:42.485","Text":"the harder, more thick."},{"Start":"01:42.485 ","End":"01:46.460","Text":"It can withstand osmotic pressure differences between"},{"Start":"01:46.460 ","End":"01:52.040","Text":"the extracellular and intracellular spaces of up to 20 atmospheres."},{"Start":"01:52.040 ","End":"01:55.985","Text":"Remember the idea of osmotic pressure is if you"},{"Start":"01:55.985 ","End":"02:01.070","Text":"have a lot more components inside the cell,"},{"Start":"02:01.070 ","End":"02:06.275","Text":"it will be more concentrated so water will want to enter."},{"Start":"02:06.275 ","End":"02:09.800","Text":"But then if you have too much water entering,"},{"Start":"02:09.800 ","End":"02:11.495","Text":"it can expand and burst."},{"Start":"02:11.495 ","End":"02:17.690","Text":"These cell walls can actually withstand osmotic pressure so that you can get a lot of"},{"Start":"02:17.690 ","End":"02:24.335","Text":"water in and actually not burst with up to 20 atmospheres of pressure."},{"Start":"02:24.335 ","End":"02:29.870","Text":"Cellulose consists much of the massive wood and cotton,"},{"Start":"02:29.870 ","End":"02:33.350","Text":"which are almost pure cellulose."},{"Start":"02:33.350 ","End":"02:39.395","Text":"It is by far the most abundant carbohydrate on Earth,"},{"Start":"02:39.395 ","End":"02:45.725","Text":"it accounts for over half of the carbon in the biosphere."},{"Start":"02:45.725 ","End":"02:48.257","Text":"Remember the term biosphere,"},{"Start":"02:48.257 ","End":"02:51.455","Text":"biosphere is the region of the Earth that is actually covered in"},{"Start":"02:51.455 ","End":"02:54.840","Text":"organisms where there\u0027s living things,"},{"Start":"02:54.840 ","End":"03:00.890","Text":"and I said more than 50 percent of the carbon in the biosphere in the Earth"},{"Start":"03:00.890 ","End":"03:08.385","Text":"where organisms live is accounted by cellulose as the carbohydrate."},{"Start":"03:08.385 ","End":"03:11.885","Text":"Again, you have the plants, you have the cells, the cell wall,"},{"Start":"03:11.885 ","End":"03:16.190","Text":"this rigid cell wall is made of cellulose fibers."},{"Start":"03:16.190 ","End":"03:22.985","Text":"In the cellulose, you see the cellulose chains that come together to form these fibers."},{"Start":"03:22.985 ","End":"03:25.790","Text":"Then you have the macro fibrils,"},{"Start":"03:25.790 ","End":"03:30.500","Text":"which are basically many of these coming"},{"Start":"03:30.500 ","End":"03:35.690","Text":"together and forming the cell wall as they line up."},{"Start":"03:35.690 ","End":"03:38.750","Text":"Like analysts and the main chains of amylopectin and glycogen,"},{"Start":"03:38.750 ","End":"03:43.580","Text":"which we introduced in the previous lesson as homopolysaccharides for fuel,"},{"Start":"03:43.580 ","End":"03:48.975","Text":"the cellulose molecule is a linear, unbranched homopolysaccharides,"},{"Start":"03:48.975 ","End":"03:50.425","Text":"as seen here,"},{"Start":"03:50.425 ","End":"03:55.241","Text":"consisting of a thousand repeating units of cellbiose."},{"Start":"03:55.241 ","End":"04:03.120","Text":"You have the same unit that is repeating in a linear chain and it is not branched."},{"Start":"04:03.120 ","End":"04:08.240","Text":"Cellulose is a linear unbranched homopolysaccharide consisting of"},{"Start":"04:08.240 ","End":"04:14.540","Text":"nearly a thousand repeating units of a disaccharide called cellbiose,"},{"Start":"04:14.540 ","End":"04:21.015","Text":"so repeating units of cellbiose."},{"Start":"04:21.015 ","End":"04:28.170","Text":"Cellbiose consists of 2 glucose residues linked by Beta-1,4"},{"Start":"04:28.170 ","End":"04:35.600","Text":"glycosidic bonds totaling in 10,000-15,000 D-glucose units."},{"Start":"04:35.600 ","End":"04:39.810","Text":"Now, this just defines the type of bond,"},{"Start":"04:39.810 ","End":"04:41.390","Text":"it\u0027s a Beta-1,4,"},{"Start":"04:41.390 ","End":"04:44.930","Text":"it comes between the 1 and the 4,"},{"Start":"04:44.930 ","End":"04:46.700","Text":"this refers to the carbon."},{"Start":"04:46.700 ","End":"04:50.105","Text":"Remember when we talked about structure,"},{"Start":"04:50.105 ","End":"04:51.920","Text":"we number the carbons,"},{"Start":"04:51.920 ","End":"04:53.690","Text":"so this is 1 carbon,"},{"Start":"04:53.690 ","End":"04:54.950","Text":"this is 2, 3,"},{"Start":"04:54.950 ","End":"04:56.255","Text":"4, 5, 6."},{"Start":"04:56.255 ","End":"05:00.000","Text":"Here, this is a similar molecule,"},{"Start":"05:00.000 ","End":"05:02.980","Text":"this is carbon 1."},{"Start":"05:03.380 ","End":"05:06.150","Text":"If this is carbon 1,"},{"Start":"05:06.150 ","End":"05:09.600","Text":"it is bound to number 4 of this other 1,"},{"Start":"05:09.600 ","End":"05:12.860","Text":"so it\u0027s Beta-1,4 link D-glucose units."},{"Start":"05:12.860 ","End":"05:16.700","Text":"Now, just to signify the way it\u0027s written here,"},{"Start":"05:16.700 ","End":"05:25.075","Text":"this is another way to say a Beta-1-4 link versus a Beta-1,4 glycosidic bond."},{"Start":"05:25.075 ","End":"05:29.090","Text":"This is what it means that the 1 carbon that\u0027s"},{"Start":"05:29.090 ","End":"05:32.360","Text":"right here is bound to the 4 carbon that is"},{"Start":"05:32.360 ","End":"05:35.450","Text":"right here on the second molecule and this is what you"},{"Start":"05:35.450 ","End":"05:39.190","Text":"see here in the ball and stick figure."},{"Start":"05:39.190 ","End":"05:40.920","Text":"This is the carbon,"},{"Start":"05:40.920 ","End":"05:43.755","Text":"this is the oxygen,"},{"Start":"05:43.755 ","End":"05:48.705","Text":"carbon, oxygen, and this is the hydrogen."},{"Start":"05:48.705 ","End":"05:57.630","Text":"Carbon 1 with carbon 4 linked through the oxygen,"},{"Start":"05:57.630 ","End":"06:00.320","Text":"this is the glycosidic bonds."},{"Start":"06:00.320 ","End":"06:03.740","Text":"If you remember, glycosidic bonds form when you"},{"Start":"06:03.740 ","End":"06:08.074","Text":"have dehydration or water molecule is released."},{"Start":"06:08.074 ","End":"06:10.700","Text":"It would happen again if we\u0027re looking at this molecule,"},{"Start":"06:10.700 ","End":"06:15.170","Text":"this is the fourth carbon."},{"Start":"06:15.170 ","End":"06:17.840","Text":"If you had another 1 of these repeating here,"},{"Start":"06:17.840 ","End":"06:21.305","Text":"you\u0027d have the O right here,"},{"Start":"06:21.305 ","End":"06:25.850","Text":"just like here, that has a hydrogen to it."},{"Start":"06:25.850 ","End":"06:31.294","Text":"Basically, you would have this hydrogen"},{"Start":"06:31.294 ","End":"06:36.429","Text":"and this OH combine to form H_2O released."},{"Start":"06:36.429 ","End":"06:41.410","Text":"Then this O will be connected directly to carbon"},{"Start":"06:41.410 ","End":"06:48.380","Text":"4 and this O is connected to carbon 1 of the molecule over here."},{"Start":"06:48.470 ","End":"06:54.610","Text":"In other words, the glucose residues and cellulose are linked to by Beta-1,"},{"Start":"06:54.610 ","End":"06:59.235","Text":"4 glycosidic bonds in contrast to the Alpha-1 4 bonds of amylose,"},{"Start":"06:59.235 ","End":"07:01.140","Text":"starch, and glycogen."},{"Start":"07:01.140 ","End":"07:05.005","Text":"Cellulose, it is a Beta-1,4 glycosidic bonds,"},{"Start":"07:05.005 ","End":"07:06.414","Text":"whereas an amylose,"},{"Start":"07:06.414 ","End":"07:08.155","Text":"starch, and glycogen,"},{"Start":"07:08.155 ","End":"07:10.075","Text":"it is an Alpha-1,"},{"Start":"07:10.075 ","End":"07:15.910","Text":"4 bond, this is in amylose starch glycogen."},{"Start":"07:15.910 ","End":"07:17.810","Text":"The difference gives"},{"Start":"07:17.810 ","End":"07:21.770","Text":"cellulose and amylose very different structures and physical properties."},{"Start":"07:21.770 ","End":"07:27.110","Text":"Extra and other studies of cellulose fibers of cellulose chains are flat ribbons in which"},{"Start":"07:27.110 ","End":"07:33.275","Text":"successive glucose rings are turned over 180 degrees so they\u0027re basically flat."},{"Start":"07:33.275 ","End":"07:36.910","Text":"You see a little bit of dark angles,"},{"Start":"07:36.910 ","End":"07:39.380","Text":"but it is somewhat a flat unit,"},{"Start":"07:39.380 ","End":"07:43.460","Text":"there isn\u0027t much of moving around the planes and"},{"Start":"07:43.460 ","End":"07:49.690","Text":"the glucose rings are turned over 180 degrees with respect to each other."},{"Start":"07:49.690 ","End":"07:52.230","Text":"One is up here, for the other 1,"},{"Start":"07:52.230 ","End":"07:53.385","Text":"1 is down here,"},{"Start":"07:53.385 ","End":"07:56.740","Text":"it\u0027s a 180 degrees, it\u0027s rotated."},{"Start":"07:56.740 ","End":"08:00.950","Text":"This allows for hydrogen bonding between the glucose residues."},{"Start":"08:00.950 ","End":"08:04.625","Text":"There\u0027s the glucose between the carbon 1 and carbon 4."},{"Start":"08:04.625 ","End":"08:10.700","Text":"Parallel cellulose chains form sheets with interchain hydrogen bonds,"},{"Start":"08:10.700 ","End":"08:14.210","Text":"stacks of these sheets are held together by hydrogen bonds,"},{"Start":"08:14.210 ","End":"08:15.695","Text":"so these stack over each other."},{"Start":"08:15.695 ","End":"08:17.915","Text":"You see these, you have many of these,"},{"Start":"08:17.915 ","End":"08:21.080","Text":"they stack over each other and create"},{"Start":"08:21.080 ","End":"08:26.000","Text":"these hydrogen bonds as well as van der Waals interactions."},{"Start":"08:26.000 ","End":"08:30.410","Text":"This highly cohesive structure gives cellulose fibers exceptional strength and"},{"Start":"08:30.410 ","End":"08:34.985","Text":"makes them water insoluble despite their hydrophilicity,"},{"Start":"08:34.985 ","End":"08:38.915","Text":"despite them having tendency to bond and affiliate with water."},{"Start":"08:38.915 ","End":"08:41.645","Text":"Again, you see 2 units of a cellulose chain."},{"Start":"08:41.645 ","End":"08:46.130","Text":"The D-glucose residues are in the Beta-1,4 linkage."},{"Start":"08:46.130 ","End":"08:48.570","Text":"The rigid chair structures,"},{"Start":"08:48.570 ","End":"08:50.345","Text":"these are called stair structures,"},{"Start":"08:50.345 ","End":"08:52.955","Text":"can rotate relative to one another."},{"Start":"08:52.955 ","End":"08:55.220","Text":"There\u0027s the flexibility here because it is"},{"Start":"08:55.220 ","End":"08:59.050","Text":"just this bond that connects them so this can rotate."},{"Start":"08:59.050 ","End":"09:02.180","Text":"Now, here you see the scale drawing of segments of"},{"Start":"09:02.180 ","End":"09:05.660","Text":"2 parallel cellulose chains showing"},{"Start":"09:05.660 ","End":"09:09.530","Text":"the confirmation of the D-glucose residues and the hydrogen bond crossings."},{"Start":"09:09.530 ","End":"09:11.600","Text":"You see the hydrogen bonds that"},{"Start":"09:11.600 ","End":"09:18.135","Text":"cross-link these segments of the parallel cellulose chains."},{"Start":"09:18.135 ","End":"09:21.815","Text":"In the hexose unit at the lower left here,"},{"Start":"09:21.815 ","End":"09:23.570","Text":"all hydrogen atoms are shown."},{"Start":"09:23.570 ","End":"09:25.895","Text":"You see all of them, this is the white right,"},{"Start":"09:25.895 ","End":"09:27.973","Text":"to give you an illustration,"},{"Start":"09:27.973 ","End":"09:30.422","Text":"all the hydrogen atoms are shown."},{"Start":"09:30.422 ","End":"09:33.140","Text":"Whereas in the other hexose units,"},{"Start":"09:33.140 ","End":"09:34.565","Text":"the other 3,"},{"Start":"09:34.565 ","End":"09:37.790","Text":"the hydrogen attached to carbon have been omitted just for clarity,"},{"Start":"09:37.790 ","End":"09:40.569","Text":"and they do not participate in hydrogen bonding,"},{"Start":"09:40.569 ","End":"09:43.550","Text":"therefore, they are eliminated just to make it easier."},{"Start":"09:43.550 ","End":"09:44.825","Text":"But here you see all of them."},{"Start":"09:44.825 ","End":"09:47.750","Text":"It\u0027s not that here they don\u0027t exist, they exist,"},{"Start":"09:47.750 ","End":"09:51.215","Text":"they just were eliminated from the figure for clarity."},{"Start":"09:51.215 ","End":"09:55.175","Text":"Now, there\u0027s very important difference and cellulose"},{"Start":"09:55.175 ","End":"09:59.060","Text":"is that the glucose residues have the Beta configuration,"},{"Start":"09:59.060 ","End":"10:01.720","Text":"which we just explained."},{"Start":"10:01.720 ","End":"10:03.965","Text":"Now, as for the stacked structures,"},{"Start":"10:03.965 ","End":"10:06.620","Text":"we\u0027ll talk about that further and you will be able"},{"Start":"10:06.620 ","End":"10:09.770","Text":"to visualize it with figures that we have."},{"Start":"10:09.770 ","End":"10:13.220","Text":"With this, we completed part 1 of homopolysaccharides that"},{"Start":"10:13.220 ","End":"10:18.080","Text":"are for structure and we talked about cellulose,"},{"Start":"10:18.080 ","End":"10:22.400","Text":"cellulose structure, and the characteristics of cellulose."},{"Start":"10:22.400 ","End":"10:28.410","Text":"From here we\u0027re going to move on to another structural homopolysaccharide in part 2."}],"ID":30512},{"Watched":false,"Name":"Homopolysaccharides - Structure Part 2","Duration":"7m 19s","ChapterTopicVideoID":28964,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.035","Text":"Welcome back to Homopolysaccharides for Structure Part 2."},{"Start":"00:04.035 ","End":"00:06.750","Text":"In this part, we will continue to talk about"},{"Start":"00:06.750 ","End":"00:12.540","Text":"cellulose and specifically cellulose as fuel."},{"Start":"00:12.540 ","End":"00:14.130","Text":"We are talking about"},{"Start":"00:14.130 ","End":"00:18.675","Text":"structural polysaccharides and cellulose is a structural polysaccharide,"},{"Start":"00:18.675 ","End":"00:26.265","Text":"but we are going to touch up on its role that can be one for energy as fuel."},{"Start":"00:26.265 ","End":"00:29.505","Text":"We will then talk about cellulase."},{"Start":"00:29.505 ","End":"00:32.175","Text":"Summarizing and restating this,"},{"Start":"00:32.175 ","End":"00:35.270","Text":"cellulose provides plants with a rigid cell wall"},{"Start":"00:35.270 ","End":"00:40.160","Text":"consisting of hydrogen bonded cellulose fibrils."},{"Start":"00:40.160 ","End":"00:42.230","Text":"You see here microfibrils,"},{"Start":"00:42.230 ","End":"00:45.040","Text":"the small ones or the chain of cellulose molecules."},{"Start":"00:45.040 ","End":"00:49.220","Text":"When a lot of them come together to one they are the macro fibrils,"},{"Start":"00:49.220 ","End":"00:51.695","Text":"micro is small, macro is big."},{"Start":"00:51.695 ","End":"00:56.010","Text":"Like microbiology, macrobiology, microeconomics, macroeconomics."},{"Start":"00:56.010 ","End":"01:04.290","Text":"These bonded cellulose fibrils are held together by hemicellulose and pectin polymers."},{"Start":"01:04.290 ","End":"01:10.565","Text":"These are held together by hemicellulose and pectin polymers. What are these?"},{"Start":"01:10.565 ","End":"01:13.490","Text":"You have the hemicellulose and pectin polymers,"},{"Start":"01:13.490 ","End":"01:18.304","Text":"but hold these hydrogen bond and cellulose fibrils together."},{"Start":"01:18.304 ","End":"01:20.810","Text":"We have hemicellulose, which is"},{"Start":"01:20.810 ","End":"01:26.365","Text":"a branch heteropolymer containing up to 6 different sugars."},{"Start":"01:26.365 ","End":"01:32.945","Text":"Branched heteropolymer, meaning it is not of the same units."},{"Start":"01:32.945 ","End":"01:37.820","Text":"It is made of up to 6 different sugars and it is branch."},{"Start":"01:37.820 ","End":"01:39.380","Text":"You see here hemicellulose,"},{"Start":"01:39.380 ","End":"01:41.330","Text":"you see one structure of a sugar and"},{"Start":"01:41.330 ","End":"01:46.130","Text":"a different structured sugar here and you see that it\u0027s branched."},{"Start":"01:46.130 ","End":"01:47.360","Text":"It\u0027s not just linear,"},{"Start":"01:47.360 ","End":"01:49.400","Text":"but it has branches."},{"Start":"01:49.400 ","End":"01:54.655","Text":"Whereas pectin is a homopolymer of galacturonic acid."},{"Start":"01:54.655 ","End":"01:57.615","Text":"What we see here is pectin."},{"Start":"01:57.615 ","End":"02:00.105","Text":"It\u0027s the same unit,"},{"Start":"02:00.105 ","End":"02:05.375","Text":"the galacturonic acid the same monomer that repeats and makes the polymer."},{"Start":"02:05.375 ","End":"02:11.910","Text":"This is pectin and you see it doesn\u0027t have branches."},{"Start":"02:11.910 ","End":"02:18.080","Text":"You have hemicellulose and you have pectin it as a heteropolymer because it has"},{"Start":"02:18.080 ","End":"02:22.070","Text":"different types of sugars and you have"},{"Start":"02:22.070 ","End":"02:26.912","Text":"pectin as being a homopolymer because each unit is the same,"},{"Start":"02:26.912 ","End":"02:29.285","Text":"it is galacturonic acid."},{"Start":"02:29.285 ","End":"02:32.060","Text":"This one is branched you have the linear chain,"},{"Start":"02:32.060 ","End":"02:34.190","Text":"but there are branches to it."},{"Start":"02:34.190 ","End":"02:35.660","Text":"Therefore, it\u0027s not linear."},{"Start":"02:35.660 ","End":"02:38.165","Text":"You have the chain with branches,"},{"Start":"02:38.165 ","End":"02:43.470","Text":"whereas here you just have the linear chain of pectin."},{"Start":"02:43.470 ","End":"02:46.590","Text":"When you look at the cell wall the structure,"},{"Start":"02:46.590 ","End":"02:51.500","Text":"you have hemicellulose which are these thicker fibers,"},{"Start":"02:51.500 ","End":"02:56.570","Text":"and then you have pectin these thinner fibers and all of these come together."},{"Start":"02:56.570 ","End":"02:59.465","Text":"Whereas here you have the cellulose microfibrils."},{"Start":"02:59.465 ","End":"03:05.840","Text":"These are all held together by the hemicellulose and pectin polymers."},{"Start":"03:05.840 ","End":"03:10.300","Text":"Although cellulose consists entirely of glucose,"},{"Start":"03:10.300 ","End":"03:13.085","Text":"which is a useful form of metabolic energy,"},{"Start":"03:13.085 ","End":"03:17.105","Text":"most animals cannot use cellulose as a fuel source."},{"Start":"03:17.105 ","End":"03:19.790","Text":"Why is this? Well, it\u0027s because they lack the enzymes"},{"Start":"03:19.790 ","End":"03:23.600","Text":"cellulase to hydrolyze the Beta-1,4 linkages."},{"Start":"03:23.600 ","End":"03:25.820","Text":"These are linked differently."},{"Start":"03:25.820 ","End":"03:31.145","Text":"Remember we have in starch and whatnot Alpha 1,4 linkages,"},{"Start":"03:31.145 ","End":"03:35.525","Text":"whereas here in cellulose we have Beta-1,4 linkages."},{"Start":"03:35.525 ","End":"03:39.270","Text":"So these are different types of bonds and to be"},{"Start":"03:39.270 ","End":"03:44.555","Text":"broken a different enzyme is required, cellulase."},{"Start":"03:44.555 ","End":"03:49.880","Text":"So specifically vertebrate while glycogen and starch ingested in the diet are hydrolyzed"},{"Start":"03:49.880 ","End":"03:55.635","Text":"by amylases enzymes that can break these bonds."},{"Start":"03:55.635 ","End":"03:57.250","Text":"These are present in"},{"Start":"03:57.250 ","End":"03:59.920","Text":"saliva and intestinal secretions that"},{"Start":"03:59.920 ","End":"04:02.995","Text":"break these Alpha-1,4 glycosidic bonds between glucose units,"},{"Start":"04:02.995 ","End":"04:07.360","Text":"they lack cellulase that can break the Beta-1,4 linkages that are"},{"Start":"04:07.360 ","End":"04:11.950","Text":"found in cellulose in order to utilize the glucose."},{"Start":"04:11.950 ","End":"04:18.280","Text":"Yet herbivores have a symbiotic organisms in their digestive track that"},{"Start":"04:18.280 ","End":"04:21.790","Text":"secrete a series of enzymes collectively"},{"Start":"04:21.790 ","End":"04:26.200","Text":"known as cellulases which can break down cellulose."},{"Start":"04:26.200 ","End":"04:30.840","Text":"So herbivores that eat greens,"},{"Start":"04:30.840 ","End":"04:32.759","Text":"grass, and leaves,"},{"Start":"04:32.759 ","End":"04:38.015","Text":"they have this organism that lives in symbiosis with them,"},{"Start":"04:38.015 ","End":"04:44.390","Text":"that lives inside of them in a mutual beneficial relationship and these are in"},{"Start":"04:44.390 ","End":"04:48.080","Text":"their digestive track and secrete cellulase"},{"Start":"04:48.080 ","End":"04:51.950","Text":"is the enzymes that can break this Beta-1,4 linkage."},{"Start":"04:51.950 ","End":"04:55.490","Text":"The enzyme cellulose hydrolyze the beta-1,4 linkage,"},{"Start":"04:55.490 ","End":"05:02.495","Text":"and therefore the glucose that makes up cellulose can be utilized for energy."},{"Start":"05:02.495 ","End":"05:04.700","Text":"So this is what happens in herbivores,"},{"Start":"05:04.700 ","End":"05:06.890","Text":"zebras write things that are hoofed."},{"Start":"05:06.890 ","End":"05:10.160","Text":"What is another thing that we know that feeds on"},{"Start":"05:10.160 ","End":"05:14.235","Text":"plants and the case of wood, well termites."},{"Start":"05:14.235 ","End":"05:18.140","Text":"Termites readily digest cellulose and therefore would,"},{"Start":"05:18.140 ","End":"05:21.725","Text":"but only because their intestinal track harbors"},{"Start":"05:21.725 ","End":"05:30.830","Text":"a symbiotic microorganism called trichonympha that secretes cellulase as well."},{"Start":"05:30.830 ","End":"05:36.380","Text":"It hydrolyzes the Beta-1,4 linkages for the termites that then can"},{"Start":"05:36.380 ","End":"05:42.560","Text":"utilize the wood for the glucose units in it for energy."},{"Start":"05:42.560 ","End":"05:46.085","Text":"Again, you have an example of termites that have"},{"Start":"05:46.085 ","End":"05:49.880","Text":"a symbiotic microorganisms living within them"},{"Start":"05:49.880 ","End":"05:54.610","Text":"that secretes this enzyme and allows to utilize wood."},{"Start":"05:54.610 ","End":"06:00.140","Text":"Wood-rot fungi, meaning fungus that can grow on wood,"},{"Start":"06:00.140 ","End":"06:04.350","Text":"and bacteria also produce cellulase."},{"Start":"06:04.350 ","End":"06:10.580","Text":"As you see fungi like mushrooms can produce otherwise,"},{"Start":"06:10.580 ","End":"06:14.320","Text":"which is why they can actually grow on"},{"Start":"06:14.320 ","End":"06:19.670","Text":"tree trunks even wood that has rotted that\u0027s no longer alive."},{"Start":"06:19.670 ","End":"06:22.700","Text":"They can utilize the wood,"},{"Start":"06:22.700 ","End":"06:25.820","Text":"break it down in order to grow."},{"Start":"06:25.820 ","End":"06:29.150","Text":"The degradation of cellulose is a slow process because"},{"Start":"06:29.150 ","End":"06:32.840","Text":"it\u0027s tightly packed and hydrogen bonded glycan chains are"},{"Start":"06:32.840 ","End":"06:36.080","Text":"not easily accessible to cellulase and do not"},{"Start":"06:36.080 ","End":"06:40.055","Text":"separate readily even after many other glycosidic bonds have been hydrolyzed."},{"Start":"06:40.055 ","End":"06:43.520","Text":"Thus, cows and other ruminants must chew their cud"},{"Start":"06:43.520 ","End":"06:47.480","Text":"and we know them as to chew a lot and then it\u0027s processed and then"},{"Start":"06:47.480 ","End":"06:52.115","Text":"comes back to it some more and that has to do with"},{"Start":"06:52.115 ","End":"06:55.670","Text":"this tightly packed hydrogen bond and"},{"Start":"06:55.670 ","End":"07:01.545","Text":"polysaccharide glycogen that is held together very securely."},{"Start":"07:01.545 ","End":"07:05.510","Text":"With this we completed Part 2 of homopolysaccharides at play"},{"Start":"07:05.510 ","End":"07:11.465","Text":"a structural role and we learned in this section specifically about cellulose,"},{"Start":"07:11.465 ","End":"07:14.674","Text":"a structural homo polysaccharides as fuel,"},{"Start":"07:14.674 ","End":"07:19.680","Text":"as a source of energy and other cellulase the enzyme."}],"ID":30513},{"Watched":false,"Name":"Homopolysaccharides - Structure Part 3","Duration":"5m 54s","ChapterTopicVideoID":28965,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.865","Text":"Welcome back to homopolysaccharides for structural function Part 3."},{"Start":"00:05.865 ","End":"00:07.905","Text":"In this section you will learn about in"},{"Start":"00:07.905 ","End":"00:12.915","Text":"additional structural homopolysaccharide called chitin,"},{"Start":"00:12.915 ","End":"00:15.094","Text":"depending on where you\u0027re at,"},{"Start":"00:15.094 ","End":"00:19.800","Text":"chitin Structure and chitin characteristics."},{"Start":"00:19.800 ","End":"00:24.450","Text":"As we\u0027re talking about some homopolysaccharides that serve structural roles,"},{"Start":"00:24.450 ","End":"00:25.590","Text":"we\u0027re moving onto chitin,"},{"Start":"00:25.590 ","End":"00:32.535","Text":"which is a linear homopolysaccharide composed of N-acetylglucosamine residues in linkage."},{"Start":"00:32.535 ","End":"00:37.125","Text":"So you have N-acetylglucosamine residues."},{"Start":"00:37.125 ","End":"00:40.895","Text":"These are the same unit."},{"Start":"00:40.895 ","End":"00:42.905","Text":"These are linked to each other."},{"Start":"00:42.905 ","End":"00:48.305","Text":"If you have the chair form or the other form of showing this illustration,"},{"Start":"00:48.305 ","End":"00:52.412","Text":"it\u0027s the same molecule and a different presentation,"},{"Start":"00:52.412 ","End":"00:54.385","Text":"these are the repeating units."},{"Start":"00:54.385 ","End":"00:57.530","Text":"This is the N-acetylglucosamine residue,"},{"Start":"00:57.530 ","End":"01:03.145","Text":"and N stands for however many units there are that make up the chain."},{"Start":"01:03.145 ","End":"01:08.420","Text":"Now, the only chemical difference from cellulose is the replacement of"},{"Start":"01:08.420 ","End":"01:14.960","Text":"the hydroxyl group at C-2 with an acetylated amino group."},{"Start":"01:14.960 ","End":"01:18.110","Text":"You have carbon 1, carbon 2."},{"Start":"01:18.110 ","End":"01:22.520","Text":"This right here has been replaced the hydroxyl group,"},{"Start":"01:22.520 ","End":"01:29.675","Text":"the OH has been replaced with an amino group an acetylated amino group."},{"Start":"01:29.675 ","End":"01:36.820","Text":"Acetylated, meaning that it has the CH_3 here and amino group NH."},{"Start":"01:39.560 ","End":"01:42.830","Text":"Chitin is made of this unit repeating"},{"Start":"01:42.830 ","End":"01:47.030","Text":"N times and it is different from cellulose in the fact that at the C-2,"},{"Start":"01:47.030 ","End":"01:51.565","Text":"the second carbon of the ring structure or of the structure you have here."},{"Start":"01:51.565 ","End":"01:54.530","Text":"This is ring or here, this is the ring."},{"Start":"01:54.530 ","End":"02:00.200","Text":"You have acetylated amino group instead of the hydroxyl group."},{"Start":"02:00.200 ","End":"02:06.260","Text":"Chitin forms extended fibers similar to those of cellulose and like cellulose,"},{"Start":"02:06.260 ","End":"02:09.080","Text":"cannot be digested by vertebrates."},{"Start":"02:09.080 ","End":"02:14.900","Text":"Chitin is the main component of the structural component of invertebrate"},{"Start":"02:14.900 ","End":"02:21.170","Text":"hard exoskeletons of nearly a million species of arthropods,"},{"Start":"02:21.170 ","End":"02:24.290","Text":"insects and crustaceans, lobsters and crabs,"},{"Start":"02:24.290 ","End":"02:26.000","Text":"for example, spiders, etc."},{"Start":"02:26.000 ","End":"02:33.935","Text":"So all these have this hard outer shell and this is actually made of chitin."},{"Start":"02:33.935 ","End":"02:37.069","Text":"I use this example generally,"},{"Start":"02:37.069 ","End":"02:40.310","Text":"you know this from cockroaches and beetles and whatnot."},{"Start":"02:40.310 ","End":"02:44.645","Text":"I just like ladybugs better separate for this figure."},{"Start":"02:44.645 ","End":"02:50.390","Text":"It is also a component of the cell walls in most types of fungi,"},{"Start":"02:50.390 ","End":"02:55.925","Text":"remember mushrooms and many algae that we find in the seat."},{"Start":"02:55.925 ","End":"02:59.120","Text":"Considering it is in insects,"},{"Start":"02:59.120 ","End":"03:02.825","Text":"crustaceans, most fungi, and algae."},{"Start":"03:02.825 ","End":"03:05.930","Text":"The ocean is filled with algae."},{"Start":"03:05.930 ","End":"03:11.900","Text":"Then it is likely the second most abundant polysaccharide in nature."},{"Start":"03:11.900 ","End":"03:16.390","Text":"Remember, we talked about what\u0027s the most abundant in the biosphere."},{"Start":"03:16.390 ","End":"03:23.435","Text":"Having over 50 percent of the carbohydrates and the biosphere being cellulose."},{"Start":"03:23.435 ","End":"03:26.630","Text":"Well, chitin is considered to be"},{"Start":"03:26.630 ","End":"03:32.060","Text":"likely the second most abundant polysaccharide in nature."},{"Start":"03:32.060 ","End":"03:34.429","Text":"We are talking about homo polysaccharides,"},{"Start":"03:34.429 ","End":"03:35.630","Text":"that sort of structural roles."},{"Start":"03:35.630 ","End":"03:38.360","Text":"We\u0027re specifically talking about chitin is"},{"Start":"03:38.360 ","End":"03:42.700","Text":"the main component of exoskeletons and algae and fungi."},{"Start":"03:42.700 ","End":"03:48.575","Text":"Chitin like cellulose provides the organism with an excellent biomaterial for building"},{"Start":"03:48.575 ","End":"03:51.440","Text":"a strong body frame By virtue of"},{"Start":"03:51.440 ","End":"03:56.900","Text":"hydrogen bonding contacts within and between polysaccharide strands."},{"Start":"03:56.900 ","End":"04:00.140","Text":"Once again, we have this hydrogen bonding just like in cellulose,"},{"Start":"04:00.140 ","End":"04:07.745","Text":"that makes it organized and strongly bound and give the strong structure."},{"Start":"04:07.745 ","End":"04:15.795","Text":"Moreover, because the Beta-1,4 glycosidic bonds that are in this as are in cellulose."},{"Start":"04:15.795 ","End":"04:21.552","Text":"Just to show you, you have 1,"},{"Start":"04:21.552 ","End":"04:23.980","Text":"2, 3, 4, 1, 2, 3, 4."},{"Start":"04:23.980 ","End":"04:27.130","Text":"Again, you have the bond between 1,4."},{"Start":"04:27.130 ","End":"04:30.120","Text":"Beta-1,4 glycosidic bonds."},{"Start":"04:30.120 ","End":"04:34.430","Text":"Because of these Beta-1,4 glycosidic bonds,"},{"Start":"04:34.430 ","End":"04:37.430","Text":"chitin can be used as a source of"},{"Start":"04:37.430 ","End":"04:43.165","Text":"carbohydrate fuel by microorganisms that contain the enzyme chitinase."},{"Start":"04:43.165 ","End":"04:48.950","Text":"Meaning it needs an enzyme that can specifically break these bonds,"},{"Start":"04:48.950 ","End":"04:53.390","Text":"just as we said with cellulose that is broken down by"},{"Start":"04:53.390 ","End":"05:00.680","Text":"cellulase enzyme, suffix for enzyme."},{"Start":"05:00.680 ","End":"05:06.875","Text":"Here, chitin is broken down by chitinase."},{"Start":"05:06.875 ","End":"05:14.450","Text":"X-ray analysis indicates that chitin and cellulose have similar structures."},{"Start":"05:14.450 ","End":"05:22.520","Text":"So these in nature have resulted in similar structures and provide a similar role,"},{"Start":"05:22.520 ","End":"05:26.785","Text":"a similar function, they are structural."},{"Start":"05:26.785 ","End":"05:29.690","Text":"With this, we completed the topic of"},{"Start":"05:29.690 ","End":"05:36.170","Text":"homopolysaccharides for structural function within the topic of polysaccharides."},{"Start":"05:36.170 ","End":"05:39.800","Text":"In this section, we learned about the types of structural polysaccharides,"},{"Start":"05:39.800 ","End":"05:41.830","Text":"chitin and cellulose,"},{"Start":"05:41.830 ","End":"05:45.125","Text":"and the characteristics of such polysaccharides."},{"Start":"05:45.125 ","End":"05:50.210","Text":"We also mentioned which organisms can utilize them for energy,"},{"Start":"05:50.210 ","End":"05:54.600","Text":"for fuel, and what enables this to occur?"}],"ID":30514},{"Watched":false,"Name":"Exercise 9","Duration":"1m 51s","ChapterTopicVideoID":28966,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.393","Text":"Now that we\u0027ve covered homopolysaccharides that have structural function,"},{"Start":"00:05.393 ","End":"00:07.590","Text":"let\u0027s test our knowledge."},{"Start":"00:07.590 ","End":"00:11.100","Text":"Name the types of structural polysaccharides mentioned in"},{"Start":"00:11.100 ","End":"00:14.565","Text":"the lesson and in what organisms are they found?"},{"Start":"00:14.565 ","End":"00:16.260","Text":"Well, we mentioned 2,"},{"Start":"00:16.260 ","End":"00:19.140","Text":"we mentioned chitin and cellulose."},{"Start":"00:19.140 ","End":"00:21.630","Text":"Cellulose is a fibrous,"},{"Start":"00:21.630 ","End":"00:28.095","Text":"tough substance and it is found as the core component in the cell wall of plants."},{"Start":"00:28.095 ","End":"00:32.325","Text":"Cellulose is found in plants."},{"Start":"00:32.325 ","End":"00:35.120","Text":"My leaf, chitin on the other hand,"},{"Start":"00:35.120 ","End":"00:39.980","Text":"forms extended fibers similar to those as cellulose and is the main component of"},{"Start":"00:39.980 ","End":"00:45.790","Text":"invertebrate exoskeletons of arthropods, insects, and crustaceans."},{"Start":"00:45.790 ","End":"00:52.685","Text":"This means they are hard exoskeletons that are found in nearly a million species of"},{"Start":"00:52.685 ","End":"00:59.775","Text":"arthropods and this includes spiders and beetles and cucarachas,"},{"Start":"00:59.775 ","End":"01:03.724","Text":"cockroaches, lobsters, crabs, etc."},{"Start":"01:03.724 ","End":"01:10.570","Text":"It is also a component of the cell wall and most fungi and many algae."},{"Start":"01:10.570 ","End":"01:15.370","Text":"Chitin can be found in mushrooms,"},{"Start":"01:15.370 ","End":"01:17.405","Text":"like my little mushroom."},{"Start":"01:17.405 ","End":"01:26.880","Text":"Cellulose in plants, chitin in insects and crustaceans and fungi and algae."},{"Start":"01:26.880 ","End":"01:31.415","Text":"Remember we also talked about abundancy here."},{"Start":"01:31.415 ","End":"01:35.120","Text":"Try to think what we learned about abundancy and if you don\u0027t remember,"},{"Start":"01:35.120 ","End":"01:41.150","Text":"go back to the lesson because we said these are very abundant on earth,"},{"Start":"01:41.150 ","End":"01:45.515","Text":"with 1 being the most abundant carbohydrate and the"},{"Start":"01:45.515 ","End":"01:51.360","Text":"other most likely being the second most abundant carbohydrate."}],"ID":30515},{"Watched":false,"Name":"Exercise 10","Duration":"4m 8s","ChapterTopicVideoID":28967,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.590 ","End":"00:03.990","Text":"We\u0027re back with another exercise covering the lesson on"},{"Start":"00:03.990 ","End":"00:07.450","Text":"homopolysaccharides that function as structure."},{"Start":"00:07.700 ","End":"00:12.300","Text":"Which statement is false about cellulose?"},{"Start":"00:12.300 ","End":"00:17.085","Text":"A, it is a tough, fibrous water-insoluble substance."},{"Start":"00:17.085 ","End":"00:21.435","Text":"B, it is a core component in the cell wall of all plants."},{"Start":"00:21.435 ","End":"00:24.660","Text":"C, it can withstand great osmotic pressure differences"},{"Start":"00:24.660 ","End":"00:28.215","Text":"between the extracellular and intracellular spaces."},{"Start":"00:28.215 ","End":"00:32.385","Text":"D, it accounts for over half of the carbon in the biosphere."},{"Start":"00:32.385 ","End":"00:37.230","Text":"E, it is a linear, branched homo polysaccharide."},{"Start":"00:37.230 ","End":"00:40.150","Text":"Cellulose, function,"},{"Start":"00:40.150 ","End":"00:41.480","Text":"we talked about it."},{"Start":"00:41.480 ","End":"00:43.580","Text":"It has a tough,"},{"Start":"00:43.580 ","End":"00:49.790","Text":"fibrous structure and it is water insoluble."},{"Start":"00:49.790 ","End":"00:53.210","Text":"Otherwise, it wouldn\u0027t be able to hold"},{"Start":"00:53.210 ","End":"00:57.785","Text":"the water of the cells outside or inside or separate."},{"Start":"00:57.785 ","End":"00:59.150","Text":"This is true, therefore,"},{"Start":"00:59.150 ","End":"01:00.580","Text":"it\u0027s not our answer."},{"Start":"01:00.580 ","End":"01:02.985","Text":"We\u0027ve eliminated A. B,"},{"Start":"01:02.985 ","End":"01:06.530","Text":"it is a core component in a cell walls of all plants."},{"Start":"01:06.530 ","End":"01:13.570","Text":"Well, yes, it is the main glycan that makes up the cell wall of plants."},{"Start":"01:13.570 ","End":"01:17.505","Text":"It is that rigid, tough, fibrous component."},{"Start":"01:17.505 ","End":"01:19.700","Text":"This again is a true statement,"},{"Start":"01:19.700 ","End":"01:21.470","Text":"therefore, it\u0027s not our answer."},{"Start":"01:21.470 ","End":"01:24.290","Text":"Now, it can withstand great osmotic pressure differences"},{"Start":"01:24.290 ","End":"01:27.650","Text":"between the extracellular and intracellular spaces."},{"Start":"01:27.650 ","End":"01:31.220","Text":"Because of its strength in the bonds between it,"},{"Start":"01:31.220 ","End":"01:33.110","Text":"it can withstand osmotic pressure."},{"Start":"01:33.110 ","End":"01:35.675","Text":"We even mentioned 20 atmosphere."},{"Start":"01:35.675 ","End":"01:38.300","Text":"Remember, atmosphere is a measure of pressure,"},{"Start":"01:38.300 ","End":"01:43.190","Text":"and generally normal for us is 1 atmosphere."},{"Start":"01:43.190 ","End":"01:49.650","Text":"That\u0027s what we generally live within our surrounding and our environment,"},{"Start":"01:49.650 ","End":"01:51.860","Text":"so 20 is much greater."},{"Start":"01:51.860 ","End":"01:55.760","Text":"It can withstand this great osmotic pressure and this helps"},{"Start":"01:55.760 ","End":"02:02.825","Text":"maintain the cell structure because as you have the cell with a lot of components,"},{"Start":"02:02.825 ","End":"02:08.675","Text":"it can result if there are more components while the extracellular fluid is"},{"Start":"02:08.675 ","End":"02:15.295","Text":"with less water would enter and can result in the cell expanding and bursting."},{"Start":"02:15.295 ","End":"02:20.120","Text":"The cellulose helps withstand this pressure to that\u0027s doesn\u0027t occur and"},{"Start":"02:20.120 ","End":"02:24.230","Text":"it is important for plants to actually absorb water."},{"Start":"02:24.230 ","End":"02:31.455","Text":"This is important for photosynthesis and also release of water during its processes."},{"Start":"02:31.455 ","End":"02:33.170","Text":"This is a correct answer, therefore,"},{"Start":"02:33.170 ","End":"02:35.990","Text":"it\u0027s not our answer here."},{"Start":"02:35.990 ","End":"02:40.624","Text":"Next, D, it accounts for over half of the carbon on the biosphere."},{"Start":"02:40.624 ","End":"02:43.460","Text":"Well, actually, we said cellulose is"},{"Start":"02:43.460 ","End":"02:48.335","Text":"the most abundant carbohydrate in the biosphere and yes,"},{"Start":"02:48.335 ","End":"02:51.470","Text":"we set it accounts for over half of the carbon and the biosphere."},{"Start":"02:51.470 ","End":"02:54.260","Text":"Therefore, this is true and not our answer."},{"Start":"02:54.260 ","End":"02:57.335","Text":"Last but not least, we have E,"},{"Start":"02:57.335 ","End":"03:01.985","Text":"it is a linear branched homopolysaccharide so let\u0027s, think about it."},{"Start":"03:01.985 ","End":"03:07.685","Text":"Linear. Well, if you remember the chains and we said that they arrange and stack,"},{"Start":"03:07.685 ","End":"03:10.385","Text":"therefore they need to be linear."},{"Start":"03:10.385 ","End":"03:11.615","Text":"This is correct."},{"Start":"03:11.615 ","End":"03:15.860","Text":"We also have that it\u0027s branched and it\u0027s a homopolysaccharide."},{"Start":"03:15.860 ","End":"03:20.030","Text":"Well, this whole section is about homopolysaccharides,"},{"Start":"03:20.030 ","End":"03:22.670","Text":"but homopolysaccharides that have"},{"Start":"03:22.670 ","End":"03:26.360","Text":"the role and function so we know it\u0027s a homopolysaccharide."},{"Start":"03:26.360 ","End":"03:29.495","Text":"The one thing we\u0027re mentioning, it\u0027s branched,"},{"Start":"03:29.495 ","End":"03:35.945","Text":"where in essence you have a contradiction here because we\u0027re seeing linear and branched."},{"Start":"03:35.945 ","End":"03:44.615","Text":"I would say this is our incorrect statement because this would not be true therefore,"},{"Start":"03:44.615 ","End":"03:47.779","Text":"E is our correct answer."},{"Start":"03:47.779 ","End":"03:50.405","Text":"It is a linear-branched homopolysaccharide."},{"Start":"03:50.405 ","End":"03:53.450","Text":"What would be correct if we said"},{"Start":"03:53.450 ","End":"03:57.320","Text":"like amylose and the main chains of amylopectin and glycogen,"},{"Start":"03:57.320 ","End":"04:01.915","Text":"cellulose is a linear, unbranched homo polysaccharide."},{"Start":"04:01.915 ","End":"04:08.070","Text":"With that, we covered a few very important characteristics of cellulose."}],"ID":30516},{"Watched":false,"Name":"Exercise 11","Duration":"2m 18s","ChapterTopicVideoID":28968,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.625","Text":"You have another exercise on Homopolysaccharides that function as structure."},{"Start":"00:05.625 ","End":"00:08.160","Text":"Define the terms hemicellulose,"},{"Start":"00:08.160 ","End":"00:11.055","Text":"pectin, and cellulase."},{"Start":"00:11.055 ","End":"00:15.270","Text":"Cellulase consists of hydrogen-bonded Cellulose fibrils which"},{"Start":"00:15.270 ","End":"00:19.395","Text":"are held together by hemicellulose and pectin polymers."},{"Start":"00:19.395 ","End":"00:26.340","Text":"Hemicellulose is a branched heteropolymer containing up to 6 different sugars,"},{"Start":"00:26.340 ","End":"00:30.900","Text":"whereas pectin is a homopolymer of galacturonic acid."},{"Start":"00:30.900 ","End":"00:35.145","Text":"We see here hemicellulose and pectin,"},{"Start":"00:35.145 ","End":"00:40.740","Text":"hemicellulose has the different types of sugars,"},{"Start":"00:40.740 ","End":"00:43.920","Text":"you see in pectin it\u0027s exactly the same unit repeating,"},{"Start":"00:43.920 ","End":"00:47.925","Text":"it is linear and this one is branched,"},{"Start":"00:47.925 ","End":"00:50.785","Text":"so it has branches."},{"Start":"00:50.785 ","End":"00:56.510","Text":"You see here in the cell wall you have hemicellulose and pectin."},{"Start":"00:56.510 ","End":"01:02.050","Text":"These are what hold the hydrogen bonded cellulose fibrils together in cellulose."},{"Start":"01:02.050 ","End":"01:05.760","Text":"Now Cellulase, the suffix,"},{"Start":"01:05.760 ","End":"01:07.815","Text":"-ase, indicates enzyme."},{"Start":"01:07.815 ","End":"01:13.250","Text":"Cellulase is an enzyme that is able to hydrolyze the Beta-1,4 linkages,"},{"Start":"01:13.250 ","End":"01:17.180","Text":"meaning it can break the bonds that hold the cellulose units together."},{"Start":"01:17.180 ","End":"01:22.095","Text":"Remember Beta- 1,4 linkage is what links the units together,"},{"Start":"01:22.095 ","End":"01:24.135","Text":"and this is what is different,"},{"Start":"01:24.135 ","End":"01:27.500","Text":"than the homopolysaccharides that were"},{"Start":"01:27.500 ","End":"01:31.595","Text":"mentioned in the section on homopolysaccharides for fuel."},{"Start":"01:31.595 ","End":"01:39.070","Text":"These are different linkages and need different enzymes to break these down, cellulase."},{"Start":"01:39.070 ","End":"01:41.960","Text":"Now although cellulose consists entirely of glucose,"},{"Start":"01:41.960 ","End":"01:45.980","Text":"which is a useful form of metabolic energy as explained in a previous lesson,"},{"Start":"01:45.980 ","End":"01:52.115","Text":"most animals cannot use cellulose as a fuel source because they lack this enzyme,"},{"Start":"01:52.115 ","End":"01:59.810","Text":"so they can\u0027t break down the Beta-1,4 linkages because in glycogen or starch,"},{"Start":"01:59.810 ","End":"02:02.630","Text":"it is Alpha-1,4 linkages."},{"Start":"02:02.630 ","End":"02:08.140","Text":"These are different bonds and require different enzymes to break these down."},{"Start":"02:08.140 ","End":"02:11.265","Text":"Most animals cannot use cellulose as"},{"Start":"02:11.265 ","End":"02:15.390","Text":"a fuel source because they lack this enzyme cellulase,"},{"Start":"02:15.390 ","End":"02:19.030","Text":"and with that we\u0027ve completed this exercise."}],"ID":30517},{"Watched":false,"Name":"Exercise 12","Duration":"1m 54s","ChapterTopicVideoID":28969,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:03.480","Text":"Well, as we are building our confidence on"},{"Start":"00:03.480 ","End":"00:06.390","Text":"the knowledge on how a polysaccharides that form a structure,"},{"Start":"00:06.390 ","End":"00:10.005","Text":"let\u0027s test it furthermore."},{"Start":"00:10.005 ","End":"00:15.045","Text":"Define chitin and mentioned a number of its characteristics."},{"Start":"00:15.045 ","End":"00:17.130","Text":"This should be easy peasy."},{"Start":"00:17.130 ","End":"00:20.670","Text":"Chitin is a linear homopolysaccharide"},{"Start":"00:20.670 ","End":"00:24.645","Text":"composed of N-acetylglucosamine residues linked together."},{"Start":"00:24.645 ","End":"00:27.060","Text":"This part, linear homopolysaccharides,"},{"Start":"00:27.060 ","End":"00:29.290","Text":"should have been easy."},{"Start":"00:29.600 ","End":"00:35.760","Text":"This, you may have not remember exactly, but N-acetylglucosamine,"},{"Start":"00:35.760 ","End":"00:39.590","Text":"so think of glucose and remember the difference"},{"Start":"00:39.590 ","End":"00:43.745","Text":"between chitin and cellulose is that you have"},{"Start":"00:43.745 ","End":"00:46.955","Text":"a difference that a hydroxyl group"},{"Start":"00:46.955 ","End":"00:52.100","Text":"in one of the carbons has been replaced by an amine group."},{"Start":"00:52.100 ","End":"00:56.760","Text":"It\u0027s glucose with an amine group, so N-acetylglucosamine."},{"Start":"00:56.760 ","End":"00:59.825","Text":"Chitin is a linear homopolysaccharide composed"},{"Start":"00:59.825 ","End":"01:03.845","Text":"of N-acetylglucosamine residues linked together."},{"Start":"01:03.845 ","End":"01:07.940","Text":"Chitin. Let\u0027s talk about its characteristics."},{"Start":"01:07.940 ","End":"01:10.910","Text":"Chitin is the main structural component of invertebrate,"},{"Start":"01:10.910 ","End":"01:17.740","Text":"hard exoskeletons of nearly a million species of arthropods, insects, and crustaceans."},{"Start":"01:17.740 ","End":"01:20.640","Text":"We mentioned cockroaches,"},{"Start":"01:20.640 ","End":"01:24.060","Text":"we had ladybugs, lobsters, crabs."},{"Start":"01:24.060 ","End":"01:25.800","Text":"These are crustaceans,"},{"Start":"01:25.800 ","End":"01:26.895","Text":"the lobsters and crabs."},{"Start":"01:26.895 ","End":"01:32.465","Text":"It is also a component of the cell walls in most types of fungi and many types of algae."},{"Start":"01:32.465 ","End":"01:36.575","Text":"Fungi, these is different types of mushrooms, etc."},{"Start":"01:36.575 ","End":"01:42.890","Text":"This makes it likely to being the second most abundant polysaccharide in nature,"},{"Start":"01:42.890 ","End":"01:50.600","Text":"second to cellulose being the most abundant polysaccharide in the biosphere."},{"Start":"01:50.600 ","End":"01:53.580","Text":"There you have it, chitin."}],"ID":30518},{"Watched":false,"Name":"Exercise 13","Duration":"7m 5s","ChapterTopicVideoID":28970,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:02.235","Text":"Let\u0027s dive into another question,"},{"Start":"00:02.235 ","End":"00:05.400","Text":"testing our knowledge on homopolysaccharides full structure."},{"Start":"00:05.400 ","End":"00:08.880","Text":"Which statement refers to cellulose and which to chitin."},{"Start":"00:08.880 ","End":"00:14.580","Text":"1, it provides the organism with an excellent biomaterial for building a strong body"},{"Start":"00:14.580 ","End":"00:21.370","Text":"framed by virtue of hydrogen-bonding contacts within and between polysaccharide strands."},{"Start":"00:21.500 ","End":"00:26.525","Text":"This sounds like it almost can be for either one of them."},{"Start":"00:26.525 ","End":"00:27.740","Text":"Let\u0027s continue to read,"},{"Start":"00:27.740 ","End":"00:30.530","Text":"let this sink in and then we\u0027ll go again 1 by 1."},{"Start":"00:30.530 ","End":"00:32.285","Text":"2, it is a linear,"},{"Start":"00:32.285 ","End":"00:34.850","Text":"unbranched homopolysaccharide consisting of"},{"Start":"00:34.850 ","End":"00:40.200","Text":"nearly a thousand repeating units of a disaccharide called cellobiose."},{"Start":"00:40.200 ","End":"00:43.305","Text":"Cellobiose, where did we mention that?"},{"Start":"00:43.305 ","End":"00:48.260","Text":"3, herbivores and termites can utilize this as a form of fuel since they harbor"},{"Start":"00:48.260 ","End":"00:50.780","Text":"symbiotic organisms in their digestive tract"},{"Start":"00:50.780 ","End":"00:54.325","Text":"that secrete enzymes which can break it down."},{"Start":"00:54.325 ","End":"00:57.195","Text":"What do these eat?"},{"Start":"00:57.195 ","End":"01:03.065","Text":"4, it is a component of the cell walls in most types of fungi and many algae."},{"Start":"01:03.065 ","End":"01:06.100","Text":"We talked about mushroom and algae in the sea."},{"Start":"01:06.100 ","End":"01:10.945","Text":"5, it is the most abundant carbohydrate on earth."},{"Start":"01:10.945 ","End":"01:15.280","Text":"6, it is the second most abundant polysaccharide on earth."},{"Start":"01:15.280 ","End":"01:18.820","Text":"Well this one will be easy for us because once we know the one,"},{"Start":"01:18.820 ","End":"01:20.305","Text":"it will define the other."},{"Start":"01:20.305 ","End":"01:26.590","Text":"Let\u0027s go back to one. It provides the organism with an excellent biomaterial for building"},{"Start":"01:26.590 ","End":"01:29.230","Text":"a strong body frame by virtue of"},{"Start":"01:29.230 ","End":"01:34.650","Text":"hydrogen-bonding contacts within and between polysaccharide strands."},{"Start":"01:34.650 ","End":"01:40.795","Text":"Well, biomaterial for building a strong body frame."},{"Start":"01:40.795 ","End":"01:45.250","Text":"I would say this would be chitin because it builds"},{"Start":"01:45.250 ","End":"01:52.005","Text":"the exoskeleton of the organism, the body frame."},{"Start":"01:52.005 ","End":"01:54.630","Text":"First is with cellulose,"},{"Start":"01:54.630 ","End":"01:58.530","Text":"it builds a strong frame for the cell."},{"Start":"01:58.530 ","End":"02:01.475","Text":"A cellular structural frame."},{"Start":"02:01.475 ","End":"02:05.465","Text":"Chitin is the exoskeleton,"},{"Start":"02:05.465 ","End":"02:09.795","Text":"Cellulose is the cell wall."},{"Start":"02:09.795 ","End":"02:17.640","Text":"Chitin. 2, it is a linear, unbranched homopolysaccharides."},{"Start":"02:17.640 ","End":"02:22.570","Text":"We know that this refers to both"},{"Start":"02:22.570 ","End":"02:28.480","Text":"consisting of nearly a thousand repeating units of a disaccharide called cellobiose."},{"Start":"02:28.480 ","End":"02:32.150","Text":"Well, this is a little hint."},{"Start":"02:32.150 ","End":"02:39.340","Text":"Cellobiose, we mentioned this as the building block of"},{"Start":"02:39.340 ","End":"02:46.885","Text":"cellulose and this cello can be the hint to that."},{"Start":"02:46.885 ","End":"02:55.200","Text":"Remember with chitin, we said that it is a chain of a repeating units."},{"Start":"02:55.200 ","End":"03:03.165","Text":"The end glucosamine, it\u0027s the repeating unit of the same monosaccharide."},{"Start":"03:03.165 ","End":"03:07.810","Text":"It\u0027s a homopolysaccharide made of repeating unit."},{"Start":"03:07.810 ","End":"03:11.680","Text":"Whereas here, cellulose is a homopolysaccharide that"},{"Start":"03:11.680 ","End":"03:16.780","Text":"consists of repeating units of a disaccharide called cellobiose,"},{"Start":"03:16.780 ","End":"03:19.205","Text":"this one is cellulose."},{"Start":"03:19.205 ","End":"03:24.380","Text":"3, herbivorous and termites can utilize this as a form of fuels"},{"Start":"03:24.380 ","End":"03:26.330","Text":"since they have a symbiotic organisms in"},{"Start":"03:26.330 ","End":"03:29.540","Text":"their digestive tract that secrete enzymes which can break it down."},{"Start":"03:29.540 ","End":"03:32.060","Text":"What do herbivores and termites eat?"},{"Start":"03:32.060 ","End":"03:33.730","Text":"Termites eat wood."},{"Start":"03:33.730 ","End":"03:37.275","Text":"Herbivores: cows, zebras, giraffes,"},{"Start":"03:37.275 ","End":"03:41.775","Text":"they eat plants, grass, or whatnot."},{"Start":"03:41.775 ","End":"03:47.025","Text":"What did we say is what makes up plants."},{"Start":"03:47.025 ","End":"03:50.210","Text":"We said cellulose is the main component,"},{"Start":"03:50.210 ","End":"03:53.030","Text":"the core component of plant cell walls."},{"Start":"03:53.030 ","End":"03:56.725","Text":"Therefore it makes sense that we\u0027re talking about cellulose here."},{"Start":"03:56.725 ","End":"03:59.220","Text":"Now we mentioned that cellulose,"},{"Start":"03:59.220 ","End":"04:03.375","Text":"we are talking about homopolysaccharides that are used for structure."},{"Start":"04:03.375 ","End":"04:11.070","Text":"Both of these are structural homopolysaccharides."},{"Start":"04:11.070 ","End":"04:14.975","Text":"If there\u0027s structural, they were not described as"},{"Start":"04:14.975 ","End":"04:19.925","Text":"the fuel homopolysaccharides which we discussed in the previous lesson."},{"Start":"04:19.925 ","End":"04:23.270","Text":"Yet, therefore, most animals can\u0027t use this for fuel and"},{"Start":"04:23.270 ","End":"04:26.600","Text":"don\u0027t use it for fuel but these examples are"},{"Start":"04:26.600 ","End":"04:30.379","Text":"the exceptions where they can use it for fuel because"},{"Start":"04:30.379 ","End":"04:34.440","Text":"they have a symbiotic organism that lives within them in"},{"Start":"04:34.440 ","End":"04:38.010","Text":"their digestive tract and therefore they can"},{"Start":"04:38.010 ","End":"04:43.680","Text":"actually use cellulose break this down for fuel."},{"Start":"04:43.680 ","End":"04:46.819","Text":"Thank the Lord for that because that means it\u0027s separates"},{"Start":"04:46.819 ","End":"04:49.820","Text":"evolutionary wise what animals eat."},{"Start":"04:49.820 ","End":"04:52.100","Text":"We don\u0027t all eat the same thing,"},{"Start":"04:52.100 ","End":"04:58.605","Text":"so we don\u0027t all finish all the products of the same kind."},{"Start":"04:58.605 ","End":"05:01.410","Text":"Herbivorous and termites,"},{"Start":"05:01.410 ","End":"05:02.845","Text":"they eat plants and wood."},{"Start":"05:02.845 ","End":"05:07.430","Text":"Harbor a symbiotic organisms in their digestive tract that secrete enzymes which can"},{"Start":"05:07.430 ","End":"05:12.195","Text":"break it down the cellulose and this is the cellulase."},{"Start":"05:12.195 ","End":"05:13.695","Text":"Remember this enzyme?"},{"Start":"05:13.695 ","End":"05:17.285","Text":"These organisms secrete cellulase which allows"},{"Start":"05:17.285 ","End":"05:22.350","Text":"for the utilization and the breakdown of the Beta 1,"},{"Start":"05:22.350 ","End":"05:28.345","Text":"4 glycosidic bonds that are found in cellulose,"},{"Start":"05:28.345 ","End":"05:30.735","Text":"so this is cellulose."},{"Start":"05:30.735 ","End":"05:32.425","Text":"We are going to 4."},{"Start":"05:32.425 ","End":"05:37.910","Text":"It is a component of a cell walls in most types of fungi and many algae."},{"Start":"05:37.910 ","End":"05:43.864","Text":"We mentioned cellulose as being in cell walls of all plants,"},{"Start":"05:43.864 ","End":"05:48.110","Text":"yet for fungi and many algae,"},{"Start":"05:48.110 ","End":"05:56.435","Text":"we actually mentioned chitin as being the component of the cell walls."},{"Start":"05:56.435 ","End":"05:59.495","Text":"In this case we have chitin and because of"},{"Start":"05:59.495 ","End":"06:06.295","Text":"this and its presence in insects, it\u0027s very prevalent."},{"Start":"06:06.295 ","End":"06:09.700","Text":"We\u0027re going now to 5 and 6."},{"Start":"06:09.700 ","End":"06:13.540","Text":"Which one is the most abundant carbohydrate on"},{"Start":"06:13.540 ","End":"06:18.410","Text":"earth and which one is the second most abundant polysaccharide on earth?"},{"Start":"06:19.490 ","End":"06:24.970","Text":"Well, we mentioned that the most abundant carbohydrate on earth actually takes"},{"Start":"06:24.970 ","End":"06:30.055","Text":"up more than 50 percent of the cards in the biosphere on earth."},{"Start":"06:30.055 ","End":"06:36.460","Text":"We mentioned that as being cellulose whereas we said that chitin"},{"Start":"06:36.460 ","End":"06:39.640","Text":"most likely is the second most prevalent due to"},{"Start":"06:39.640 ","End":"06:43.300","Text":"being in all insects even though they\u0027re small but there are a lot of insects."},{"Start":"06:43.300 ","End":"06:45.650","Text":"Furthermore what yields and brings it"},{"Start":"06:45.650 ","End":"06:49.490","Text":"to being likely the second most abundant is because it\u0027s also"},{"Start":"06:49.490 ","End":"06:56.235","Text":"found in fungi and many types of algae that fills the ocean."},{"Start":"06:56.235 ","End":"06:59.270","Text":"The most abundant carbohydrate on earth is cellulose while"},{"Start":"06:59.270 ","End":"07:02.675","Text":"the second most abundant polysaccharide on earth is chitin."},{"Start":"07:02.675 ","End":"07:05.940","Text":"With that, we completed this exercise."}],"ID":30519},{"Watched":false,"Name":"Heteropolysaccharides - Structure Part 1","Duration":"13m 5s","ChapterTopicVideoID":28971,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:02.805","Text":"Welcome back. We\u0027re within polysaccharides and we"},{"Start":"00:02.805 ","End":"00:06.390","Text":"are now going to move into heteropolysaccharides."},{"Start":"00:06.390 ","End":"00:09.420","Text":"Whereas before we covered homopolysaccharides,"},{"Start":"00:09.420 ","End":"00:14.700","Text":"we talked about homo polysaccharides that serve the function of fuel or structure."},{"Start":"00:14.700 ","End":"00:16.680","Text":"Now we\u0027re going to talk about the type of"},{"Start":"00:16.680 ","End":"00:19.050","Text":"polysaccharides that are heteropolysaccharides,"},{"Start":"00:19.050 ","End":"00:21.690","Text":"meaning different units that build up the chain of"},{"Start":"00:21.690 ","End":"00:27.060","Text":"the polysaccharide that function as structural roles."},{"Start":"00:27.060 ","End":"00:29.100","Text":"Now in this section we will learn about the type of"},{"Start":"00:29.100 ","End":"00:33.720","Text":"structural hetero polysaccharides and the characteristics of such polysaccharides."},{"Start":"00:33.720 ","End":"00:36.780","Text":"We\u0027ll split this lesson into 2 parts,"},{"Start":"00:36.780 ","End":"00:41.390","Text":"and in this part we are going to introduce and learn about types of"},{"Start":"00:41.390 ","End":"00:46.205","Text":"structural heteropolysaccharides and the structure of such polysaccharides."},{"Start":"00:46.205 ","End":"00:51.440","Text":"We are talking about cell walls that contain heteropolysaccharides."},{"Start":"00:51.440 ","End":"00:54.440","Text":"Remember we have homopolysaccharides and heteropolysaccharides."},{"Start":"00:54.440 ","End":"01:00.545","Text":"Homopolysaccharides have the same units and we are now moving on to heteropolysaccharides"},{"Start":"01:00.545 ","End":"01:06.980","Text":"that have different units that compose the polysaccharides,"},{"Start":"01:06.980 ","End":"01:09.890","Text":"different sugar molecules that make it"},{"Start":"01:09.890 ","End":"01:13.415","Text":"up and it can be unbranched or linear chain or branched."},{"Start":"01:13.415 ","End":"01:18.340","Text":"The rigid component of bacterial cell walls is a heteropolymorph alternating Beta-1,"},{"Start":"01:18.340 ","End":"01:24.485","Text":"4-linked N-acetylglucosamine and N-acetylmuramic acid residues."},{"Start":"01:24.485 ","End":"01:26.825","Text":"Remember we talked about in chitin,"},{"Start":"01:26.825 ","End":"01:29.100","Text":"we had Beta-1,"},{"Start":"01:29.100 ","End":"01:35.825","Text":"4-linked N-acetylglucosamine entirely made of N-acetylglucosamine."},{"Start":"01:35.825 ","End":"01:40.960","Text":"Chitin has these, just like cellulose also is Beta-1,"},{"Start":"01:40.960 ","End":"01:43.100","Text":"4-linked, but it is made of glucose,"},{"Start":"01:43.100 ","End":"01:45.650","Text":"whereas chitin is made of acetyl glucosamin."},{"Start":"01:45.650 ","End":"01:53.915","Text":"Whereas the glucose had a carbon replace the hydroxyl group with an amine group."},{"Start":"01:53.915 ","End":"01:58.505","Text":"We\u0027re talking about the bacterial cell wall,"},{"Start":"01:58.505 ","End":"02:04.780","Text":"which is made of alternating linked units by Beta-1,"},{"Start":"02:04.780 ","End":"02:09.080","Text":"4 of these 2 different molecules."},{"Start":"02:09.080 ","End":"02:14.720","Text":"You have N-acetylglucosamine and N-acetylmuramic acid residues alternating."},{"Start":"02:14.720 ","End":"02:22.255","Text":"You have G for glucosamine, M for muramic."},{"Start":"02:22.255 ","End":"02:26.495","Text":"This is just to make it easy to see the structure, to visualize it."},{"Start":"02:26.495 ","End":"02:29.060","Text":"This is the legend."},{"Start":"02:29.060 ","End":"02:31.870","Text":"You have alternating units."},{"Start":"02:31.870 ","End":"02:37.885","Text":"You have muramic acid and glucose amine alternating."},{"Start":"02:37.885 ","End":"02:42.275","Text":"This is a chain where it alternates and they\u0027re stacked."},{"Start":"02:42.275 ","End":"02:46.795","Text":"How cellulose can stop organized with different bonds."},{"Start":"02:46.795 ","End":"02:51.985","Text":"What combines them is the Beta-1,4 between the M and the G,"},{"Start":"02:51.985 ","End":"02:55.255","Text":"the glucosamine and the muramic acid."},{"Start":"02:55.255 ","End":"03:00.100","Text":"Furthermore between them we talked about in cellulose and chitin,"},{"Start":"03:00.100 ","End":"03:04.577","Text":"the hydrogen bonds and so does the Van der Waals interactions,"},{"Start":"03:04.577 ","End":"03:06.550","Text":"so you also see bonds here."},{"Start":"03:06.550 ","End":"03:15.370","Text":"You have cross bridges between the different chains,"},{"Start":"03:15.370 ","End":"03:17.125","Text":"so you have a peptide link."},{"Start":"03:17.125 ","End":"03:23.245","Text":"You see pentaglycine cross-bridge and a pentapeptide association as well,"},{"Start":"03:23.245 ","End":"03:24.910","Text":"that\u0027s in the yellow and pink."},{"Start":"03:24.910 ","End":"03:28.180","Text":"You see these peptide chains at the ends,"},{"Start":"03:28.180 ","End":"03:33.745","Text":"yellow that are linked by this pentaglycine cross-bridge."},{"Start":"03:33.745 ","End":"03:36.800","Text":"You have glycinespenta."},{"Start":"03:37.730 ","End":"03:42.925","Text":"This pentaglycine means there are 5 right penta like a pentagon."},{"Start":"03:42.925 ","End":"03:50.450","Text":"5 sides or 5 glycines, 1,2,3,4,5,"},{"Start":"03:50.450 ","End":"03:56.860","Text":"that connect the link is pentapeptide,"},{"Start":"03:56.860 ","End":"04:01.355","Text":"chains made of 5 peptides and adenine,"},{"Start":"04:01.355 ","End":"04:04.910","Text":"leucine and lysine and alanine and the last alanine is"},{"Start":"04:04.910 ","End":"04:09.395","Text":"removed when the pentaglycine links them together."},{"Start":"04:09.395 ","End":"04:18.475","Text":"This is the peptidoglycan structure of bacteria, specifically Gram positive."},{"Start":"04:18.475 ","End":"04:21.830","Text":"This is not a microbiology class and"},{"Start":"04:21.830 ","End":"04:24.890","Text":"we\u0027re not covering this not even in this facility, a biology class."},{"Start":"04:24.890 ","End":"04:30.050","Text":"I\u0027m not covering the differences between Gram positive and Gram negative bacteria."},{"Start":"04:30.050 ","End":"04:37.100","Text":"I will just broadly say it is in the structure of the membrane and cell wall."},{"Start":"04:37.100 ","End":"04:39.514","Text":"In this case you see Gram positive."},{"Start":"04:39.514 ","End":"04:45.320","Text":"You have the alternating residues that are"},{"Start":"04:45.320 ","End":"04:52.100","Text":"linked together with peptides that are linked with a pentaglycine cross-bridge."},{"Start":"04:52.100 ","End":"04:54.815","Text":"Basically there\u0027s a bridge, they\u0027re linked together."},{"Start":"04:54.815 ","End":"05:00.005","Text":"What you see here is Gram positive bacteria Staphylococcus Aureus as an example."},{"Start":"05:00.005 ","End":"05:04.349","Text":"You see that there\u0027s the cytoplasmic membrane, phospholipid membrane."},{"Start":"05:04.349 ","End":"05:05.633","Text":"We covered this in previous lessons,"},{"Start":"05:05.633 ","End":"05:07.040","Text":"this should be easy and clear."},{"Start":"05:07.040 ","End":"05:09.575","Text":"Then you have the peptidoglycan."},{"Start":"05:09.575 ","End":"05:14.675","Text":"This is the heteropolysaccharide"},{"Start":"05:14.675 ","End":"05:21.290","Text":"that forms the structure of the cell wall of a bacteria and algae."},{"Start":"05:21.290 ","End":"05:27.575","Text":"This peptidoglycan is made up of these chains."},{"Start":"05:27.575 ","End":"05:35.554","Text":"The linear polymers like side by side in the cell wall cross-linked by short peptides."},{"Start":"05:35.554 ","End":"05:39.260","Text":"These pentapeptide that we mentioned that a"},{"Start":"05:39.260 ","End":"05:43.640","Text":"cross-linked the exact structure of which depends on the bacterial species."},{"Start":"05:43.640 ","End":"05:47.285","Text":"You have Gram positive and Gram negative and this is where it changes"},{"Start":"05:47.285 ","End":"05:52.190","Text":"a little bit and I will show it and illustrate just so you understand,"},{"Start":"05:52.190 ","End":"05:56.540","Text":"but you don\u0027t necessarily need to know the details of this."},{"Start":"05:56.540 ","End":"06:03.230","Text":"These peptide cross-links welded polysaccharide chains into strong sheet that"},{"Start":"06:03.230 ","End":"06:05.930","Text":"envelops the entire cell and prevent"},{"Start":"06:05.930 ","End":"06:10.355","Text":"cellular swelling and lysis due to the osmotic entry of water."},{"Start":"06:10.355 ","End":"06:17.630","Text":"It protects the bacteria so they can be resilient in different osmotic pressures."},{"Start":"06:17.630 ","End":"06:20.374","Text":"If we look at the Gram negative,"},{"Start":"06:20.374 ","End":"06:25.590","Text":"you see here an example of a Gram negative bacteria is E. coli,"},{"Start":"06:25.910 ","End":"06:29.369","Text":"Escherichia coli, you see the same legend."},{"Start":"06:29.369 ","End":"06:31.370","Text":"You have the gene M,"},{"Start":"06:31.370 ","End":"06:37.515","Text":"the acetylglucosamine and the acetyl muramic acid,"},{"Start":"06:37.515 ","End":"06:40.845","Text":"G and M. It looks the same,"},{"Start":"06:40.845 ","End":"06:42.260","Text":"when you step back."},{"Start":"06:42.260 ","End":"06:43.850","Text":"Where\u0027s the difference?"},{"Start":"06:43.850 ","End":"06:49.850","Text":"It\u0027s in the crosslinking of the peptides between the chains."},{"Start":"06:49.850 ","End":"06:53.375","Text":"While here you have a pentapeptide,"},{"Start":"06:53.375 ","End":"06:56.810","Text":"a peptide of 5 that is linked by a pentaglycine,"},{"Start":"06:56.810 ","End":"07:02.924","Text":"5 molecules here do you have the tetra peptide."},{"Start":"07:02.924 ","End":"07:07.280","Text":"In this case the tetra that is 4."},{"Start":"07:07.280 ","End":"07:09.215","Text":"You have a tetrapeptide,"},{"Start":"07:09.215 ","End":"07:12.110","Text":"alanine, glycine, DAP, and d-alanine."},{"Start":"07:12.110 ","End":"07:13.610","Text":"There\u0027s 4 of them,"},{"Start":"07:13.610 ","End":"07:19.405","Text":"and then you have the peptide link 3-4 that links these together,"},{"Start":"07:19.405 ","End":"07:21.950","Text":"which is different from the pentapeptide link."},{"Start":"07:21.950 ","End":"07:25.030","Text":"The difference between the Gram positive bacteria and the Gram"},{"Start":"07:25.030 ","End":"07:28.685","Text":"negative is not in the actual chain itself,"},{"Start":"07:28.685 ","End":"07:31.505","Text":"not in the linear polymer,"},{"Start":"07:31.505 ","End":"07:37.310","Text":"rather in the cross linkage by the short peptides, that\u0027s what differentiates."},{"Start":"07:37.310 ","End":"07:39.350","Text":"When you look at the Gram negative bacteria,"},{"Start":"07:39.350 ","End":"07:42.230","Text":"here we have the example of Helicobacter versus E. coli."},{"Start":"07:42.230 ","End":"07:45.770","Text":"You see the membrane protein is actually made of"},{"Start":"07:45.770 ","End":"07:49.655","Text":"2 layers of the membrane, the cellular membrane,"},{"Start":"07:49.655 ","End":"07:53.840","Text":"the phospholipid membrane with the peptidoglycan in"},{"Start":"07:53.840 ","End":"08:00.475","Text":"between the membranes as a thinner layer that comes between."},{"Start":"08:00.475 ","End":"08:07.380","Text":"Basically you have these structural heteropolysaccharides made a Beta-1,"},{"Start":"08:07.380 ","End":"08:10.650","Text":"4-linked N-acetylglucosamine as in"},{"Start":"08:10.650 ","End":"08:15.245","Text":"chitin alternating with N-acetylmuramic acid residues,"},{"Start":"08:15.245 ","End":"08:18.140","Text":"and needs to form these linear chains."},{"Start":"08:18.140 ","End":"08:21.950","Text":"Then you have a chain that"},{"Start":"08:21.950 ","End":"08:26.480","Text":"is linked to its neighboring chains because the linear polymers,"},{"Start":"08:26.480 ","End":"08:28.970","Text":"these chains by side by side in the cell wall,"},{"Start":"08:28.970 ","End":"08:31.535","Text":"and they\u0027re cross-linked by short peptides."},{"Start":"08:31.535 ","End":"08:37.575","Text":"You have these peptide chains that are linked by cross peptide linkages"},{"Start":"08:37.575 ","End":"08:43.835","Text":"and that\u0027s what forms the super strong structure that envelopes the entire cell."},{"Start":"08:43.835 ","End":"08:46.625","Text":"Now, again, the peptide cross-links,"},{"Start":"08:46.625 ","End":"08:51.140","Text":"well the polysaccharide chains and taste strong sheath that envelopes the entire cell and"},{"Start":"08:51.140 ","End":"08:56.420","Text":"prevent cellular swelling and lysis due to the osmotic entry of water."},{"Start":"08:56.420 ","End":"09:00.799","Text":"The enzyme lysozyme kills bacteria by hydrolyzing"},{"Start":"09:00.799 ","End":"09:06.470","Text":"the Beta-1,4 glycosidic bond between acetyl glucosamine and N-acetylmuramic acid."},{"Start":"09:06.470 ","End":"09:10.160","Text":"Remember we talked about the enzyme that breaks down chitin,"},{"Start":"09:10.160 ","End":"09:15.180","Text":"but it breaks down the links between N-acetylglucosamine units."},{"Start":"09:15.180 ","End":"09:19.370","Text":"Here we have acetyl glucosamine that is linked to N-acetylmuramic acid."},{"Start":"09:19.370 ","End":"09:22.250","Text":"Therefore, there\u0027s a different enzyme that can"},{"Start":"09:22.250 ","End":"09:25.275","Text":"hydrolyze these Beta-1,4 glycosidic bonds,"},{"Start":"09:25.275 ","End":"09:27.525","Text":"and this enzyme is lysozyme."},{"Start":"09:27.525 ","End":"09:30.545","Text":"By hydrolyzing, breaking these bonds that kills bacteria"},{"Start":"09:30.545 ","End":"09:33.610","Text":"because it breaks apart the cell wall,"},{"Start":"09:33.610 ","End":"09:39.680","Text":"and now the bacteria is permeable to things enter and exit."},{"Start":"09:39.680 ","End":"09:43.970","Text":"Lysozyme is present in human tears,"},{"Start":"09:43.970 ","End":"09:48.530","Text":"presumably as a defense against bacterial infections of the eye or 1 of"},{"Start":"09:48.530 ","End":"09:53.900","Text":"our immune defenses against microbes that try to enter through our eyes,"},{"Start":"09:53.900 ","End":"09:56.990","Text":"which has an orifice that things can enter other"},{"Start":"09:56.990 ","End":"10:00.470","Text":"than the area where we have skin that protects us."},{"Start":"10:00.470 ","End":"10:05.975","Text":"It is also produced by certain bacterial viruses,"},{"Start":"10:05.975 ","End":"10:09.430","Text":"phages, viruses that infect bacteria."},{"Start":"10:09.430 ","End":"10:14.270","Text":"This is to ensure they\u0027re released from the host bacteria cell and essential step of"},{"Start":"10:14.270 ","End":"10:20.540","Text":"the viral infection cycle because if they can\u0027t break down the bonds of a cell wall,"},{"Start":"10:20.540 ","End":"10:23.420","Text":"they can\u0027t get through the cell wall because it\u0027s not"},{"Start":"10:23.420 ","End":"10:26.300","Text":"porous like the phospholipid membrane."},{"Start":"10:26.300 ","End":"10:32.750","Text":"In order to get through so that can infect and spread and infect other bacteria."},{"Start":"10:32.750 ","End":"10:37.250","Text":"It needs to be able to break these links and therefore,"},{"Start":"10:37.250 ","End":"10:43.435","Text":"certain bacterial viruses also produce the lysozyme enzyme."},{"Start":"10:43.435 ","End":"10:46.400","Text":"Penicillin, the antibiotic,"},{"Start":"10:46.400 ","End":"10:52.070","Text":"the first and most famous one and related antibiotics kill,"},{"Start":"10:52.070 ","End":"10:56.750","Text":"bacteria by preventing synthesis of these cross-links,"},{"Start":"10:56.750 ","End":"11:00.875","Text":"leaving the cell wall too weak to resist osmotic lysis"},{"Start":"11:00.875 ","End":"11:05.350","Text":"and therefore the bacteria cells lyse the burst."},{"Start":"11:05.350 ","End":"11:08.060","Text":"Just to get over the idea,"},{"Start":"11:08.060 ","End":"11:10.170","Text":"we have Gram positive and Gram negative bacteria,"},{"Start":"11:10.170 ","End":"11:13.850","Text":"the idea is through basically the same with the difference in the peptide chain."},{"Start":"11:13.850 ","End":"11:16.715","Text":"You see the peptidoglycan of the cell wall"},{"Start":"11:16.715 ","End":"11:20.700","Text":"of Staphylococcus Aureus a Gram positive bacteria."},{"Start":"11:20.700 ","End":"11:22.940","Text":"Peptide strings of these colored spheres,"},{"Start":"11:22.940 ","End":"11:25.160","Text":"you see it in both covalently linked"},{"Start":"11:25.160 ","End":"11:29.900","Text":"the N-acetylmuramic acid residues in neighboring polysaccharide chains."},{"Start":"11:29.900 ","End":"11:34.394","Text":"The link, specifically the N-acetylmuramic acid."},{"Start":"11:34.394 ","End":"11:39.680","Text":"Now, note the mixture of the L and D amino acids in the peptide."},{"Start":"11:39.680 ","End":"11:43.070","Text":"You have L alanine, D-glucose, amino lysine."},{"Start":"11:43.070 ","End":"11:48.319","Text":"The Gram positive bacteria have a pentaglycine chain in the crosslink."},{"Start":"11:48.319 ","End":"11:54.820","Text":"The pentaglycine 5 glycines and Gram negative bacteria such as E. coli."},{"Start":"11:54.820 ","End":"11:57.109","Text":"Back this pentaglycine instead,"},{"Start":"11:57.109 ","End":"12:01.085","Text":"the terminal D-alanine residue of 1 tetrapeptide."},{"Start":"12:01.085 ","End":"12:05.660","Text":"The peptide of 4 is attached directly to"},{"Start":"12:05.660 ","End":"12:11.780","Text":"a neighboring tetrapeptide through either a lysine or a lysine like amino acid,"},{"Start":"12:11.780 ","End":"12:14.105","Text":"that amino penmalic acid."},{"Start":"12:14.105 ","End":"12:19.940","Text":"Here you have a peptide link between 3-4 of the tetrapeptide."},{"Start":"12:19.940 ","End":"12:29.465","Text":"It would be here through the L lysine that would be here or DAP, the diaminopimelic acid."},{"Start":"12:29.465 ","End":"12:34.715","Text":"You don\u0027t need to memorize these things it\u0027s just so you understand the idea."},{"Start":"12:34.715 ","End":"12:38.585","Text":"It\u0027s a little different but the same concept of the linear chains,"},{"Start":"12:38.585 ","End":"12:44.330","Text":"the peptidoglycan that make up the bacterial cell wall and algae cell wall."},{"Start":"12:44.330 ","End":"12:48.350","Text":"With this we completed Part 1 of 2 parts in"},{"Start":"12:48.350 ","End":"12:52.310","Text":"the lesson on heteropolysaccharides that are structural."},{"Start":"12:52.310 ","End":"12:55.265","Text":"Remember before we talked about homopolysaccharides."},{"Start":"12:55.265 ","End":"12:58.220","Text":"In this section, we covered the types of"},{"Start":"12:58.220 ","End":"13:03.545","Text":"structural heteropolysaccharides and the structure of such polysaccharides."},{"Start":"13:03.545 ","End":"13:06.450","Text":"Let\u0027s meet back at Part 2."}],"ID":30520},{"Watched":false,"Name":"Heteropolysaccharides - Structure Part 2","Duration":"6m 29s","ChapterTopicVideoID":28972,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.860","Text":"Welcome back to heteropolysaccharides that serve a structural role."},{"Start":"00:04.860 ","End":"00:06.270","Text":"This is Part 2."},{"Start":"00:06.270 ","End":"00:10.410","Text":"In this section, we will further dive into the types of"},{"Start":"00:10.410 ","End":"00:13.950","Text":"structural heteropolysaccharides and specifically talk about agar"},{"Start":"00:13.950 ","End":"00:18.090","Text":"and agarose and the characteristics and structure of these."},{"Start":"00:18.090 ","End":"00:20.655","Text":"Certain marine red algae,"},{"Start":"00:20.655 ","End":"00:22.905","Text":"including some of the seaweeds,"},{"Start":"00:22.905 ","End":"00:25.830","Text":"have cell walls that contain agar,"},{"Start":"00:25.830 ","End":"00:31.290","Text":"a mixture of sulfated heteropolysaccharides made up of D-galactose"},{"Start":"00:31.290 ","End":"00:36.885","Text":"and an L-galactose derivative ether-linked between C-3 and C-6,"},{"Start":"00:36.885 ","End":"00:40.380","Text":"a carbon 3 and 6 of the structure,"},{"Start":"00:40.380 ","End":"00:43.300","Text":"so ether-linked as the type of weed."},{"Start":"00:43.300 ","End":"00:45.635","Text":"Hopefully you remember this from chemistry,"},{"Start":"00:45.635 ","End":"00:47.105","Text":"but in broad terms,"},{"Start":"00:47.105 ","End":"00:50.840","Text":"an ether-link is a linkage between carbon, oxygen."},{"Start":"00:50.840 ","End":"00:55.220","Text":"Carbon that is bent like a, C,"},{"Start":"00:55.220 ","End":"00:58.715","Text":"O C, but this doesn\u0027t necessarily have to be a carbon,"},{"Start":"00:58.715 ","End":"01:01.580","Text":"it can be, right and R, it can be a group."},{"Start":"01:01.580 ","End":"01:05.000","Text":"That is what the ether-link is."},{"Start":"01:05.000 ","End":"01:09.065","Text":"There\u0027s ether versus ester links,"},{"Start":"01:09.065 ","End":"01:11.630","Text":"and we will mention this here."},{"Start":"01:11.630 ","End":"01:15.650","Text":"But ethers are the chemical compounds that have a single bonded oxygen in-between"},{"Start":"01:15.650 ","End":"01:18.860","Text":"2 simple hydrocarbon chains and esters are chemical compounds that"},{"Start":"01:18.860 ","End":"01:22.535","Text":"have a double bond between oxygen and adjacent carbon."},{"Start":"01:22.535 ","End":"01:26.610","Text":"It would have this double bond for the ester."},{"Start":"01:26.610 ","End":"01:30.377","Text":"These are terms you should know from chemistry,"},{"Start":"01:30.377 ","End":"01:32.825","Text":"it contributes to the chains in the link."},{"Start":"01:32.825 ","End":"01:37.340","Text":"Just an FYI going back to what we\u0027re talking about here."},{"Start":"01:37.340 ","End":"01:41.475","Text":"These red algae have cell walls that contain agar."},{"Start":"01:41.475 ","End":"01:44.810","Text":"Agar is a mixture of sulfated heteropolysaccharides made up of"},{"Start":"01:44.810 ","End":"01:50.045","Text":"D-galactose and L-galactose ether-linked between C-3 and C-6."},{"Start":"01:50.045 ","End":"01:53.720","Text":"You see this is the bond of ether and this is what you\u0027re seeing,"},{"Start":"01:53.720 ","End":"01:57.860","Text":"the carbon and an oxygen, agarose."},{"Start":"01:57.860 ","End":"02:04.680","Text":"You see the molecule and it\u0027s a beta-1,4 linked D-glucose units,"},{"Start":"02:05.170 ","End":"02:10.665","Text":"1 carbon and 4 Beta-linked,"},{"Start":"02:10.665 ","End":"02:15.390","Text":"and you have the D-galactose Beta 1,4 linkage with a 3,"},{"Start":"02:15.390 ","End":"02:18.705","Text":"6-anhydro-L-GA, the galactose 2S,"},{"Start":"02:18.705 ","End":"02:27.565","Text":"so basically you have this linkage that creates the chain that makes up agar,"},{"Start":"02:27.565 ","End":"02:32.805","Text":"which is the heteropolysaccharide found in many red algae."},{"Start":"02:32.805 ","End":"02:38.255","Text":"Agar is a complex mixture of various polysaccharides,"},{"Start":"02:38.255 ","End":"02:41.225","Text":"all with the same backbone structure,"},{"Start":"02:41.225 ","End":"02:46.540","Text":"but substituted to varying degrees with sulfate and pyruvate,"},{"Start":"02:46.540 ","End":"02:49.005","Text":"so we have sulfate here."},{"Start":"02:49.005 ","End":"02:53.255","Text":"This is what is substituted in this galactose,"},{"Start":"02:53.255 ","End":"03:02.050","Text":"and this is what berries in the saccharides that make up the polysaccharide of agar."},{"Start":"03:02.050 ","End":"03:06.440","Text":"The 2 major components of agar are"},{"Start":"03:06.440 ","End":"03:14.220","Text":"the unbranched polymer agarose and a branch component, agaropectin."},{"Start":"03:14.810 ","End":"03:17.510","Text":"So 2 major components of agar are"},{"Start":"03:17.510 ","End":"03:21.505","Text":"the unbranched polymer agarose and a branched component,"},{"Start":"03:21.505 ","End":"03:24.421","Text":"agaropectin, so you have agarose here,"},{"Start":"03:24.421 ","End":"03:26.405","Text":"this creates the linear."},{"Start":"03:26.405 ","End":"03:28.820","Text":"Agaropectin will be branched."},{"Start":"03:28.820 ","End":"03:32.660","Text":"Agarose is the other component with the fewest charged groups,"},{"Start":"03:32.660 ","End":"03:34.850","Text":"the fewest sulfates and pervades."},{"Start":"03:34.850 ","End":"03:37.110","Text":"You see sulfate."},{"Start":"03:37.110 ","End":"03:42.590","Text":"Agarose, what we see here is the agar component with a fuse charged groups."},{"Start":"03:42.590 ","End":"03:45.275","Text":"It has a gel forming property,"},{"Start":"03:45.275 ","End":"03:47.600","Text":"which makes it useful in the laboratory when"},{"Start":"03:47.600 ","End":"03:50.000","Text":"a suspension of agarose and water is heated and cooled,"},{"Start":"03:50.000 ","End":"03:51.960","Text":"the agarose forms a double helix,"},{"Start":"03:51.960 ","End":"03:58.160","Text":"2 molecules and parallel orientation twist together with a helix repeat of 3 residues."},{"Start":"03:58.160 ","End":"04:00.860","Text":"Water molecules are trapped in the central cavity"},{"Start":"04:00.860 ","End":"04:03.650","Text":"and these structures and turn associate with each other to form"},{"Start":"04:03.650 ","End":"04:06.080","Text":"a gel because of these water molecules are"},{"Start":"04:06.080 ","End":"04:09.570","Text":"3-dimensional matrix that traps large amounts of water."},{"Start":"04:09.570 ","End":"04:14.230","Text":"Agarose gels are used as supports for the electrophoretic separation of nucleic acids,"},{"Start":"04:14.230 ","End":"04:17.270","Text":"do when you run a gel in the lab to separate"},{"Start":"04:17.270 ","End":"04:21.230","Text":"nucleic acids like DNA by size or any whatnot,"},{"Start":"04:21.230 ","End":"04:24.595","Text":"you use an agarose gel."},{"Start":"04:24.595 ","End":"04:27.515","Text":"These are an essential part of the DNA sequencing process."},{"Start":"04:27.515 ","End":"04:30.815","Text":"On the other hand, we use agar to grow bacteria."},{"Start":"04:30.815 ","End":"04:34.310","Text":"It\u0027s a very easy substance to heat up,"},{"Start":"04:34.310 ","End":"04:38.165","Text":"make it liquid, and then let it melt in whatever shape we want."},{"Start":"04:38.165 ","End":"04:39.875","Text":"In a Petri dish,"},{"Start":"04:39.875 ","End":"04:46.465","Text":"we will put an agar and then it will solidify and then we can grow bacteria on it."},{"Start":"04:46.465 ","End":"04:52.940","Text":"As mentioned, agar is used for the growth of bacterial colonies,"},{"Start":"04:52.940 ","End":"04:56.900","Text":"forms a surface on which bacteria can grow."},{"Start":"04:56.900 ","End":"04:59.240","Text":"Another commercial use of agars for"},{"Start":"04:59.240 ","End":"05:02.330","Text":"the capsules in which some vitamins and drugs are packaged,"},{"Start":"05:02.330 ","End":"05:07.340","Text":"the dried agar material dissolves readily in the stomach and is metabolic inert,"},{"Start":"05:07.340 ","End":"05:10.295","Text":"meaning non-reactive, doesn\u0027t have any effect biologically."},{"Start":"05:10.295 ","End":"05:14.120","Text":"When you take certain pills and they have this soft component on the outside,"},{"Start":"05:14.120 ","End":"05:21.710","Text":"that\u0027s not [inaudible] because it\u0027s hardened but is soft a little bit like a capsule."},{"Start":"05:21.710 ","End":"05:27.515","Text":"Some of these are made of agar and the advantage is that they are dissolved,"},{"Start":"05:27.515 ","End":"05:30.710","Text":"broken apart in our stomach."},{"Start":"05:31.160 ","End":"05:34.239","Text":"We\u0027re looking here at the agarose."},{"Start":"05:34.239 ","End":"05:37.960","Text":"This is the agar component with the fewest charged groups,"},{"Start":"05:37.960 ","End":"05:43.825","Text":"and you see here the repeating units consist of D-galactose Beta-1,4 linked 2, 3,"},{"Start":"05:43.825 ","End":"05:50.495","Text":"6-anhydro-L-Galactose in which an etherin connects C-3 and C-6."},{"Start":"05:50.495 ","End":"05:54.910","Text":"These units are joined by an Alpha-1,3-glycosidic link to form a polymer,"},{"Start":"05:54.910 ","End":"05:59.290","Text":"600-700 residues along a small fraction of"},{"Start":"05:59.290 ","End":"06:07.705","Text":"the 3,6-anhydro-galactose residues have a sulfate ester at C-2 as shown here."},{"Start":"06:07.705 ","End":"06:13.680","Text":"Basically this is the structure of agarose,"},{"Start":"06:13.680 ","End":"06:16.890","Text":"that is a unit of agar."},{"Start":"06:16.890 ","End":"06:19.040","Text":"With that, we completed the section on"},{"Start":"06:19.040 ","End":"06:23.580","Text":"heteropolysaccharides for structure within polysaccharides."},{"Start":"06:23.580 ","End":"06:26.330","Text":"We went over types of structural heteropolysaccharides"},{"Start":"06:26.330 ","End":"06:29.640","Text":"and the characteristics of such polysaccharides."}],"ID":30521},{"Watched":false,"Name":"Exercise 14","Duration":"4m 49s","ChapterTopicVideoID":28973,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.970","Text":"We talked about heteropolysaccharides that serve a function in structure."},{"Start":"00:05.970 ","End":"00:08.475","Text":"Let\u0027s test our knowledge with an exercise."},{"Start":"00:08.475 ","End":"00:10.215","Text":"Which statement is false?"},{"Start":"00:10.215 ","End":"00:14.400","Text":"A, the rigid component of bacterial cell walls is a heteropolymer."},{"Start":"00:14.400 ","End":"00:17.010","Text":"B, the linear polymers are crosslinked by"},{"Start":"00:17.010 ","End":"00:20.685","Text":"short peptides which weld the polysaccharide chains into a strong cover."},{"Start":"00:20.685 ","End":"00:23.430","Text":"C, penicillin kills bacteria by preventing"},{"Start":"00:23.430 ","End":"00:26.175","Text":"synthesis of the cross-links of their cell walls."},{"Start":"00:26.175 ","End":"00:31.315","Text":"D, certain marine red algae have cell walls that contain agar a heteropolysaccharide,"},{"Start":"00:31.315 ","End":"00:35.585","Text":"and E, agarose is the agar component with the most charged groups."},{"Start":"00:35.585 ","End":"00:40.310","Text":"Let\u0027s go by this 1 by 1 and see which of these statements is false."},{"Start":"00:40.310 ","End":"00:42.530","Text":"Let\u0027s start with the first one. The rigid component of"},{"Start":"00:42.530 ","End":"00:45.200","Text":"bacterial cell walls is a heteropolymer."},{"Start":"00:45.200 ","End":"00:51.180","Text":"Well, we are talking about heteropolymers as being the structural component,"},{"Start":"00:51.180 ","End":"00:54.590","Text":"and we mentioned that they are the structural components of"},{"Start":"00:54.590 ","End":"00:59.300","Text":"bacterial cell walls and some algae therefore this seems like a true statement,"},{"Start":"00:59.300 ","End":"01:02.210","Text":"so we can say this is not our answer."},{"Start":"01:02.210 ","End":"01:08.660","Text":"If you remember, we have homopolymers that make up cell walls of plants,"},{"Start":"01:08.660 ","End":"01:11.285","Text":"and those are the cellulose,"},{"Start":"01:11.285 ","End":"01:14.090","Text":"and within insects it is chitin."},{"Start":"01:14.090 ","End":"01:16.250","Text":"But for bacterial cell walls we have"},{"Start":"01:16.250 ","End":"01:20.750","Text":"the heteropolymer as the rigid component of the bacterial cell wall."},{"Start":"01:20.750 ","End":"01:23.390","Text":"B, the linear polymers are crosslinked by"},{"Start":"01:23.390 ","End":"01:27.095","Text":"short peptides which weld the polysaccharide chains into strong cover."},{"Start":"01:27.095 ","End":"01:31.850","Text":"We did say that there are peptides that link"},{"Start":"01:31.850 ","End":"01:37.430","Text":"these linear chains that make up this heteropolymers,"},{"Start":"01:37.430 ","End":"01:40.805","Text":"and they link it together and create a strong sheet"},{"Start":"01:40.805 ","End":"01:45.780","Text":"that creates this strong cover, this exoskeleton."},{"Start":"01:45.780 ","End":"01:48.710","Text":"Now we mentioned that there\u0027s gram-positive and gram-negative"},{"Start":"01:48.710 ","End":"01:52.490","Text":"bacteria that have different arrangements of this,"},{"Start":"01:52.490 ","End":"01:57.840","Text":"and we said also in algae that there exists these links,"},{"Start":"01:57.840 ","End":"02:01.310","Text":"and though the links are a little different in gram-positive you"},{"Start":"02:01.310 ","End":"02:04.415","Text":"have the pentapeptide like acidic linkage,"},{"Start":"02:04.415 ","End":"02:10.580","Text":"and within the negative it is just the peptides linked to each other, the tetrapeptide."},{"Start":"02:10.580 ","End":"02:12.470","Text":"But the idea is that"},{"Start":"02:12.470 ","End":"02:17.980","Text":"these cross-linked short peptides are what gives it this really strong structure,"},{"Start":"02:17.980 ","End":"02:21.395","Text":"so this is a correct statement and therefore is not our answer."},{"Start":"02:21.395 ","End":"02:23.420","Text":"C, penicillin."},{"Start":"02:23.420 ","End":"02:27.645","Text":"Penicillin, the first and most famous antibiotic discovered,"},{"Start":"02:27.645 ","End":"02:32.090","Text":"and its derivatives are family like antibiotics kill bacteria by"},{"Start":"02:32.090 ","End":"02:36.710","Text":"preventing synthesis of the cross-links of their cell walls."},{"Start":"02:36.710 ","End":"02:39.755","Text":"They basically break these cross-links."},{"Start":"02:39.755 ","End":"02:47.615","Text":"The individual linear chains do not make this strong sheath and thus it allows for"},{"Start":"02:47.615 ","End":"02:51.320","Text":"osmotic pressure to occur with the cells to burst and for"},{"Start":"02:51.320 ","End":"02:55.655","Text":"things to get through the cell wall and therefore it kills bacteria."},{"Start":"02:55.655 ","End":"02:58.960","Text":"This is a true statement and therefore is not our answer."},{"Start":"02:58.960 ","End":"03:01.670","Text":"It\u0027s going to D, certain marine red algae,"},{"Start":"03:01.670 ","End":"03:05.780","Text":"we mentioned they also have heteropolymers as their structural component."},{"Start":"03:05.780 ","End":"03:07.930","Text":"There\u0027s structural heteropolymers."},{"Start":"03:07.930 ","End":"03:10.605","Text":"They have cell walls that contain agar,"},{"Start":"03:10.605 ","End":"03:13.385","Text":"a heteropolysaccharide, and yes,"},{"Start":"03:13.385 ","End":"03:16.460","Text":"we mentioned that for certain marine red algae,"},{"Start":"03:16.460 ","End":"03:20.185","Text":"they\u0027re heteropolysaccharide is agar,"},{"Start":"03:20.185 ","End":"03:22.790","Text":"which has a component that gives it"},{"Start":"03:22.790 ","End":"03:27.035","Text":"a little bit more flexibility because it has agarose in it,"},{"Start":"03:27.035 ","End":"03:30.575","Text":"and agarose is an agar component."},{"Start":"03:30.575 ","End":"03:35.085","Text":"Let\u0027s just go back to D. This seems like a true statement."},{"Start":"03:35.085 ","End":"03:37.035","Text":"Again, doesn\u0027t seem like our answer,"},{"Start":"03:37.035 ","End":"03:40.595","Text":"and we\u0027re talking about agarose is the agar component,"},{"Start":"03:40.595 ","End":"03:45.300","Text":"and we are saying here that agaroses is agar component with the most charged groups."},{"Start":"03:45.300 ","End":"03:49.905","Text":"Remember we mentioned the charged groups being sulfates and pyruvate."},{"Start":"03:49.905 ","End":"03:54.125","Text":"That is the difference in the many different components of"},{"Start":"03:54.125 ","End":"03:58.085","Text":"agar that can make up agar the heteropolysaccharide."},{"Start":"03:58.085 ","End":"04:01.610","Text":"It is the degree of charged groups,"},{"Start":"04:01.610 ","End":"04:06.230","Text":"pyruvates and sulfates that are in that molecule."},{"Start":"04:06.230 ","End":"04:13.160","Text":"Agarose was specifically mentioned as the agar component with the least charged groups."},{"Start":"04:13.160 ","End":"04:17.300","Text":"Therefore, this is false and this is our correct answer."},{"Start":"04:17.300 ","End":"04:21.425","Text":"Agarose is the agar component with the most charged groups."},{"Start":"04:21.425 ","End":"04:23.525","Text":"What would make it true?"},{"Start":"04:23.525 ","End":"04:29.030","Text":"Would be if we said agarose is the agar component with the fewest charged groups,"},{"Start":"04:29.030 ","End":"04:35.325","Text":"and again, the charged groups are sulfates and pyruvates."},{"Start":"04:35.325 ","End":"04:37.460","Text":"In the figure that we introduced in that lesson,"},{"Start":"04:37.460 ","End":"04:42.890","Text":"we showed agarose with a sulfate linked to the molecule."},{"Start":"04:42.890 ","End":"04:45.305","Text":"If you need a reminder,"},{"Start":"04:45.305 ","End":"04:47.360","Text":"you can go back to the lesson,"},{"Start":"04:47.360 ","End":"04:50.490","Text":"and with that, we completed this exercise."}],"ID":30522},{"Watched":false,"Name":"Exercise 15","Duration":"3m 27s","ChapterTopicVideoID":28974,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.400","Text":"We have another exercise that cover the lesson, non-structural heteropolysaccharides."},{"Start":"00:05.400 ","End":"00:11.610","Text":"Part 1, what is the enzyme mentioned that kills bacteria and how does it do so?"},{"Start":"00:11.610 ","End":"00:18.120","Text":"The enzyme mentioned is lysozyme and this kills bacteria and it does so by hydrolyzing"},{"Start":"00:18.120 ","End":"00:24.720","Text":"the Beta-1,4 glycosidic bond between N-acetylglucosamine and N-acetylmuramic acid."},{"Start":"00:24.720 ","End":"00:28.350","Text":"Remember, we mentioned that bacteria cell walls are made up of"},{"Start":"00:28.350 ","End":"00:33.810","Text":"alternating units of N-acetylglucosamine and N-acetylmuramic acid."},{"Start":"00:33.810 ","End":"00:38.240","Text":"There\u0027s a chain and the thicker it was just marked as m"},{"Start":"00:38.240 ","End":"00:43.590","Text":"for uremic acid and then g for glucosamine."},{"Start":"00:43.590 ","End":"00:47.580","Text":"It\u0027s a chain of these alternating and they have"},{"Start":"00:47.580 ","End":"00:52.355","Text":"the Beta-1,4 glycosidic bond that combines them."},{"Start":"00:52.355 ","End":"00:58.440","Text":"These are linked together furthermore with neighboring chains by"},{"Start":"00:58.440 ","End":"01:06.675","Text":"a peptide bond in between the acetylmuramic acid, acids neighboring ones."},{"Start":"01:06.675 ","End":"01:10.400","Text":"The lysozyme kills bacteria by breaking"},{"Start":"01:10.400 ","End":"01:15.690","Text":"these links and therefore the chains are broken and come apart."},{"Start":"01:15.860 ","End":"01:21.875","Text":"It breaks the bonds between the molecules that make up the polysaccharide."},{"Start":"01:21.875 ","End":"01:25.760","Text":"Part 2, give an example of where the enzyme is present."},{"Start":"01:25.760 ","End":"01:30.815","Text":"We mentioned a couple of examples of where lysozyme is found."},{"Start":"01:30.815 ","End":"01:34.340","Text":"Well, lysozyme is present in human tears,"},{"Start":"01:34.340 ","End":"01:37.370","Text":"presumably as a defense against bacterial infections of the eye,"},{"Start":"01:37.370 ","End":"01:40.445","Text":"because we generally as our immune defense,"},{"Start":"01:40.445 ","End":"01:43.430","Text":"have the non-specific immune,"},{"Start":"01:43.430 ","End":"01:48.645","Text":"which is our innate immune that eliminates pathogens from entering our body."},{"Start":"01:48.645 ","End":"01:51.275","Text":"Our biggest line of defense is our skin."},{"Start":"01:51.275 ","End":"01:55.460","Text":"Things generally can\u0027t go through our skin unless our skin is broken."},{"Start":"01:55.460 ","End":"01:58.610","Text":"That\u0027s why when we get cuts we can get infected and an infection in"},{"Start":"01:58.610 ","End":"02:02.090","Text":"the cut because it\u0027s open for pathogens to enter,"},{"Start":"02:02.090 ","End":"02:04.175","Text":"but generally they can\u0027t get through our skin."},{"Start":"02:04.175 ","End":"02:05.810","Text":"Otherwise, we have orifices,"},{"Start":"02:05.810 ","End":"02:08.120","Text":"they can get through our mouth and that\u0027s where we"},{"Start":"02:08.120 ","End":"02:10.730","Text":"have saliva enzymes that break it down."},{"Start":"02:10.730 ","End":"02:12.665","Text":"They can get through our nose,"},{"Start":"02:12.665 ","End":"02:14.280","Text":"our nasal, pharynx."},{"Start":"02:14.280 ","End":"02:18.740","Text":"That\u0027s why we have cilia and little hairs that reduce things from getting through."},{"Start":"02:18.740 ","End":"02:19.940","Text":"We have mucus."},{"Start":"02:19.940 ","End":"02:24.020","Text":"In our eyes we also have eyelashes and our ears we have little ears and titles."},{"Start":"02:24.020 ","End":"02:28.280","Text":"Basically, human tears are another form of"},{"Start":"02:28.280 ","End":"02:32.645","Text":"defense against bacterial infections because they have lysozyme"},{"Start":"02:32.645 ","End":"02:36.710","Text":"in it that break down the bacterial wall and"},{"Start":"02:36.710 ","End":"02:41.315","Text":"they eliminate the entry of bacteria through our eyes to our body."},{"Start":"02:41.315 ","End":"02:43.790","Text":"The other example that was given as lysozyme is"},{"Start":"02:43.790 ","End":"02:47.960","Text":"produced by certain bacterial viruses like phages,"},{"Start":"02:47.960 ","End":"02:53.375","Text":"this allows the viruses to enter and infect."},{"Start":"02:53.375 ","End":"02:57.545","Text":"Furthermore, the viruses use this to ensure their release"},{"Start":"02:57.545 ","End":"03:01.430","Text":"from the host bacterial cell and essential stuff of the viral infection cycle."},{"Start":"03:01.430 ","End":"03:03.740","Text":"Because if they can\u0027t release,"},{"Start":"03:03.740 ","End":"03:10.520","Text":"then the only can spread by lysine or killing the bacteria,"},{"Start":"03:10.520 ","End":"03:12.170","Text":"so by lytic infection,"},{"Start":"03:12.170 ","End":"03:15.410","Text":"but this is not always the needed case."},{"Start":"03:15.410 ","End":"03:18.455","Text":"If they can break down the wall,"},{"Start":"03:18.455 ","End":"03:21.890","Text":"they can exit the bacteria."},{"Start":"03:21.890 ","End":"03:28.500","Text":"With that, we completed this exercise covering structural heteropolysaccharides."}],"ID":30523},{"Watched":false,"Name":"Heteropolysaccharides - Extracellular Matrix Part 1","Duration":"12m 48s","ChapterTopicVideoID":28975,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.720 ","End":"00:05.455","Text":"We are still within the topic of polysaccharides and we"},{"Start":"00:05.455 ","End":"00:10.145","Text":"are talking again about heteropolysaccharides,"},{"Start":"00:10.145 ","End":"00:14.920","Text":"but this time their role in the extracellular matrix."},{"Start":"00:14.920 ","End":"00:18.955","Text":"In this section, we will learn about the extracellular matrix,"},{"Start":"00:18.955 ","End":"00:25.190","Text":"what it is, and about glycosaminoglycans and its various types."},{"Start":"00:25.190 ","End":"00:28.460","Text":"Further delving in the heteropolysaccharides"},{"Start":"00:28.460 ","End":"00:31.780","Text":"in a structural capacity of the extracellular matrix,"},{"Start":"00:31.780 ","End":"00:34.485","Text":"we\u0027re going to split this lesson into 2 parts."},{"Start":"00:34.485 ","End":"00:39.220","Text":"In part 1 of heteropolysaccharides in the extracellular matrix,"},{"Start":"00:39.220 ","End":"00:43.000","Text":"we will learn about the extracellular matrix, this term,"},{"Start":"00:43.000 ","End":"00:47.735","Text":"and about glycosaminoglycan\u0027s composition and structure."},{"Start":"00:47.735 ","End":"00:52.440","Text":"Glycosaminoglycans are heteropolysaccharides of extracellular matrix,"},{"Start":"00:52.440 ","End":"00:56.795","Text":"so remember, we have been covering in this chapter on polysaccharides,"},{"Start":"00:56.795 ","End":"01:00.680","Text":"homopolysaccharides unbranched, branched that serve"},{"Start":"01:00.680 ","End":"01:04.970","Text":"a fuel on structure and heteropolysaccharides branched and unbranched,"},{"Start":"01:04.970 ","End":"01:07.565","Text":"again that serve for fuel or structure."},{"Start":"01:07.565 ","End":"01:14.465","Text":"Now you\u0027re talking about heteropolysaccharides specifically of the extracellular matrix."},{"Start":"01:14.465 ","End":"01:17.415","Text":"The extracellular space in the tissues of"},{"Start":"01:17.415 ","End":"01:21.110","Text":"multi-cellular animals is filled with a gel-like material,"},{"Start":"01:21.110 ","End":"01:24.050","Text":"the extracellular matrix, ECM for short."},{"Start":"01:24.050 ","End":"01:28.580","Text":"It is also called ground substance."},{"Start":"01:28.580 ","End":"01:34.790","Text":"I\u0027m going to most likely use ECM or EM the rest of this lesson."},{"Start":"01:34.790 ","End":"01:39.050","Text":"Now the extracellular matrix holds the cells together"},{"Start":"01:39.050 ","End":"01:43.849","Text":"and provides a porous pathway that allows"},{"Start":"01:43.849 ","End":"01:48.410","Text":"the diffusion of nutrients and oxygen to individual cells because"},{"Start":"01:48.410 ","End":"01:53.810","Text":"there are things that are produced that need to move between different cells."},{"Start":"01:53.810 ","End":"01:58.190","Text":"Now, the extracellular matrix is composed of"},{"Start":"01:58.190 ","End":"02:05.060","Text":"an interlocking meshwork of heteropolysaccharides and fibrous proteins such as collagen,"},{"Start":"02:05.060 ","End":"02:07.705","Text":"elastin, fibronectin, and laminin."},{"Start":"02:07.705 ","End":"02:14.660","Text":"Now in the case of ECM that surrounds fibroblasts and other connective tissue cells,"},{"Start":"02:14.660 ","End":"02:17.720","Text":"it is made of heteropolysaccharides and"},{"Start":"02:17.720 ","End":"02:22.490","Text":"fibrous proteins such as collagen, elastin, fibronectin specifically."},{"Start":"02:22.490 ","End":"02:26.150","Text":"Whereas in basement membrane,"},{"Start":"02:26.150 ","End":"02:32.510","Text":"which is a specialized ECM that underlies epithelial cells,"},{"Start":"02:32.510 ","End":"02:34.925","Text":"it consists of specialized collagens,"},{"Start":"02:34.925 ","End":"02:37.805","Text":"laminins, and heteropolysaccharides."},{"Start":"02:37.805 ","End":"02:44.720","Text":"These heteropolysaccharides are called glycosaminoglycans and are"},{"Start":"02:44.720 ","End":"02:52.890","Text":"a family of linear polymers composed of repeating disaccharide units."},{"Start":"02:53.000 ","End":"03:00.255","Text":"Let\u0027s just take a step back again and go over what we talked about the lessons this far."},{"Start":"03:00.255 ","End":"03:02.705","Text":"We introduced carbohydrates."},{"Start":"03:02.705 ","End":"03:06.395","Text":"We said that they can be classified by size."},{"Start":"03:06.395 ","End":"03:11.690","Text":"You have monosaccharides that are made of 1 sugar molecule with glucose,"},{"Start":"03:11.690 ","End":"03:16.790","Text":"fructose, and galactose being examples, you have disaccharides."},{"Start":"03:16.790 ","End":"03:22.655","Text":"These are molecules that are made of 2 sugar molecules bound together, linked together."},{"Start":"03:22.655 ","End":"03:24.830","Text":"Maltose. It is a chain."},{"Start":"03:24.830 ","End":"03:27.525","Text":"You have glucose, two of them together."},{"Start":"03:27.525 ","End":"03:30.739","Text":"You have a maltose, a disaccharide."},{"Start":"03:30.739 ","End":"03:34.220","Text":"When you have glucose and fructose or fructose and galactose,"},{"Start":"03:34.220 ","End":"03:35.945","Text":"or galactose and galactose,"},{"Start":"03:35.945 ","End":"03:40.660","Text":"you have other disaccharides like a sucrose or lactose."},{"Start":"03:40.660 ","End":"03:45.080","Text":"Then you have chains of monosaccharides,"},{"Start":"03:45.080 ","End":"03:51.860","Text":"multiple units in a chain that range from 2-10,"},{"Start":"03:51.860 ","End":"03:55.595","Text":"and these are called oligosaccharides."},{"Start":"03:55.595 ","End":"04:00.335","Text":"An example of these are raffinose and stachyose which we haven\u0027t mentioned previously,"},{"Start":"04:00.335 ","End":"04:05.620","Text":"but we did mention the most common oligosaccharides are the disaccharides."},{"Start":"04:05.620 ","End":"04:08.510","Text":"Now in this section,"},{"Start":"04:08.510 ","End":"04:13.070","Text":"we\u0027ve been talking about polysaccharides and this mean they have"},{"Start":"04:13.070 ","End":"04:16.265","Text":"10 or more sugar molecules and they could"},{"Start":"04:16.265 ","End":"04:20.120","Text":"be heteropolysaccharides or homopolysaccharides,"},{"Start":"04:20.120 ","End":"04:24.350","Text":"meaning the units are either the same in the polysaccharide,"},{"Start":"04:24.350 ","End":"04:29.300","Text":"which would be a homopolysaccharide or mixes of different monomers,"},{"Start":"04:29.300 ","End":"04:31.415","Text":"and that would make a heteropolysaccharide."},{"Start":"04:31.415 ","End":"04:34.655","Text":"Now, we mentioned starch and glycogen."},{"Start":"04:34.655 ","End":"04:40.020","Text":"These are fuel homopolysaccharides made of glucose,"},{"Start":"04:40.020 ","End":"04:41.899","Text":"and we mentioned cellulose."},{"Start":"04:41.899 ","End":"04:44.180","Text":"This is a structural component."},{"Start":"04:44.180 ","End":"04:49.280","Text":"It can also be used as fuel for herbivores in"},{"Start":"04:49.280 ","End":"04:54.980","Text":"termites that have a symbiotic organisms that can break down cellulose for fuel,"},{"Start":"04:54.980 ","End":"04:59.585","Text":"but mostly cellulose is considered a structural homopolysaccharide."},{"Start":"04:59.585 ","End":"05:04.865","Text":"Now we are talking about glycosaminoglycans that are a family of"},{"Start":"05:04.865 ","End":"05:10.595","Text":"linear polymers composed of repeating disaccharide units."},{"Start":"05:10.595 ","End":"05:17.805","Text":"What we see here are glycosaminoglycans, different ones,"},{"Start":"05:17.805 ","End":"05:20.600","Text":"and you have here the number of"},{"Start":"05:20.600 ","End":"05:25.660","Text":"disaccharides per chain of each type of glycosaminoglycan,"},{"Start":"05:25.660 ","End":"05:29.670","Text":"and you see here the repeating disaccharide."},{"Start":"05:29.670 ","End":"05:34.460","Text":"We said these are family of linear polymers composed of repeating disaccharide units,"},{"Start":"05:34.460 ","End":"05:39.350","Text":"so each one has a specific disaccharide that repeats."},{"Start":"05:39.350 ","End":"05:42.905","Text":"If we look at hyaluronate,"},{"Start":"05:42.905 ","End":"05:49.895","Text":"these are the 2 monosaccharides that are bound as a disaccharide."},{"Start":"05:49.895 ","End":"05:54.845","Text":"This is what repeats in the chain for chondroitin, keratin sulfate,"},{"Start":"05:54.845 ","End":"06:04.025","Text":"we are seeing the disaccharide made of the two individual monosaccharides."},{"Start":"06:04.025 ","End":"06:06.560","Text":"You have the one monosaccharide, the second monosaccharide."},{"Start":"06:06.560 ","End":"06:07.910","Text":"This forms a disaccharide,"},{"Start":"06:07.910 ","End":"06:15.610","Text":"heparin is made of these 2 linked together in succession to form the chain."},{"Start":"06:16.040 ","End":"06:18.705","Text":"For the case of hyaluronate,"},{"Start":"06:18.705 ","End":"06:22.820","Text":"you have about 50,000 of these disaccharides in a chain."},{"Start":"06:22.820 ","End":"06:30.055","Text":"For heparin, you have 15-90 that form the glycosaminoglycan that\u0027s called heparin."},{"Start":"06:30.055 ","End":"06:36.920","Text":"One of the two monosaccharides is always either an N-acetylglucosamine and remember we"},{"Start":"06:36.920 ","End":"06:43.835","Text":"introduced this first in the topic when we talked about in the lesson on chitin,"},{"Start":"06:43.835 ","End":"06:51.185","Text":"the homopolysaccharide that is a structural component in insects and crustaceans, etc."},{"Start":"06:51.185 ","End":"06:55.755","Text":"That is made up of a chain of N-acetylglucosamine."},{"Start":"06:55.755 ","End":"06:58.380","Text":"Well, in glycosaminoglycans,"},{"Start":"06:58.380 ","End":"07:00.465","Text":"which is a hedge or polysaccharide,"},{"Start":"07:00.465 ","End":"07:06.605","Text":"you have this as being one component of the disaccharides."},{"Start":"07:06.605 ","End":"07:09.625","Text":"It\u0027s going to be one of the two monosaccharides,"},{"Start":"07:09.625 ","End":"07:14.355","Text":"or it may be an N-acetylgalactosamine."},{"Start":"07:14.355 ","End":"07:18.410","Text":"An N-acetylglucosamine, which means a glucose,"},{"Start":"07:18.410 ","End":"07:22.460","Text":"that one hydroxyl group that\u0027s connected to a carbon was"},{"Start":"07:22.460 ","End":"07:26.540","Text":"changed with an amine group or an N-acetylgalactosamine,"},{"Start":"07:26.540 ","End":"07:30.905","Text":"which means a galactose that had,"},{"Start":"07:30.905 ","End":"07:35.135","Text":"again a hydroxyl group on a carbon chained with an amine group."},{"Start":"07:35.135 ","End":"07:36.620","Text":"Just to remind you,"},{"Start":"07:36.620 ","End":"07:41.375","Text":"galactose and glucose are both monosaccharides."},{"Start":"07:41.375 ","End":"07:46.760","Text":"In the glycosaminoglycans, you\u0027re going to have one of the two monosaccharide units."},{"Start":"07:46.760 ","End":"07:49.310","Text":"One of the disaccharide units is always going to be"},{"Start":"07:49.310 ","End":"07:53.330","Text":"either the N-acetylglucosamine or the N-acetylgalactosamine,"},{"Start":"07:53.330 ","End":"07:59.090","Text":"meaning either the glucose or the galactose that had an amine group replaced."},{"Start":"07:59.090 ","End":"08:03.665","Text":"The other is in most cases a uronic acid."},{"Start":"08:03.665 ","End":"08:10.955","Text":"The second molecule of a disaccharide in most cases being the uronic acid."},{"Start":"08:10.955 ","End":"08:16.780","Text":"That would usually be D-glucuronic or L-iduronic acid."},{"Start":"08:16.780 ","End":"08:19.565","Text":"In other words, glycosaminoglycans,"},{"Start":"08:19.565 ","End":"08:23.584","Text":"that from now on I\u0027m just going to call GAGs for short,"},{"Start":"08:23.584 ","End":"08:29.360","Text":"are long linear polysaccharides consisting of repeating disaccharide units, i.e."},{"Start":"08:29.360 ","End":"08:30.695","Text":"two sugar units."},{"Start":"08:30.695 ","End":"08:37.920","Text":"The repeating two sugar unit consists of a uronic acid and an amino sugar."},{"Start":"08:38.300 ","End":"08:42.889","Text":"That can be either the glucosamine or the galactosamine,"},{"Start":"08:42.889 ","End":"08:45.635","Text":"with the exception of keratin,"},{"Start":"08:45.635 ","End":"08:49.810","Text":"which we will mention further in a minute where in the place of the uronic sugar,"},{"Start":"08:49.810 ","End":"08:52.365","Text":"it has a galactose."},{"Start":"08:52.365 ","End":"08:55.515","Text":"Now because GAGs are highly polar and attract water,"},{"Start":"08:55.515 ","End":"09:00.820","Text":"they\u0027re used in the body as a lubricant or shock absorber."},{"Start":"09:00.820 ","End":"09:04.540","Text":"The combination of sulfate groups and the carboxylic groups of"},{"Start":"09:04.540 ","End":"09:10.660","Text":"the uronic acid residues gives GAGs a very high density of negative charge."},{"Start":"09:10.660 ","End":"09:14.440","Text":"To minimize the repulsive forces among neighboring charged groups,"},{"Start":"09:14.440 ","End":"09:18.444","Text":"these molecules assume an extended conformation solution"},{"Start":"09:18.444 ","End":"09:22.350","Text":"because if they have a negative charge they could repel each other,"},{"Start":"09:22.350 ","End":"09:26.495","Text":"and that is how this obstacle\u0027s overcome."},{"Start":"09:26.495 ","End":"09:28.990","Text":"They minimize the repulsive forces among"},{"Start":"09:28.990 ","End":"09:34.630","Text":"neighboring charged groups by assuming an extended conformation in solution."},{"Start":"09:34.630 ","End":"09:42.810","Text":"The specific patterns of sulfated and non-sulfated sugar residues in"},{"Start":"09:42.810 ","End":"09:46.990","Text":"GAGs provide for specific recognition by a variety of"},{"Start":"09:46.990 ","End":"09:52.465","Text":"protein ligands that bind electrostatically to these molecules."},{"Start":"09:52.465 ","End":"09:58.615","Text":"These function, these patterns as a stamp"},{"Start":"09:58.615 ","End":"10:05.649","Text":"identifying the residues for protein ligands that bind to these molecules."},{"Start":"10:05.649 ","End":"10:13.810","Text":"The sulfated GAGS are attached to extracellular proteins to form proteoglycans,"},{"Start":"10:13.810 ","End":"10:17.605","Text":"which we will talk about in a later lesson."},{"Start":"10:17.605 ","End":"10:24.620","Text":"If we look again at this figure just to imprint it and to understand,"},{"Start":"10:24.620 ","End":"10:27.365","Text":"the molecules are copolymers of alternating"},{"Start":"10:27.365 ","End":"10:34.550","Text":"uronic acid and amino sugar residues with sulfate esters in any of several positions."},{"Start":"10:34.550 ","End":"10:37.520","Text":"Now you see here the links between them are different."},{"Start":"10:37.520 ","End":"10:39.720","Text":"You have Beta 1, 3, Beta 1,"},{"Start":"10:39.720 ","End":"10:42.200","Text":"3, Beta 1, 4, Alpha 1, 4."},{"Start":"10:42.200 ","End":"10:45.410","Text":"The links between them are a little different."},{"Start":"10:45.410 ","End":"10:48.134","Text":"This is 1, 2,"},{"Start":"10:48.134 ","End":"10:50.760","Text":"3 1, 2,"},{"Start":"10:50.760 ","End":"10:52.350","Text":"3, this is the one carbon,"},{"Start":"10:52.350 ","End":"10:53.550","Text":"so here\u0027s it\u0027s a Beta 1,"},{"Start":"10:53.550 ","End":"10:55.911","Text":"3 link, whereas here, 1,"},{"Start":"10:55.911 ","End":"10:56.940","Text":"2, 3, 4,"},{"Start":"10:56.940 ","End":"11:00.615","Text":"it\u0027s linked to the fourth carbon 1-4, and here,"},{"Start":"11:00.615 ","End":"11:02.640","Text":"you have also 1-4,"},{"Start":"11:02.640 ","End":"11:04.365","Text":"but it\u0027s an Alpha link,"},{"Start":"11:04.365 ","End":"11:07.545","Text":"so the glycosidic link is an Alpha link."},{"Start":"11:07.545 ","End":"11:10.820","Text":"The ionized carboxylate and sulfate groups,"},{"Start":"11:10.820 ","End":"11:14.250","Text":"which are in this pink,"},{"Start":"11:14.250 ","End":"11:17.810","Text":"give these polymers their characteristic high negative charge,"},{"Start":"11:17.810 ","End":"11:20.405","Text":"so you see the negative charge is here."},{"Start":"11:20.405 ","End":"11:27.395","Text":"Heparin contains primarily iduronic acid, heparin,"},{"Start":"11:27.395 ","End":"11:30.845","Text":"and a smaller proportion of glucuronic acid,"},{"Start":"11:30.845 ","End":"11:35.565","Text":"which is GlcA, glucuronic acid."},{"Start":"11:35.565 ","End":"11:38.885","Text":"It is generally highly sulfated."},{"Start":"11:38.885 ","End":"11:40.310","Text":"See the sulfate here,"},{"Start":"11:40.310 ","End":"11:43.160","Text":"sulfate here, here, here."},{"Start":"11:43.160 ","End":"11:44.900","Text":"You can see it indicated here,"},{"Start":"11:44.900 ","End":"11:48.490","Text":"this is the sulfated indication."},{"Start":"11:48.490 ","End":"11:53.000","Text":"It\u0027s highly sulfated and heterogeneous in length,"},{"Start":"11:53.000 ","End":"11:57.635","Text":"meaning if you see here it\u0027s usually for hyaluronate around 50,000,"},{"Start":"11:57.635 ","End":"11:59.270","Text":"for chondroitin 20-60,"},{"Start":"11:59.270 ","End":"12:02.690","Text":"that\u0027s a difference but still,"},{"Start":"12:02.690 ","End":"12:06.980","Text":"here you have about 25 but here you have 15-90."},{"Start":"12:06.980 ","End":"12:09.185","Text":"This is a huge difference,"},{"Start":"12:09.185 ","End":"12:11.795","Text":"it\u0027s very heterogeneous in its length."},{"Start":"12:11.795 ","End":"12:20.795","Text":"Heparin sulfate, which is not shown here because we have heparin versus heparan sulfate,"},{"Start":"12:20.795 ","End":"12:26.645","Text":"is similar to heparin but has a higher proportion of glucuronic acid."},{"Start":"12:26.645 ","End":"12:31.325","Text":"Basically, it has more of these and fewer sulfate groups"},{"Start":"12:31.325 ","End":"12:34.100","Text":"arranged in a less regular pattern."},{"Start":"12:34.100 ","End":"12:38.840","Text":"With this, we completed part I of heteropolysaccharides in the extracellular matrix."},{"Start":"12:38.840 ","End":"12:41.525","Text":"In this section, we became familiar with the term"},{"Start":"12:41.525 ","End":"12:46.100","Text":"extracellular matrix and glycosaminoglycans composition and structure."},{"Start":"12:46.100 ","End":"12:48.930","Text":"Meet you in part 2."}],"ID":30524},{"Watched":false,"Name":"Heteropolysaccharides - Extracellular Matrix Part 2","Duration":"7m 41s","ChapterTopicVideoID":28946,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.445","Text":"Welcome to part 2 of heteropolysaccharides of the extracellular matrix."},{"Start":"00:05.445 ","End":"00:08.880","Text":"In this section, we will further learn about"},{"Start":"00:08.880 ","End":"00:15.420","Text":"the extracellular matrix and the glycosaminoglycan hyaluronan and its variations."},{"Start":"00:15.420 ","End":"00:19.816","Text":"Let\u0027s dive in. Let\u0027s talk about some common GAGs of the ECM,"},{"Start":"00:19.816 ","End":"00:25.610","Text":"the extracellular matrix, starting with the gag hyaluronic acid,"},{"Start":"00:25.610 ","End":"00:32.150","Text":"also called hyaluronan, which contains alternating residues of D-glucuronic acid and"},{"Start":"00:32.150 ","End":"00:36.590","Text":"N-acetylglucosamine and forms a clear, highly viscous solution"},{"Start":"00:36.590 ","End":"00:39.440","Text":"that serves as a lubricant in joints."},{"Start":"00:39.440 ","End":"00:42.005","Text":"The hyaluronic acid, in the figure,"},{"Start":"00:42.005 ","End":"00:44.270","Text":"what we actually see is hyaluronate."},{"Start":"00:44.270 ","End":"00:51.140","Text":"Hyaluronate is at physiological pH and it\u0027s just a little bit different."},{"Start":"00:51.140 ","End":"00:55.175","Text":"Now, hyaluronic acid, as just hyaluronate,"},{"Start":"00:55.175 ","End":"01:00.020","Text":"contains up to 50,000 repeats of the basic disaccharide unit."},{"Start":"01:00.020 ","End":"01:03.290","Text":"Hyaluronates have molecular weights greater than 1"},{"Start":"01:03.290 ","End":"01:07.819","Text":"million and it forms a clear highly viscous solution,"},{"Start":"01:07.819 ","End":"01:11.300","Text":"as mentioned, that serve as a lubricant to joints and gives"},{"Start":"01:11.300 ","End":"01:15.620","Text":"the vitreous humor of the vertebrate eye its jelly-like consistency."},{"Start":"01:15.620 ","End":"01:22.485","Text":"Now, hyaluronic acid comes from the Greek word hyalos, which means glass."},{"Start":"01:22.485 ","End":"01:26.370","Text":"Hyaluronates can have a glassy or translucent appearance,"},{"Start":"01:26.370 ","End":"01:29.285","Text":"and that\u0027s why when it was identified,"},{"Start":"01:29.285 ","End":"01:34.130","Text":"it was termed hyaluronic acid, hyaluronan or hyaluronate."},{"Start":"01:34.130 ","End":"01:38.255","Text":"Now, all these endings are just different arrangements"},{"Start":"01:38.255 ","End":"01:42.575","Text":"of the molecules with different conditions."},{"Start":"01:42.575 ","End":"01:50.120","Text":"Hyaluronate is also an essential component of the ECM of cartilage"},{"Start":"01:50.120 ","End":"01:54.755","Text":"and tendons to which it contributes tensile strength"},{"Start":"01:54.755 ","End":"01:56.450","Text":"and elasticity as a result of"},{"Start":"01:56.450 ","End":"01:59.795","Text":"its strong interactions with other components of the matrix."},{"Start":"01:59.795 ","End":"02:01.835","Text":"It gives flexibility,"},{"Start":"02:01.835 ","End":"02:04.935","Text":"yet at the same time, the strength."},{"Start":"02:04.935 ","End":"02:08.420","Text":"It needs that elasticity for cartilage and"},{"Start":"02:08.420 ","End":"02:13.445","Text":"tendons so that they can have give when it\u0027s pulled and moved,"},{"Start":"02:13.445 ","End":"02:19.070","Text":"because they connect and sit between bones, etc."},{"Start":"02:19.070 ","End":"02:27.130","Text":"We have these as being lubricants in joints and in cartilage and tendons."},{"Start":"02:27.130 ","End":"02:29.624","Text":"Let\u0027s talk about hyaluronidase,"},{"Start":"02:29.624 ","End":"02:34.045","Text":"an enzyme because we have a suffix ase."},{"Start":"02:34.045 ","End":"02:37.340","Text":"An enzyme secreted by some pathogenic bacteria that can"},{"Start":"02:37.340 ","End":"02:41.770","Text":"hydrolyze the glycosidic linkage of hyaluronate."},{"Start":"02:41.770 ","End":"02:48.695","Text":"This renders these tissues more susceptible to bacterial invasion."},{"Start":"02:48.695 ","End":"02:54.830","Text":"Yet these are generally more internal and protected by skin layers and whatnot."},{"Start":"02:54.830 ","End":"02:56.774","Text":"Now in many organisms,"},{"Start":"02:56.774 ","End":"03:02.515","Text":"a similar enzyme in sperm hydrolyzes an outer glycosaminoglycan coat,"},{"Start":"03:02.515 ","End":"03:05.135","Text":"an outer GAG coat, around the ovum,"},{"Start":"03:05.135 ","End":"03:11.765","Text":"allowing sperm penetration, that is what allows the sperm to penetrate the egg."},{"Start":"03:11.765 ","End":"03:16.910","Text":"Other GAGs differ from hyaluronate in 3 respects."},{"Start":"03:16.910 ","End":"03:23.725","Text":"1, they are generally much shorter polymers versus the 50,000 repeating units."},{"Start":"03:23.725 ","End":"03:29.565","Text":"2, they\u0027re covalently linked to specific proteins,"},{"Start":"03:29.565 ","End":"03:32.715","Text":"proteoglycans, and 3,"},{"Start":"03:32.715 ","End":"03:38.875","Text":"one or both monomeric units differ from those of hyaluronan."},{"Start":"03:38.875 ","End":"03:40.610","Text":"Let\u0027s talk about these."},{"Start":"03:40.610 ","End":"03:42.095","Text":"We saw them in the figure."},{"Start":"03:42.095 ","End":"03:48.920","Text":"We have chondroitin sulfate from the Greek word chondros, which means cartilage."},{"Start":"03:48.920 ","End":"03:52.594","Text":"This contributes to the malleable strength of cartilage,"},{"Start":"03:52.594 ","End":"03:55.835","Text":"tendons, ligaments, and the walls of the aorta."},{"Start":"03:55.835 ","End":"04:00.020","Text":"This is what allows blood in and out of our heart."},{"Start":"04:00.020 ","End":"04:04.745","Text":"We then have dermatan sulfate from the Greek word derma,"},{"Start":"04:04.745 ","End":"04:08.495","Text":"skin, like dermis, epidermis."},{"Start":"04:08.495 ","End":"04:11.780","Text":"This contributes to the pliability of skin"},{"Start":"04:11.780 ","End":"04:15.604","Text":"and is also present in blood vessels and heart valves."},{"Start":"04:15.604 ","End":"04:21.835","Text":"Again, like skin, you want it to not be leaky so that blood doesn\u0027t go in and out,"},{"Start":"04:21.835 ","End":"04:27.050","Text":"yet you want it to be flexible, pliable, malleable."},{"Start":"04:27.050 ","End":"04:30.900","Text":"In this polymer, many of the glucoronate,"},{"Start":"04:30.900 ","End":"04:34.430","Text":"GlcA residues present in chondroitin sulfate are"},{"Start":"04:34.430 ","End":"04:39.450","Text":"replaced by their epimer, iduronate, IdoA."},{"Start":"04:40.460 ","End":"04:46.355","Text":"You have these residues, iduronate and sulfate,"},{"Start":"04:46.355 ","End":"04:52.940","Text":"which the addition of this is what separates it from the chondroitin sulfate."},{"Start":"04:52.940 ","End":"04:55.205","Text":"Next we have keratan sulfate,"},{"Start":"04:55.205 ","End":"04:57.980","Text":"and this is from the Greek word keras, horn."},{"Start":"04:57.980 ","End":"05:01.025","Text":"They have no uronic acid,"},{"Start":"05:01.025 ","End":"05:03.650","Text":"and their sulfate content is variable."},{"Start":"05:03.650 ","End":"05:07.700","Text":"The sulfate that is added is not consistent."},{"Start":"05:07.700 ","End":"05:11.425","Text":"They are present in cornea, cartilage,"},{"Start":"05:11.425 ","End":"05:15.560","Text":"bone and a variety of horny structures."},{"Start":"05:15.560 ","End":"05:19.325","Text":"Horny as in horns."},{"Start":"05:19.325 ","End":"05:25.189","Text":"Formed of dead cells: horn, hair, hoofs,"},{"Start":"05:25.189 ","End":"05:31.790","Text":"nails and claws, and therefore the term keratin sulfate from keras, horn."},{"Start":"05:31.790 ","End":"05:37.910","Text":"We also know that the term keratin in our hair, nails, etc."},{"Start":"05:37.910 ","End":"05:42.935","Text":"Next we have the GAG, heparin sulfate."},{"Start":"05:42.935 ","End":"05:46.384","Text":"Hepar comes from Greek."},{"Start":"05:46.384 ","End":"05:47.809","Text":"It means liver."},{"Start":"05:47.809 ","End":"05:52.220","Text":"It is produced by all animal cells and contains"},{"Start":"05:52.220 ","End":"05:57.455","Text":"variable arrangements of sulfated and non sulfated sugars."},{"Start":"05:57.455 ","End":"06:02.179","Text":"The sulfated segments of the chain allow it to interact with a large number of proteins,"},{"Start":"06:02.179 ","End":"06:05.285","Text":"including growth factors and ECM components,"},{"Start":"06:05.285 ","End":"06:08.885","Text":"as well as various enzymes and factors present in plasma."},{"Start":"06:08.885 ","End":"06:13.640","Text":"Heparin is a highly sulfated intracellular form of"},{"Start":"06:13.640 ","End":"06:19.134","Text":"heparin sulfate produced primarily by mast cells,"},{"Start":"06:19.134 ","End":"06:24.395","Text":"a type of leukocyte or immune cell that is generally found in the blood."},{"Start":"06:24.395 ","End":"06:29.210","Text":"It is a natural anticoagulant made in mast cells and released into"},{"Start":"06:29.210 ","End":"06:36.085","Text":"the blood where it inhibits blood coagulation by binding to the protein, antithrombin."},{"Start":"06:36.085 ","End":"06:42.749","Text":"Heparin binding causes antithrombin to bind to and inhibit thrombin,"},{"Start":"06:42.749 ","End":"06:45.155","Text":"a protease essential to blood clotting."},{"Start":"06:45.155 ","End":"06:48.140","Text":"The interaction is strongly electrostatic."},{"Start":"06:48.140 ","End":"06:50.510","Text":"In other words, it inhibits coagulation of"},{"Start":"06:50.510 ","End":"06:52.910","Text":"blood through its capacity to bind the protease inhibitor"},{"Start":"06:52.910 ","End":"06:58.520","Text":"anti-thrombin because we don\u0027t want blood to clot when it is flowing through a body."},{"Start":"06:58.520 ","End":"07:05.540","Text":"Purified heparin is routinely used as a therapeutic agent added to"},{"Start":"07:05.540 ","End":"07:08.990","Text":"blood samples obtained for clinical analysis and"},{"Start":"07:08.990 ","End":"07:13.650","Text":"to blood donated for transfusion to prevent clotting."},{"Start":"07:13.870 ","End":"07:22.525","Text":"Heparin has the highest negative charge density of any known biological macromolecule."},{"Start":"07:22.525 ","End":"07:25.940","Text":"With this, we completed heteropolysaccharides of"},{"Start":"07:25.940 ","End":"07:30.770","Text":"the extracellular matrix within the topic of polysaccharides in this section."},{"Start":"07:30.770 ","End":"07:35.000","Text":"By now, you should understand and know the term"},{"Start":"07:35.000 ","End":"07:41.459","Text":"the extracellular matrix and glycosaminoglycans and its various types."}],"ID":30525},{"Watched":false,"Name":"Exercise 16","Duration":"47s","ChapterTopicVideoID":28947,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:02.610","Text":"Welcome to an exercise covering the topic of"},{"Start":"00:02.610 ","End":"00:06.555","Text":"heteropolysaccharides in the extracellular matrix, the ECM."},{"Start":"00:06.555 ","End":"00:10.545","Text":"What is the extracellular matrix and what is it composed of?"},{"Start":"00:10.545 ","End":"00:13.335","Text":"The extracellular matrix, the ECM,"},{"Start":"00:13.335 ","End":"00:15.320","Text":"is a gel-like material that fills"},{"Start":"00:15.320 ","End":"00:19.370","Text":"the extracellular space and the tissues of multicellular animals."},{"Start":"00:19.370 ","End":"00:25.430","Text":"It comes between the tissues and it\u0027s also called ground substance."},{"Start":"00:25.430 ","End":"00:28.400","Text":"It holds the cells together and allows the diffusion of"},{"Start":"00:28.400 ","End":"00:31.175","Text":"nutrients and oxygen to individual cells."},{"Start":"00:31.175 ","End":"00:35.405","Text":"It\u0027s what allows the movement of these things between cells."},{"Start":"00:35.405 ","End":"00:37.940","Text":"The extracellular matrix is composed of"},{"Start":"00:37.940 ","End":"00:42.560","Text":"interlinked tetrapolysaccharides and fibrous proteins such as collagen,"},{"Start":"00:42.560 ","End":"00:45.900","Text":"elastin, fibronectin, and laminin."}],"ID":30526},{"Watched":false,"Name":"Exercise 17","Duration":"3m 16s","ChapterTopicVideoID":28948,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.230 ","End":"00:06.810","Text":"Let\u0027s conquer another exercise within heteropolysaccharides extracellular matrix."},{"Start":"00:06.810 ","End":"00:08.580","Text":"What is the general name for"},{"Start":"00:08.580 ","End":"00:12.210","Text":"the heteropolysaccharides that make up the extracellular matrix?"},{"Start":"00:12.210 ","End":"00:14.730","Text":"Mentioned its characteristics."},{"Start":"00:14.730 ","End":"00:16.710","Text":"The heteropolysaccharides that make up"},{"Start":"00:16.710 ","End":"00:21.255","Text":"the extracellular matrix are called glycosaminoglycans."},{"Start":"00:21.255 ","End":"00:24.480","Text":"Say this quick, 3 times the glycosaminoglycans."},{"Start":"00:24.480 ","End":"00:25.980","Text":"I don\u0027t want to say it a third time,"},{"Start":"00:25.980 ","End":"00:31.155","Text":"therefore, we\u0027re going to call them Gags from here on."},{"Start":"00:31.155 ","End":"00:36.755","Text":"They are a family of linear polymers composed of repeating disaccharide units."},{"Start":"00:36.755 ","End":"00:39.695","Text":"1 of the 2 monosaccharides is always"},{"Start":"00:39.695 ","End":"00:43.945","Text":"either N-acetylglucosamine or an N-acetylgalactosamine."},{"Start":"00:43.945 ","End":"00:45.320","Text":"Do you remember what these are?"},{"Start":"00:45.320 ","End":"00:53.195","Text":"These are glucose molecules or galactose molecules that actually have a hydroxyl group"},{"Start":"00:53.195 ","End":"01:03.005","Text":"replaced with an amine group and the other is in most cases, a uronic acid."},{"Start":"01:03.005 ","End":"01:06.890","Text":"They are made of repeating disaccharide units with 1 of"},{"Start":"01:06.890 ","End":"01:11.900","Text":"the 2 monosaccharides always be either N-acetylglucosamine or the N-acetylgalactosamine,"},{"Start":"01:11.900 ","End":"01:14.480","Text":"meaning the derivatives of glucose or galactose."},{"Start":"01:14.480 ","End":"01:17.640","Text":"The second is in most cases,"},{"Start":"01:17.640 ","End":"01:20.675","Text":"a uronic acid we mentioned an exception on this."},{"Start":"01:20.675 ","End":"01:26.100","Text":"Now it is usually a D-glucuronic or an uronic acid."},{"Start":"01:26.100 ","End":"01:28.820","Text":"In other words, gags for"},{"Start":"01:28.820 ","End":"01:33.665","Text":"short or long linear polysaccharides consisting of repeating disaccharide units,"},{"Start":"01:33.665 ","End":"01:37.655","Text":"i2 sugar units with a repeating 2 sugar unit consisting of"},{"Start":"01:37.655 ","End":"01:42.425","Text":"a uronic sugar and an amino sugar with exception of keratin,"},{"Start":"01:42.425 ","End":"01:45.800","Text":"which we briefly covered in the lesson,"},{"Start":"01:45.800 ","End":"01:49.250","Text":"we\u0027re in the place of the uronic sugar, it has galactose."},{"Start":"01:49.250 ","End":"01:51.620","Text":"Now because gags are highly polar and attract water,"},{"Start":"01:51.620 ","End":"01:56.405","Text":"they\u0027re used in the body as a lubricant or shock absorber and so just to remind you,"},{"Start":"01:56.405 ","End":"02:02.675","Text":"the disaccharides are made of a uronic sugar in almost all cases,"},{"Start":"02:02.675 ","End":"02:05.645","Text":"except which, if you remember,"},{"Start":"02:05.645 ","End":"02:08.345","Text":"that comes from the term horn,"},{"Start":"02:08.345 ","End":"02:10.895","Text":"which is what makes hair and horns,"},{"Start":"02:10.895 ","End":"02:14.555","Text":"cell tissues and amino sugar,"},{"Start":"02:14.555 ","End":"02:18.095","Text":"which would be 1 of these 2."},{"Start":"02:18.095 ","End":"02:22.790","Text":"Now, the combination of sulfate groups and the carboxylic group,"},{"Start":"02:22.790 ","End":"02:29.839","Text":"so the uronic acid residues gives gags a very high density of negative charge."},{"Start":"02:29.839 ","End":"02:34.040","Text":"Now to minimize the repulsive forces among the neighboring charged groups,"},{"Start":"02:34.040 ","End":"02:36.950","Text":"these molecules assume an extended conformation"},{"Start":"02:36.950 ","End":"02:40.680","Text":"and solutions so they spread and are long."},{"Start":"02:41.360 ","End":"02:45.960","Text":"With that, we gave the name for"},{"Start":"02:45.960 ","End":"02:49.985","Text":"heteropolysaccharides that make up the ECM extracellular matrix."},{"Start":"02:49.985 ","End":"02:53.780","Text":"These are glycosaminoglycans, gags and we"},{"Start":"02:53.780 ","End":"02:56.600","Text":"mentioned their characteristic linear polymers"},{"Start":"02:56.600 ","End":"02:58.565","Text":"can composed of repeating disaccharide units,"},{"Start":"02:58.565 ","End":"03:07.205","Text":"with a disaccharide units being 1 and amino sugar and 1 ironic acid except in exception"},{"Start":"03:07.205 ","End":"03:10.850","Text":"of keratin and the combination of the sulfate groups and"},{"Start":"03:10.850 ","End":"03:17.100","Text":"the carboxylic groups give these a high density of negative charge."}],"ID":30527},{"Watched":false,"Name":"Exercise 18","Duration":"2m 3s","ChapterTopicVideoID":28949,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.035","Text":"You still with me because we have another exercise covering."},{"Start":"00:04.035 ","End":"00:07.544","Text":"Heteropolysaccharides of extracellular matrix."},{"Start":"00:07.544 ","End":"00:10.470","Text":"Define hyaluronan."},{"Start":"00:10.470 ","End":"00:13.080","Text":"Hyaluronan is the glycosaminoglycan,"},{"Start":"00:13.080 ","End":"00:15.765","Text":"the GAG, hyaluronic acid."},{"Start":"00:15.765 ","End":"00:19.680","Text":"Hyaluronic acid comes from the Greek word hyalos, glass."},{"Start":"00:19.680 ","End":"00:21.615","Text":"This is because, hyaluronic can have"},{"Start":"00:21.615 ","End":"00:24.405","Text":"a glassy or translucent appearance through gel like,"},{"Start":"00:24.405 ","End":"00:26.385","Text":"they\u0027re viscous and queer."},{"Start":"00:26.385 ","End":"00:32.429","Text":"It contains alternating residues of D-glucuronic acid and N-acetylglucosamine,"},{"Start":"00:32.429 ","End":"00:40.190","Text":"so you have alternating residues of the glucuronic acid and acetyl glucosamine."},{"Start":"00:40.190 ","End":"00:44.870","Text":"It has up to 50,000 repeats of the basic disaccharide unit."},{"Start":"00:44.870 ","End":"00:47.000","Text":"This is 1 unit, this is 2 units,"},{"Start":"00:47.000 ","End":"00:50.910","Text":"so 2 monosaccharides make up a disaccharide."},{"Start":"00:51.500 ","End":"01:00.070","Text":"Hyaluronic acid is made up of up to 50,000 repeats of this disaccharide is huge."},{"Start":"01:00.070 ","End":"01:04.805","Text":"Hyaluronate, have molecular weights greater than 1 million,"},{"Start":"01:04.805 ","End":"01:12.085","Text":"which makes sense with being that they have up to 50,000 disaccharide units making them."},{"Start":"01:12.085 ","End":"01:13.460","Text":"It forms a clear,"},{"Start":"01:13.460 ","End":"01:17.840","Text":"highly viscous solution that serves as a lubricant in joints."},{"Start":"01:17.840 ","End":"01:20.720","Text":"It gives the vitreous humor of the vertebrate eye."},{"Start":"01:20.720 ","End":"01:22.670","Text":"It\u0027s jelly-like consistency."},{"Start":"01:22.670 ","End":"01:27.160","Text":"It gives the eye that jell-like consistency within the eyeball."},{"Start":"01:27.160 ","End":"01:31.895","Text":"Hyaluronate, is also an essential component of the ECM of cartilage"},{"Start":"01:31.895 ","End":"01:36.470","Text":"and tendons to which it contributes tensile strength and elasticity,"},{"Start":"01:36.470 ","End":"01:39.650","Text":"as a result of its strong interactions with other components of the matrix."},{"Start":"01:39.650 ","End":"01:42.500","Text":"Meaning, you need these to be super-strong yet,"},{"Start":"01:42.500 ","End":"01:44.645","Text":"to be malleable, to be elastic."},{"Start":"01:44.645 ","End":"01:51.005","Text":"They can push and pull between the bones and through movement and through muscle."},{"Start":"01:51.005 ","End":"01:55.010","Text":"Hyaluronate is this essential component for"},{"Start":"01:55.010 ","End":"01:59.855","Text":"the ECM of these cartilage and tendencies types of tissue."},{"Start":"01:59.855 ","End":"02:03.390","Text":"With that, we defined hyaluronan."}],"ID":30528},{"Watched":false,"Name":"Exercise 19","Duration":"3m 14s","ChapterTopicVideoID":28950,"CourseChapterTopicPlaylistID":293020,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:06.720","Text":"Hope you\u0027re ready for another exercise on heteropolysaccharides, extracellular matrix."},{"Start":"00:06.720 ","End":"00:12.120","Text":"Name and characterize the other 4 GAGs that differ from hyaluronic acid."},{"Start":"00:12.120 ","End":"00:17.130","Text":"We mentioned chondroitin sulfate comes from the Greek word Chondros, cartilage,"},{"Start":"00:17.130 ","End":"00:21.195","Text":"and it contributes to the malleable strength of cartilage tendons, ligaments,"},{"Start":"00:21.195 ","End":"00:23.478","Text":"and the walls of the aorta,"},{"Start":"00:23.478 ","End":"00:25.845","Text":"that is important for the heart function."},{"Start":"00:25.845 ","End":"00:30.695","Text":"We mentioned dermatan sulfate from the Greek word Derma, skin."},{"Start":"00:30.695 ","End":"00:33.260","Text":"It contributes to the pliability of skin and is"},{"Start":"00:33.260 ","End":"00:36.760","Text":"also present in blood vessels and heart valves."},{"Start":"00:36.760 ","End":"00:41.210","Text":"In this polymer, many of the gluconate residues present in"},{"Start":"00:41.210 ","End":"00:45.230","Text":"chondroitin sulfate are replaced by their epimer hyaluronates."},{"Start":"00:45.230 ","End":"00:49.265","Text":"Instead of GLCA,"},{"Start":"00:49.265 ","End":"00:55.655","Text":"you will see some are replaced with IdoA."},{"Start":"00:55.655 ","End":"00:58.070","Text":"We talked about the cartilage."},{"Start":"00:58.070 ","End":"01:01.640","Text":"We talked about skin."},{"Start":"01:01.640 ","End":"01:02.990","Text":"What else did we talk about?"},{"Start":"01:02.990 ","End":"01:05.480","Text":"Remember, we talked about 2 other things."},{"Start":"01:05.480 ","End":"01:09.455","Text":"One was of the dead skins."},{"Start":"01:09.455 ","End":"01:12.845","Text":"The horns, you have keratan sulfate,"},{"Start":"01:12.845 ","End":"01:15.125","Text":"Greek word Keras, horn."},{"Start":"01:15.125 ","End":"01:22.790","Text":"They have no uronic acid and this is the exception to the disaccharides that make GAGs."},{"Start":"01:22.790 ","End":"01:28.370","Text":"Remember, because all the other ones are made of uronic acid."},{"Start":"01:28.370 ","End":"01:32.975","Text":"Basically uronic sugar and then amino sugar."},{"Start":"01:32.975 ","End":"01:34.490","Text":"A sugar amine."},{"Start":"01:34.490 ","End":"01:37.040","Text":"Keratin is the one exception that has"},{"Start":"01:37.040 ","End":"01:40.700","Text":"no uronic acid and their sulfate content is variable."},{"Start":"01:40.700 ","End":"01:46.085","Text":"How much sulfate is on the molecules is different."},{"Start":"01:46.085 ","End":"01:48.650","Text":"They are present in cornea,"},{"Start":"01:48.650 ","End":"01:51.770","Text":"cartilage, bone and a variety of horny structures."},{"Start":"01:51.770 ","End":"01:53.690","Text":"Again, horny, as in horned,"},{"Start":"01:53.690 ","End":"01:56.540","Text":"formed of dead cells: horn hairs,"},{"Start":"01:56.540 ","End":"01:58.745","Text":"hoofs, nails, and claws."},{"Start":"01:58.745 ","End":"02:04.010","Text":"Last but not least of what we mentioned is heparan sulfate."},{"Start":"02:04.010 ","End":"02:06.995","Text":"That\u0027s from the Greek word Hepar, liver."},{"Start":"02:06.995 ","End":"02:10.685","Text":"Heparan sulfate is produced by all animal cells and contains"},{"Start":"02:10.685 ","End":"02:15.590","Text":"variable arrangements of sulfated and non sulfated sugars."},{"Start":"02:15.590 ","End":"02:20.850","Text":"It is highly present also in liver cells."},{"Start":"02:20.850 ","End":"02:28.040","Text":"These are the 4 GAGs that differ from hyaluronate with their characteristics."},{"Start":"02:28.040 ","End":"02:31.460","Text":"Chondroitin sulfate found in the cartilage,"},{"Start":"02:31.460 ","End":"02:33.680","Text":"in tendons and ligaments."},{"Start":"02:33.680 ","End":"02:38.030","Text":"We had dermatan sulfate in Derma."},{"Start":"02:38.030 ","End":"02:39.810","Text":"It is in the skin,"},{"Start":"02:39.810 ","End":"02:42.065","Text":"it contributes to the pliability of skin."},{"Start":"02:42.065 ","End":"02:44.135","Text":"We have keratin sulfate."},{"Start":"02:44.135 ","End":"02:46.325","Text":"It is within cornea,"},{"Start":"02:46.325 ","End":"02:52.920","Text":"cartilage bone and a variety of structures like hair, horn, nails, etc."},{"Start":"02:52.920 ","End":"03:00.340","Text":"Then we have heparan sulfate found in all animal cells."},{"Start":"03:00.340 ","End":"03:05.690","Text":"We then of course have what we compared it to, hyaluronic acid,"},{"Start":"03:05.690 ","End":"03:13.440","Text":"which is found as the lubricant in joints and in the eyeballs."}],"ID":30529}],"Thumbnail":null,"ID":293020},{"Name":"Glycoconjugates","TopicPlaylistFirstVideoID":0,"Duration":null,"Videos":[{"Watched":false,"Name":"Introduction to Glycoconjugates","Duration":"9m 46s","ChapterTopicVideoID":28980,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:01.785","Text":"Hi, there, we\u0027re back."},{"Start":"00:01.785 ","End":"00:05.250","Text":"We\u0027re going to start with an introduction to glycoconjugates."},{"Start":"00:05.250 ","End":"00:10.215","Text":"In this section, we will learn about the glycoconjugates definition,"},{"Start":"00:10.215 ","End":"00:11.595","Text":"what this actually means,"},{"Start":"00:11.595 ","End":"00:14.700","Text":"and the different types of glycoconjugates."},{"Start":"00:14.700 ","End":"00:17.895","Text":"Glycoconjugates, there are 3 types."},{"Start":"00:17.895 ","End":"00:20.565","Text":"We have proteoglycans, glycoproteins,"},{"Start":"00:20.565 ","End":"00:23.730","Text":"and glycolipids, we\u0027re going to talk about these 3 types."},{"Start":"00:23.730 ","End":"00:26.625","Text":"Thus far we\u0027ve talked about carbohydrates,"},{"Start":"00:26.625 ","End":"00:30.405","Text":"mentioning the different types, the size classifications,"},{"Start":"00:30.405 ","End":"00:37.080","Text":"as can be seen in this figure where we have monosaccharides that\u0027s a 1 sugar molecule,"},{"Start":"00:37.080 ","End":"00:39.060","Text":"disaccharides 2 sugar molecules,"},{"Start":"00:39.060 ","End":"00:41.280","Text":"oligosaccharides 2-10 sugar molecules,"},{"Start":"00:41.280 ","End":"00:43.250","Text":"and polysaccharides the biggest 1,"},{"Start":"00:43.250 ","End":"00:45.268","Text":"10 or more sugar molecules,"},{"Start":"00:45.268 ","End":"00:48.595","Text":"we also introduced examples of each."},{"Start":"00:48.595 ","End":"00:51.320","Text":"Further, within polysaccharides,"},{"Start":"00:51.320 ","End":"00:55.055","Text":"we also talked about homopolysaccharides and heteropolysaccharides,"},{"Start":"00:55.055 ","End":"00:57.875","Text":"where the distinction is the type of saccharides that make"},{"Start":"00:57.875 ","End":"01:00.769","Text":"up the polysaccharide\u0027s chains."},{"Start":"01:00.769 ","End":"01:04.925","Text":"If it is made of the same monomer repeating itself,"},{"Start":"01:04.925 ","End":"01:07.385","Text":"that is a homopolysaccharide."},{"Start":"01:07.385 ","End":"01:10.205","Text":"If it is made up of a mixture of monosaccharides,"},{"Start":"01:10.205 ","End":"01:13.370","Text":"even if it is a chain of repeating disaccharides,"},{"Start":"01:13.370 ","End":"01:18.180","Text":"this is considered a heteropolysaccharide."},{"Start":"01:18.180 ","End":"01:20.630","Text":"Now, we\u0027re going to move to talk about"},{"Start":"01:20.630 ","End":"01:25.847","Text":"a different mixed molecule altogether, the glycoconjugates."},{"Start":"01:25.847 ","End":"01:28.280","Text":"In addition to the important roles that we already"},{"Start":"01:28.280 ","End":"01:31.520","Text":"introduced in previous lessons, as stored fuels,"},{"Start":"01:31.520 ","End":"01:33.780","Text":"such as starch with the 2 forms,"},{"Start":"01:33.780 ","End":"01:35.355","Text":"amylose and amylopectin,"},{"Start":"01:35.355 ","End":"01:37.800","Text":"or glycogen as seen here."},{"Start":"01:37.800 ","End":"01:39.435","Text":"These would be our starches,"},{"Start":"01:39.435 ","End":"01:42.120","Text":"starch is serving roles in plants."},{"Start":"01:42.120 ","End":"01:48.255","Text":"Glycogen serving as fuel in animals and dextrin,"},{"Start":"01:48.255 ","End":"01:50.085","Text":"which is in bacteria,"},{"Start":"01:50.085 ","End":"01:55.875","Text":"and as structural materials such as cellulose,"},{"Start":"01:55.875 ","End":"01:59.040","Text":"chitin, and peptidoglycans."},{"Start":"01:59.040 ","End":"02:06.305","Text":"Polysaccharides and oligosaccharides can also play a role as information carriers,"},{"Start":"02:06.305 ","End":"02:12.440","Text":"meaning they serve as destination labels for some proteins and as mediators of"},{"Start":"02:12.440 ","End":"02:16.190","Text":"specific cell-cell interactions and interactions"},{"Start":"02:16.190 ","End":"02:20.210","Text":"between cells and the extracellular matrix,"},{"Start":"02:20.210 ","End":"02:22.640","Text":"which we introduced in the previous lesson."},{"Start":"02:22.640 ","End":"02:29.375","Text":"Specific carbohydrate-containing molecules act in cell-cell recognition and adhesion,"},{"Start":"02:29.375 ","End":"02:33.065","Text":"cell migration during development, blood clotting,"},{"Start":"02:33.065 ","End":"02:34.280","Text":"the immune response,"},{"Start":"02:34.280 ","End":"02:38.885","Text":"and wound healing to name but a few of their many roles."},{"Start":"02:38.885 ","End":"02:41.690","Text":"In most of these cases,"},{"Start":"02:41.690 ","End":"02:45.590","Text":"the informational carbohydrate is covalently joined to"},{"Start":"02:45.590 ","End":"02:52.095","Text":"a protein or a lipid to form a glycoconjugate."},{"Start":"02:52.095 ","End":"02:53.565","Text":"The word conjugate,"},{"Start":"02:53.565 ","End":"02:55.110","Text":"like a conjugational visit,"},{"Start":"02:55.110 ","End":"03:02.545","Text":"this means joining and the glycoconjugate is the biologically active molecule."},{"Start":"03:02.545 ","End":"03:08.390","Text":"Let\u0027s talk about 1 of the 3 types of glycoconjugates mentioned."},{"Start":"03:08.390 ","End":"03:09.920","Text":"Proteoglycans."},{"Start":"03:09.920 ","End":"03:12.920","Text":"Proteoglycans are macromolecules, remember big,"},{"Start":"03:12.920 ","End":"03:19.920","Text":"of a cell surface of the extracellular matrix in which 1 or more glycosaminoglycan,"},{"Start":"03:19.920 ","End":"03:25.680","Text":"remember these are our GAGs in which"},{"Start":"03:25.680 ","End":"03:34.585","Text":"1 or more GAG chains are joined covalently to a membrane protein or a secreted protein."},{"Start":"03:34.585 ","End":"03:36.785","Text":"A reminder from previous lessons,"},{"Start":"03:36.785 ","End":"03:41.420","Text":"glycosaminoglycans are extracellular heteropolysaccharides in"},{"Start":"03:41.420 ","End":"03:46.760","Text":"which 1 of the 2 monosaccharide units is a uronic acid."},{"Start":"03:46.760 ","End":"03:55.125","Text":"GAGs are heteropolysaccharides in which 1 of the 2 monosaccharide units is"},{"Start":"03:55.125 ","End":"04:03.835","Text":"a uronic acid and the other is an N-acetylated amino sugar."},{"Start":"04:03.835 ","End":"04:07.540","Text":"Sulfate esters on some of the hydroxyl groups give these"},{"Start":"04:07.540 ","End":"04:11.155","Text":"polymers a high density of negative charge,"},{"Start":"04:11.155 ","End":"04:14.095","Text":"forcing them to assume extended conformations."},{"Start":"04:14.095 ","End":"04:17.410","Text":"These polymers, and we mentioned hyaluronate,"},{"Start":"04:17.410 ","End":"04:21.790","Text":"chondroitin sulfate, dermatomes sulfate, keratan sulfate,"},{"Start":"04:21.790 ","End":"04:24.755","Text":"and heparin provide viscosity,"},{"Start":"04:24.755 ","End":"04:30.445","Text":"adhesiveness, and tensile malleable strength to the extracellular matrix."},{"Start":"04:30.445 ","End":"04:34.885","Text":"We mentioned hyaluronate, chondroitin sulfate,"},{"Start":"04:34.885 ","End":"04:41.495","Text":"dermatomes sulfate, keratan sulfate, etc."},{"Start":"04:41.495 ","End":"04:44.705","Text":"The glycosaminoglycan, moite,"},{"Start":"04:44.705 ","End":"04:51.560","Text":"commonly forms the greater fraction by mass of the proteoglycan molecule that"},{"Start":"04:51.560 ","End":"04:59.210","Text":"dominates the structure and is often the main site of biological activity."},{"Start":"04:59.210 ","End":"05:07.760","Text":"The GAG moite of the proteoglycan is the more substantial fraction by"},{"Start":"05:07.760 ","End":"05:15.994","Text":"mass that dominates the structure and is often where the biological activity occurs."},{"Start":"05:15.994 ","End":"05:21.320","Text":"Proteoglycans are major components of connective tissues such as cartilage,"},{"Start":"05:21.320 ","End":"05:25.040","Text":"in which there are many non-covalent interactions with"},{"Start":"05:25.040 ","End":"05:29.150","Text":"other proteoglycans proteins and glycosaminoglycans, GAGs,"},{"Start":"05:29.150 ","End":"05:31.970","Text":"provide strength and flexibility,"},{"Start":"05:31.970 ","End":"05:35.810","Text":"which is super-important for the connective tissue because if we are"},{"Start":"05:35.810 ","End":"05:39.920","Text":"connecting between 2 hard bones"},{"Start":"05:39.920 ","End":"05:48.050","Text":"or 2 hard elements having flexibility and malleability gives flexibility of movement."},{"Start":"05:48.050 ","End":"05:51.140","Text":"Glycoproteins have 1 or several oligosaccharides of"},{"Start":"05:51.140 ","End":"05:55.265","Text":"varying complexity joined covalently to a protein."},{"Start":"05:55.265 ","End":"05:58.850","Text":"They\u0027re found on the outer face of the plasma membrane"},{"Start":"05:58.850 ","End":"06:04.290","Text":"in the extracellular matrix and in the blood."},{"Start":"06:04.340 ","End":"06:06.860","Text":"This is a cell membrane."},{"Start":"06:06.860 ","End":"06:12.005","Text":"The extracellular matrix is what is outside of the cell,"},{"Start":"06:12.005 ","End":"06:16.850","Text":"this is inside the cell and this is outside of the cell,"},{"Start":"06:16.850 ","End":"06:17.987","Text":"the extracellular matrix,"},{"Start":"06:17.987 ","End":"06:20.555","Text":"this would be the membrane of the cell,"},{"Start":"06:20.555 ","End":"06:23.130","Text":"this is the inside of the cell."},{"Start":"06:23.130 ","End":"06:25.417","Text":"You see the glycoproteins,"},{"Start":"06:25.417 ","End":"06:32.240","Text":"the protein of the membrane and the GAG that is attached to that membrane protein."},{"Start":"06:32.240 ","End":"06:38.390","Text":"Inside cells, they are found in specific organelles such as the Golgi complexes,"},{"Start":"06:38.390 ","End":"06:41.405","Text":"secretory granules, and lysosomes."},{"Start":"06:41.405 ","End":"06:45.680","Text":"The oligosaccharide portions of glycoproteins are less"},{"Start":"06:45.680 ","End":"06:50.060","Text":"repetitive than the GAG chains of proteoglycans and they are"},{"Start":"06:50.060 ","End":"06:52.895","Text":"rich in information forming"},{"Start":"06:52.895 ","End":"06:59.195","Text":"highly specific sites for recognition and high-affinity binding by other proteins."},{"Start":"06:59.195 ","End":"07:02.490","Text":"We\u0027ve talked about proteoglycans,"},{"Start":"07:02.490 ","End":"07:07.640","Text":"glycoproteins, and now we are going to talk about glycolipids."},{"Start":"07:07.640 ","End":"07:13.040","Text":"Glycolipids are membrane lipids in which the hydrophilic head,"},{"Start":"07:13.040 ","End":"07:16.790","Text":"remember hydro, water, philic, love,"},{"Start":"07:16.790 ","End":"07:18.549","Text":"the hydrophilic head groups are oligosaccharides,"},{"Start":"07:18.549 ","End":"07:21.370","Text":"they can interact with water."},{"Start":"07:21.370 ","End":"07:26.645","Text":"These are membrane lipids in which the hydrophilic head groups are oligosaccharides,"},{"Start":"07:26.645 ","End":"07:29.525","Text":"which as in glycoproteins,"},{"Start":"07:29.525 ","End":"07:35.885","Text":"act as specific sites for recognition by carbohydrate-binding proteins."},{"Start":"07:35.885 ","End":"07:40.300","Text":"Drawing the parallel between glycolipids and glycoproteins,"},{"Start":"07:40.300 ","End":"07:44.030","Text":"they have this ability to act as"},{"Start":"07:44.030 ","End":"07:49.838","Text":"specific sites of recognition for carbohydrate-binding proteins,"},{"Start":"07:49.838 ","End":"07:52.130","Text":"they\u0027re bound to these lipids."},{"Start":"07:52.130 ","End":"07:55.120","Text":"If we look here at glycolipid,"},{"Start":"07:55.120 ","End":"08:01.775","Text":"you have the lipids of the membrane and then you have the GAG,"},{"Start":"08:01.775 ","End":"08:04.500","Text":"the sugar part bound to that,"},{"Start":"08:04.500 ","End":"08:07.580","Text":"and then you will have carbohydrate-binding proteins,"},{"Start":"08:07.580 ","End":"08:09.980","Text":"proteins that bind this part,"},{"Start":"08:09.980 ","End":"08:12.650","Text":"the carbohydrate part of the glycolipid,"},{"Start":"08:12.650 ","End":"08:17.900","Text":"and it is specific and allows this specific recognition."},{"Start":"08:17.900 ","End":"08:22.514","Text":"The study of glycoproteins in recent years has grown and"},{"Start":"08:22.514 ","End":"08:29.749","Text":"the term glycobiology has now become a more familiar term and it means biology,"},{"Start":"08:29.749 ","End":"08:32.550","Text":"the study and glyco-sugar,"},{"Start":"08:32.550 ","End":"08:35.420","Text":"it\u0027s the study of the structure and function of"},{"Start":"08:35.420 ","End":"08:39.965","Text":"glycoconjugates, glycoproteins, glycolipids."},{"Start":"08:39.965 ","End":"08:44.420","Text":"This is 1 of the most active and exciting areas of biochemistry and cell biology,"},{"Start":"08:44.420 ","End":"08:46.610","Text":"as is becoming increasingly clear,"},{"Start":"08:46.610 ","End":"08:49.430","Text":"cells use specifically oligosaccharides to encode"},{"Start":"08:49.430 ","End":"08:53.570","Text":"important information about intracellular targeting of proteins."},{"Start":"08:53.570 ","End":"08:58.160","Text":"If there is this specific sequence that can be recognized by"},{"Start":"08:58.160 ","End":"09:02.960","Text":"a specific protein or other molecule and you have"},{"Start":"09:02.960 ","End":"09:08.210","Text":"these similar things inside the cell as well it basically"},{"Start":"09:08.210 ","End":"09:13.715","Text":"encodes important information about the intracellular targeting of proteins,"},{"Start":"09:13.715 ","End":"09:16.955","Text":"about cell-cell interaction because these can interact with"},{"Start":"09:16.955 ","End":"09:21.234","Text":"other things about tissue development and extracellular signals,"},{"Start":"09:21.234 ","End":"09:26.915","Text":"glycobiology is actually a field that is growing and gaining interest."},{"Start":"09:26.915 ","End":"09:31.550","Text":"With this, we completed the introduction to glycoconjugates and we learned about"},{"Start":"09:31.550 ","End":"09:36.860","Text":"the definition of glycoconjugates and the different types of glycoconjugates."},{"Start":"09:36.860 ","End":"09:38.285","Text":"In the next section,"},{"Start":"09:38.285 ","End":"09:40.760","Text":"we will talk about specific glycoconjugates,"},{"Start":"09:40.760 ","End":"09:45.480","Text":"but first, how about we do some exercises?"}],"ID":30530},{"Watched":false,"Name":"Exercise 1","Duration":"1m 10s","ChapterTopicVideoID":28981,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.355","Text":"We have an exercise covering the lesson in which we introduced glycoconjugates."},{"Start":"00:05.355 ","End":"00:07.395","Text":"Let\u0027s start with something straightforward."},{"Start":"00:07.395 ","End":"00:08.760","Text":"What are glycoconjugates,"},{"Start":"00:08.760 ","End":"00:11.745","Text":"and what are the 3 main types mentioned?"},{"Start":"00:11.745 ","End":"00:14.190","Text":"Glycoconjugates are molecules composed of"},{"Start":"00:14.190 ","End":"00:18.715","Text":"carbohydrates covalently joined to another type of molecule,"},{"Start":"00:18.715 ","End":"00:21.390","Text":"a protein or a lipid, for example."},{"Start":"00:21.390 ","End":"00:28.395","Text":"There are proteoglycans, glycoproteins, and glycolipids."},{"Start":"00:28.395 ","End":"00:34.230","Text":"The first 2 glycoconjugates are made of proteins bound to carbohydrates,"},{"Start":"00:34.230 ","End":"00:39.780","Text":"while glycolipids are glycoconjugates of carbohydrates and lipids."},{"Start":"00:39.780 ","End":"00:44.595","Text":"So with that, we define glycoconjugates: conjugate,"},{"Start":"00:44.595 ","End":"00:48.192","Text":"combined, bound; glyco, sugar."},{"Start":"00:48.192 ","End":"00:50.903","Text":"It\u0027s sugar that is bound to either a protein,"},{"Start":"00:50.903 ","End":"00:54.080","Text":"as in the case of proteoglycans,"},{"Start":"00:54.080 ","End":"00:58.630","Text":"proteo and glycans, or glycoproteins."},{"Start":"00:58.630 ","End":"01:06.905","Text":"2 types of glycoconjugates are of sugar and a protein or with a lipid, glycolipids."},{"Start":"01:06.905 ","End":"01:10.740","Text":"Those are our 3 types. Let\u0027s move on."}],"ID":30531},{"Watched":false,"Name":"Exercise 2","Duration":"1m 2s","ChapterTopicVideoID":28982,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:01.830","Text":"Hopefully, you\u0027re ready for another exercise,"},{"Start":"00:01.830 ","End":"00:04.620","Text":"testing the knowledge on intro to glycoconjugates."},{"Start":"00:04.620 ","End":"00:08.025","Text":"What roles do glycoconjugates play in organisms?"},{"Start":"00:08.025 ","End":"00:12.975","Text":"Glycoconjugates play important roles as stored fuels,"},{"Start":"00:12.975 ","End":"00:16.320","Text":"such as starch, glycogen, and dextran."},{"Start":"00:16.320 ","End":"00:21.430","Text":"They also serve as structural materials,"},{"Start":"00:22.250 ","End":"00:25.320","Text":"and these are cellulose,"},{"Start":"00:25.320 ","End":"00:28.050","Text":"chitin, and peptidoglycans."},{"Start":"00:28.050 ","End":"00:30.635","Text":"Polysaccharides and oligosaccharides,"},{"Start":"00:30.635 ","End":"00:37.130","Text":"are also and can play roles as information carriers."},{"Start":"00:37.130 ","End":"00:42.200","Text":"They serve as destination labels for some proteins and as mediators of"},{"Start":"00:42.200 ","End":"00:44.930","Text":"specific cell-cell interactions and interactions"},{"Start":"00:44.930 ","End":"00:48.680","Text":"between cells and the extracellular matrix."},{"Start":"00:48.680 ","End":"00:54.455","Text":"We have glycoconjugates that play roles in stored fuels,"},{"Start":"00:54.455 ","End":"00:59.570","Text":"structural materials, and as information carriers."},{"Start":"00:59.570 ","End":"01:02.460","Text":"We convene in another exercise."}],"ID":30532},{"Watched":false,"Name":"Exercise 3","Duration":"4m 5s","ChapterTopicVideoID":28983,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:01.965","Text":"Let\u0027s do another exercise."},{"Start":"00:01.965 ","End":"00:06.180","Text":"Testing our knowledge on the intro to glycoconjugates."},{"Start":"00:06.180 ","End":"00:09.405","Text":"Fill in the blank with a correct glycoconjugate."},{"Start":"00:09.405 ","End":"00:14.295","Text":"1, blank, are major components of connective tissues such as cartilage,"},{"Start":"00:14.295 ","End":"00:16.680","Text":"in which there are many non-covalent interactions,"},{"Start":"00:16.680 ","End":"00:19.440","Text":"provides strength and flexibility."},{"Start":"00:19.440 ","End":"00:21.960","Text":"2, blank,"},{"Start":"00:21.960 ","End":"00:25.110","Text":"have one or several oligosaccharides of"},{"Start":"00:25.110 ","End":"00:28.980","Text":"varying complexity joined covalently to a protein."},{"Start":"00:28.980 ","End":"00:34.620","Text":"The oligosaccharide portion of these are not very repetitive and are rich in information"},{"Start":"00:34.620 ","End":"00:36.740","Text":"forming highly specific sites for"},{"Start":"00:36.740 ","End":"00:41.250","Text":"recognition and high affinity binding by other proteins."},{"Start":"00:41.250 ","End":"00:48.755","Text":"3, the glycoconjugate of a specific type are membrane lipids in which"},{"Start":"00:48.755 ","End":"00:52.970","Text":"the hydrophilic head groups are oligosaccharides which act as"},{"Start":"00:52.970 ","End":"00:57.845","Text":"specific sites for recognition by carbohydrate binding proteins."},{"Start":"00:57.845 ","End":"01:03.920","Text":"Let\u0027s think what were the 3 types of glycoconjugates we learned about."},{"Start":"01:03.920 ","End":"01:07.520","Text":"They will be either conjugated to protein or lipid,"},{"Start":"01:07.520 ","End":"01:11.300","Text":"and there are 2 types of glycoconjugates with proteins."},{"Start":"01:11.300 ","End":"01:20.910","Text":"1, starts with the term protein and is called the proteoglycan."},{"Start":"01:20.910 ","End":"01:29.215","Text":"2, is another one that is a glycoconjugate with protein and ends with the term protein."},{"Start":"01:29.215 ","End":"01:33.250","Text":"This one is flip the sugar first and the protein next,"},{"Start":"01:33.250 ","End":"01:38.389","Text":"so glycoprotein,"},{"Start":"01:38.389 ","End":"01:43.690","Text":"and the third is similarly named as in the glycoprotein,"},{"Start":"01:43.690 ","End":"01:48.670","Text":"but is bound to a lipid and is a glycolipid."},{"Start":"01:48.860 ","End":"01:59.530","Text":"Now we want to associate to these with these sentences right here."},{"Start":"02:00.020 ","End":"02:04.210","Text":"We have a hint that this one is lipid."},{"Start":"02:04.210 ","End":"02:06.895","Text":"Most likely we can say,"},{"Start":"02:06.895 ","End":"02:13.890","Text":"okay, 3 goes to 3, so glycolipid."},{"Start":"02:13.890 ","End":"02:18.990","Text":"Let\u0027s try to see here it mentions that it\u0027s covalently linked to a protein,"},{"Start":"02:18.990 ","End":"02:21.520","Text":"so yes, it will be one of these."},{"Start":"02:21.530 ","End":"02:24.150","Text":"Let\u0027s step back to 1,"},{"Start":"02:24.150 ","End":"02:27.955","Text":"are major components of connective tissues such as cartilage,"},{"Start":"02:27.955 ","End":"02:29.920","Text":"in which there are many non-covalent interactions,"},{"Start":"02:29.920 ","End":"02:32.980","Text":"and provides strength and flexibility."},{"Start":"02:32.980 ","End":"02:40.465","Text":"This one focuses on the ability of the flexibility that the proteins give."},{"Start":"02:40.465 ","End":"02:44.930","Text":"They have this complex structure that allows this flexibility with a proteoglycan,"},{"Start":"02:44.930 ","End":"02:50.200","Text":"so this sounds like the proteoglycan."},{"Start":"02:50.200 ","End":"02:56.090","Text":"Proteoglycans are major components of connective tissue such as cartilage,"},{"Start":"02:56.090 ","End":"02:58.190","Text":"in which there are many non-covalent interactions,"},{"Start":"02:58.190 ","End":"03:00.005","Text":"provide strength and flexibility."},{"Start":"03:00.005 ","End":"03:04.820","Text":"That leaves us with the other type of glycoconjugate with protein,"},{"Start":"03:04.820 ","End":"03:08.465","Text":"which is the glycoprotein."},{"Start":"03:08.465 ","End":"03:12.365","Text":"Glycoproteins have one or several oligosaccharides"},{"Start":"03:12.365 ","End":"03:16.450","Text":"of varying complexity joined covalently to a protein."},{"Start":"03:16.450 ","End":"03:21.770","Text":"The oligosaccharide portions of these are not very repetitive,"},{"Start":"03:21.770 ","End":"03:25.520","Text":"less than the glycosaminoglycan chains of proteoglycans,"},{"Start":"03:25.520 ","End":"03:27.200","Text":"so less repetitive than here,"},{"Start":"03:27.200 ","End":"03:30.470","Text":"the GAGs and the proteoglycans."},{"Start":"03:30.470 ","End":"03:33.650","Text":"They are rich in information,"},{"Start":"03:33.650 ","End":"03:36.815","Text":"forming highly specific sites for"},{"Start":"03:36.815 ","End":"03:41.030","Text":"recognition and high affinity binding by other proteins."},{"Start":"03:41.030 ","End":"03:44.780","Text":"This leaves us with the glycolipids that"},{"Start":"03:44.780 ","End":"03:48.305","Text":"are membrane lipids in which the hydrophilic head groups are"},{"Start":"03:48.305 ","End":"03:52.880","Text":"oligosaccharides which act as specific sites for"},{"Start":"03:52.880 ","End":"03:58.515","Text":"recognition by carbohydrate binding proteins."},{"Start":"03:58.515 ","End":"04:05.550","Text":"With that, we completed this exercise covering the introduction to glycoconjugates"}],"ID":30533},{"Watched":false,"Name":"Proteoglycans Part 1","Duration":"10m 27s","ChapterTopicVideoID":28984,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.650","Text":"Welcome to a lesson on proteoglycans within the chapter on glycoconjugates."},{"Start":"00:04.650 ","End":"00:08.670","Text":"In this section, we will learn about proteoglycans and their significance,"},{"Start":"00:08.670 ","End":"00:12.885","Text":"and this is mostly within the plasma membrane and extracellular matrix."},{"Start":"00:12.885 ","End":"00:17.580","Text":"We\u0027re going to split this lesson into 3 parts and we will"},{"Start":"00:17.580 ","End":"00:23.010","Text":"start with Part 1 of proteoglycans where we will talk about proteoglycan structure,"},{"Start":"00:23.010 ","End":"00:28.770","Text":"proteoglycan significance, and role and heparin sulfate in proteoglycans."},{"Start":"00:28.770 ","End":"00:34.095","Text":"Proteoglycans are glycosaminoglycan-containing macromolecules"},{"Start":"00:34.095 ","End":"00:37.200","Text":"of the cell surface and extracellular matrix."},{"Start":"00:37.200 ","End":"00:40.935","Text":"Proteoglycans are proteins that are heavily glycosylated,"},{"Start":"00:40.935 ","End":"00:43.385","Text":"meaning have sugars attached to them."},{"Start":"00:43.385 ","End":"00:47.390","Text":"The basic proteoglycan unit consists of a core protein with"},{"Start":"00:47.390 ","End":"00:51.335","Text":"1 or more covalently attached glycosaminoglycans,"},{"Start":"00:51.335 ","End":"00:52.760","Text":"GAG for short,"},{"Start":"00:52.760 ","End":"00:58.635","Text":"so covalently attached GAG chain or chains."},{"Start":"00:58.635 ","End":"01:01.610","Text":"Matrix mammalian cells can produce at least 30 types of"},{"Start":"01:01.610 ","End":"01:05.405","Text":"molecules that are members of the proteoglycans superfamily."},{"Start":"01:05.405 ","End":"01:08.074","Text":"These molecules act as tissue organizers,"},{"Start":"01:08.074 ","End":"01:10.685","Text":"influence the development of specialized tissues,"},{"Start":"01:10.685 ","End":"01:14.030","Text":"mediate the activities of various growth factors,"},{"Start":"01:14.030 ","End":"01:18.680","Text":"and regulate the extracellular assembly of collagen fibrils,"},{"Start":"01:18.680 ","End":"01:19.970","Text":"collagen we had introduced,"},{"Start":"01:19.970 ","End":"01:23.255","Text":"and fibrils in previous lessons."},{"Start":"01:23.255 ","End":"01:26.185","Text":"The basic proteoglycan unit consists of"},{"Start":"01:26.185 ","End":"01:31.595","Text":"a core protein with covalently attached glycosaminoglycans,"},{"Start":"01:31.595 ","End":"01:34.120","Text":"again, GAG for short."},{"Start":"01:34.120 ","End":"01:39.430","Text":"For example, the sheet-like extracellular matrix,"},{"Start":"01:39.430 ","End":"01:42.130","Text":"which is also known as the basal lamina,"},{"Start":"01:42.130 ","End":"01:45.925","Text":"that separates organized groups of cells,"},{"Start":"01:45.925 ","End":"01:52.655","Text":"contains a family of core proteins with the molecular weight of about 20,000-40,000,"},{"Start":"01:52.655 ","End":"01:58.134","Text":"each with several covalently attached heparan sulfate chains."},{"Start":"01:58.134 ","End":"02:00.985","Text":"Reminder of something we went over in a previous lesson,"},{"Start":"02:00.985 ","End":"02:05.955","Text":"heparin sulfate is structurally similar to heparin,"},{"Start":"02:05.955 ","End":"02:11.390","Text":"but has a lower density of sulfite esters."},{"Start":"02:11.390 ","End":"02:14.030","Text":"If we compare heparin to heparan,"},{"Start":"02:14.030 ","End":"02:18.095","Text":"heparan is similar to heparin, structurally,"},{"Start":"02:18.095 ","End":"02:22.940","Text":"similar structure, yet lower"},{"Start":"02:22.940 ","End":"02:28.835","Text":"density of sulfate esters."},{"Start":"02:28.835 ","End":"02:34.040","Text":"Sulfate esters are the type of bond."},{"Start":"02:34.040 ","End":"02:41.270","Text":"Now the point of attachment is commonly a serine residue to which the gag,"},{"Start":"02:41.270 ","End":"02:45.935","Text":"the glycosaminoglycan is joined through a try saccharide bridge,"},{"Start":"02:45.935 ","End":"02:50.920","Text":"meaning a bridge made of 3 sugar molecules, 3 saccharides."},{"Start":"02:50.920 ","End":"02:52.430","Text":"If we look here at this figure,"},{"Start":"02:52.430 ","End":"02:54.950","Text":"we have the proteoglycan structure showing"},{"Start":"02:54.950 ","End":"03:00.095","Text":"the trace saccharide bridge with a typical trisaccharide linker in blue,"},{"Start":"03:00.095 ","End":"03:02.270","Text":"which connects a glycosaminoglycan."},{"Start":"03:02.270 ","End":"03:10.895","Text":"In this case, there\u0027s chondroitin sulfate in this pink to a serine residue,"},{"Start":"03:10.895 ","End":"03:12.800","Text":"which is in lighter pink,"},{"Start":"03:12.800 ","End":"03:14.915","Text":"maybe this is few so I don\u0027t know,"},{"Start":"03:14.915 ","End":"03:16.670","Text":"in the core protein."},{"Start":"03:16.670 ","End":"03:18.080","Text":"So this is our core protein,"},{"Start":"03:18.080 ","End":"03:21.200","Text":"and then you have the amino terminus and the carboxyl terminus."},{"Start":"03:21.200 ","End":"03:23.165","Text":"This would have the C here."},{"Start":"03:23.165 ","End":"03:24.994","Text":"This would have the NH,"},{"Start":"03:24.994 ","End":"03:26.390","Text":"that\u0027s the amino terminus,"},{"Start":"03:26.390 ","End":"03:30.275","Text":"and this thing is the core protein right here."},{"Start":"03:30.275 ","End":"03:34.525","Text":"You have this chondroitin sulfate attached by this try saccharide bridge,"},{"Start":"03:34.525 ","End":"03:36.800","Text":"this tries saccharide linker in this baby blue."},{"Start":"03:36.800 ","End":"03:38.570","Text":"Then you have the baby pink."},{"Start":"03:38.570 ","End":"03:43.385","Text":"It is attached to the serine residue on the core protein."},{"Start":"03:43.385 ","End":"03:47.675","Text":"Now the xylose residue at the reducing end of the linker,"},{"Start":"03:47.675 ","End":"03:49.595","Text":"which is right here,"},{"Start":"03:49.595 ","End":"03:56.240","Text":"is joined by its anomeric carbon to the hydroxyl of the Ser residue."},{"Start":"03:56.240 ","End":"03:59.465","Text":"Now, you see here the different types of bonds,"},{"Start":"03:59.465 ","End":"04:02.233","Text":"and these can be written as Beta 1,"},{"Start":"04:02.233 ","End":"04:03.920","Text":"4 in this fashion as well."},{"Start":"04:03.920 ","End":"04:07.220","Text":"This would be Beta 1, 4 or if you write 3 for 3."},{"Start":"04:07.220 ","End":"04:14.059","Text":"It\u0027s showing the bonds between the molecules within the chondroitin sulfate."},{"Start":"04:14.059 ","End":"04:17.935","Text":"Here this bond is a Beta 1, 3 bond between."},{"Start":"04:17.935 ","End":"04:19.860","Text":"Here you have the Beta 1,"},{"Start":"04:19.860 ","End":"04:22.260","Text":"4 between here you have Beta 1,"},{"Start":"04:22.260 ","End":"04:24.875","Text":"3 and between the galactose and silos,"},{"Start":"04:24.875 ","End":"04:26.240","Text":"you have Beta 1, 4."},{"Start":"04:26.240 ","End":"04:29.460","Text":"The covalently attached glycosaminoglycans,"},{"Start":"04:29.460 ","End":"04:31.835","Text":"GAGs are highly negatively charged"},{"Start":"04:31.835 ","End":"04:37.445","Text":"because of sulfate or carboxyl groups on most of their sugars."},{"Start":"04:37.445 ","End":"04:42.140","Text":"Because of sulfate or carboxyl groups on most of their sugars."},{"Start":"04:42.140 ","End":"04:44.135","Text":"They\u0027re highly negative charge,"},{"Start":"04:44.135 ","End":"04:47.015","Text":"which attracts us mitotically active cat ions,"},{"Start":"04:47.015 ","End":"04:55.860","Text":"like sodium ions, which causes large amounts of water to be incorporated into the matrix."},{"Start":"04:56.860 ","End":"05:03.725","Text":"This negative charge of the GAGs that is due to these groups"},{"Start":"05:03.725 ","End":"05:11.275","Text":"result in water being pulled in and incorporated into the matrix."},{"Start":"05:11.275 ","End":"05:15.230","Text":"This results in porous hydrated gels,"},{"Start":"05:15.230 ","End":"05:18.560","Text":"which are responsible for the turgor and"},{"Start":"05:18.560 ","End":"05:22.985","Text":"enables the matrix to withstand compressive force,"},{"Start":"05:22.985 ","End":"05:26.450","Text":"meaning that even when there\u0027s force on it,"},{"Start":"05:26.450 ","End":"05:31.670","Text":"it actually has the ability to withstand and maintain its structure."},{"Start":"05:31.670 ","End":"05:34.220","Text":"As we mentioned, the extracellular matrix,"},{"Start":"05:34.220 ","End":"05:40.295","Text":"we can also say that many proteoglycans are secreted into the extracellular matrix,"},{"Start":"05:40.295 ","End":"05:44.025","Text":"but some are integral membrane proteins."},{"Start":"05:44.025 ","End":"05:48.350","Text":"We see here the plasma membrane and we see"},{"Start":"05:48.350 ","End":"05:53.590","Text":"the proteoglycans are these like chimney sweeps, these little brushes."},{"Start":"05:53.590 ","End":"05:57.890","Text":"These are within the extracellular matrix because this is"},{"Start":"05:57.890 ","End":"06:02.540","Text":"the plasma membrane with actin filaments to the membrane is within here."},{"Start":"06:02.540 ","End":"06:07.025","Text":"This right here is the extracellular matrix and we have a proteoglycan here."},{"Start":"06:07.025 ","End":"06:12.470","Text":"As for an example of 1 that is integral as a membrane protein,"},{"Start":"06:12.470 ","End":"06:14.825","Text":"we will mention Cindy can,"},{"Start":"06:14.825 ","End":"06:18.035","Text":"which is a core protein of the molecular weight of about"},{"Start":"06:18.035 ","End":"06:22.250","Text":"56,000 and has a single transmembrane domain."},{"Start":"06:22.250 ","End":"06:24.950","Text":"It goes through the membrane and"},{"Start":"06:24.950 ","End":"06:34.250","Text":"an extracellular domain bearing 3 chains of heparin sulfate and 2 of chondroitin sulfate,"},{"Start":"06:34.250 ","End":"06:38.545","Text":"each attached to a serine residue."},{"Start":"06:38.545 ","End":"06:45.530","Text":"We see here the example of this core protein that has a single transmembrane domain."},{"Start":"06:45.530 ","End":"06:48.470","Text":"This is the transmembrane domain right here."},{"Start":"06:48.470 ","End":"06:51.260","Text":"It\u0027s going through the plasma membrane."},{"Start":"06:51.260 ","End":"06:55.400","Text":"It has an extracellular domain bearing 3 chains of heparin sulfate,"},{"Start":"06:55.400 ","End":"07:01.665","Text":"as you see here and here, and here."},{"Start":"07:01.665 ","End":"07:07.620","Text":"2, chondroitin sulfate as you see here 1,"},{"Start":"07:07.620 ","End":"07:15.075","Text":"and here 2 each attached to the serine residue."},{"Start":"07:15.075 ","End":"07:19.100","Text":"Basically what we see in this figure"},{"Start":"07:19.100 ","End":"07:22.820","Text":"is a proteoglycan structure of an integral membrane protein."},{"Start":"07:22.820 ","End":"07:26.735","Text":"This is the schematic diagram of syndecan or syndecan,"},{"Start":"07:26.735 ","End":"07:28.790","Text":"a core protein of the plasma membrane."},{"Start":"07:28.790 ","End":"07:31.160","Text":"The amino terminal domain,"},{"Start":"07:31.160 ","End":"07:36.230","Text":"which is right here on the extracellular surface of the membrane,"},{"Start":"07:36.230 ","End":"07:40.670","Text":"is covalently attached by trisaccharide linkers,"},{"Start":"07:40.670 ","End":"07:44.960","Text":"such as seen in the previous figure, which was right here."},{"Start":"07:44.960 ","End":"07:47.045","Text":"This trisaccharides linker."},{"Start":"07:47.045 ","End":"07:51.109","Text":"That\u0027s how this is covalently attached."},{"Start":"07:51.109 ","End":"07:53.570","Text":"Now, this amino-terminal domain on"},{"Start":"07:53.570 ","End":"07:56.660","Text":"the extracellular surface of the membrane that\u0027s covalently attached by"},{"Start":"07:56.660 ","End":"08:05.110","Text":"these trisaccharides linkers to 3 heparin sulfate chains and the 2 chondroitin."},{"Start":"08:05.110 ","End":"08:07.055","Text":"Let\u0027s repeat that to drill it in."},{"Start":"08:07.055 ","End":"08:09.050","Text":"The amino terminal domain on"},{"Start":"08:09.050 ","End":"08:11.885","Text":"the extracellular surface of the membrane is covalently attached"},{"Start":"08:11.885 ","End":"08:13.340","Text":"by these trisaccharides linkers to"},{"Start":"08:13.340 ","End":"08:17.105","Text":"3 heparin sulfate chains and 2 chondroitin sulfate chains."},{"Start":"08:17.105 ","End":"08:20.120","Text":"Some core proteins syndecan is here and"},{"Start":"08:20.120 ","End":"08:23.280","Text":"others are anchored by a single transmembrane helix,"},{"Start":"08:23.280 ","End":"08:24.350","Text":"and that\u0027s what we see here."},{"Start":"08:24.350 ","End":"08:29.750","Text":"You have the transmembrane domain and it\u0027s a helix, a spiral."},{"Start":"08:29.750 ","End":"08:38.745","Text":"Others, for example, glycans are anchored by a covalently attached membrane glycolipid."},{"Start":"08:38.745 ","End":"08:40.400","Text":"A third class of core proteins."},{"Start":"08:40.400 ","End":"08:41.810","Text":"The protein is released into"},{"Start":"08:41.810 ","End":"08:45.815","Text":"the extracellular space where it forms part of the basement membrane."},{"Start":"08:45.815 ","End":"08:49.820","Text":"Now if we look down here b of the figure is showing us"},{"Start":"08:49.820 ","End":"08:54.440","Text":"the structure of the heparin sulfate and I\u0027ll explain that in more detail in a minute."},{"Start":"08:54.440 ","End":"08:58.665","Text":"But I want to mention about syndecan"},{"Start":"08:58.665 ","End":"09:04.850","Text":"that there are at least 4 members of the syndecan family in mammals."},{"Start":"09:04.850 ","End":"09:08.420","Text":"Now, another family of proteins is the glycocalyx,"},{"Start":"09:08.420 ","End":"09:14.225","Text":"which I mentioned when I described this figure right here with 6 members."},{"Start":"09:14.225 ","End":"09:20.495","Text":"These proteins that are attached to the membrane by a lipid anchor,"},{"Start":"09:20.495 ","End":"09:23.960","Text":"a derivative of the membrane lipid are there for"},{"Start":"09:23.960 ","End":"09:28.280","Text":"different from the type which are the syndecan,"},{"Start":"09:28.280 ","End":"09:31.520","Text":"the family of these membrane proteins."},{"Start":"09:31.520 ","End":"09:37.383","Text":"Again, I mentioned in this figure how these are different and"},{"Start":"09:37.383 ","End":"09:43.310","Text":"it\u0027s basically when you have a covalently attached membrane glycolipid."},{"Start":"09:43.310 ","End":"09:46.460","Text":"As I explained when I went over the figure,"},{"Start":"09:46.460 ","End":"09:51.155","Text":"the glycans are attached to the membrane by"},{"Start":"09:51.155 ","End":"09:57.140","Text":"a glycolipid versus the transmembrane helix that is seen in this figure,"},{"Start":"09:57.140 ","End":"10:02.150","Text":"the heparin sulfate moieties in proteoglycans bind a variety of"},{"Start":"10:02.150 ","End":"10:06.845","Text":"extracellular ligands and thereby modulate"},{"Start":"10:06.845 ","End":"10:12.355","Text":"the ligand\u0027s interaction with specific receptors of the cell surface."},{"Start":"10:12.355 ","End":"10:17.630","Text":"With this, we completed Part 1 of proteoglycans and we covered proteoglycan structure,"},{"Start":"10:17.630 ","End":"10:21.785","Text":"proteoglycan insignificance and role and heparan sulfate in proteoglycans."},{"Start":"10:21.785 ","End":"10:27.240","Text":"Keep this in mind because we\u0027re going to use this information to build on in Part 2."}],"ID":30534},{"Watched":false,"Name":"Proteoglycans Part 2","Duration":"12m 41s","ChapterTopicVideoID":28985,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:06.270","Text":"Welcome to Part 2 of proteoglycans within the chapter of glycoconjugates."},{"Start":"00:06.270 ","End":"00:08.340","Text":"In this section, we will learn about"},{"Start":"00:08.340 ","End":"00:11.730","Text":"the glycan moiety of proteoglycans, the sugar moiety,"},{"Start":"00:11.730 ","End":"00:14.940","Text":"and heparan sulfate\u0027s role specifically how it"},{"Start":"00:14.940 ","End":"00:19.185","Text":"contributes within the context of proteoglycans."},{"Start":"00:19.185 ","End":"00:23.955","Text":"Detailed examination of the glycan moiety of proteoglycans"},{"Start":"00:23.955 ","End":"00:29.415","Text":"has revealed a sequence heterogeneity that is not random, hetero different."},{"Start":"00:29.415 ","End":"00:34.755","Text":"Therefore, it means that it\u0027s a sequence with different components, different monomers."},{"Start":"00:34.755 ","End":"00:39.460","Text":"Some domains typically 3-8 disaccharide units long"},{"Start":"00:39.460 ","End":"00:44.975","Text":"differ from neighboring domains and sequence and inability to bind to specific proteins."},{"Start":"00:44.975 ","End":"00:46.865","Text":"Heparan sulfate, for example,"},{"Start":"00:46.865 ","End":"00:50.570","Text":"is initially synthesized as a long polymer of"},{"Start":"00:50.570 ","End":"00:55.160","Text":"about 50-200 disaccharide units and glucuronic acid."},{"Start":"00:55.160 ","End":"00:59.340","Text":"Remember glucuronic acid is GlcA."},{"Start":"00:59.340 ","End":"01:05.470","Text":"Going back, heparan sulfate initially is synthesized as a long polymer of"},{"Start":"01:05.470 ","End":"01:07.486","Text":"50-200 disaccharide units of"},{"Start":"01:07.486 ","End":"01:11.945","Text":"alternating N-acetylglucosamine and glucuronic acid residues."},{"Start":"01:11.945 ","End":"01:15.125","Text":"That is basically what we see here."},{"Start":"01:15.125 ","End":"01:18.290","Text":"This simple chain is acted on by a series of enzymes that"},{"Start":"01:18.290 ","End":"01:22.030","Text":"introduce alterations in specific regions,"},{"Start":"01:22.030 ","End":"01:26.375","Text":"first creating clusters of N-sulfated glucosamine residues."},{"Start":"01:26.375 ","End":"01:31.730","Text":"These clusters then attract enzymes that carry out further modifications."},{"Start":"01:31.730 ","End":"01:36.167","Text":"The result is a polymer in which highly sulfated domains, S domains."},{"Start":"01:36.167 ","End":"01:40.490","Text":"What we see here in green are the S domains,"},{"Start":"01:40.490 ","End":"01:47.180","Text":"alternate with domains having unmodified residues and acetylated or NA domains,"},{"Start":"01:47.180 ","End":"01:49.880","Text":"which is what you see here in gray."},{"Start":"01:49.880 ","End":"01:55.130","Text":"Now the exact pattern of sulfation in the S domain differs in different proteoglycans,"},{"Start":"01:55.130 ","End":"01:59.150","Text":"at least 32 different disaccharide units are possible."},{"Start":"01:59.150 ","End":"02:03.080","Text":"Let\u0027s look at this figure again and explain what we\u0027re"},{"Start":"02:03.080 ","End":"02:07.130","Text":"seeing and the characteristics of the heparan sulfate which we saw."},{"Start":"02:07.130 ","End":"02:10.197","Text":"There are 3 of them in syndecan for example."},{"Start":"02:10.197 ","End":"02:13.465","Text":"Along a heparan sulfate chain,"},{"Start":"02:13.465 ","End":"02:16.434","Text":"regions rich in sulfated sugars,"},{"Start":"02:16.434 ","End":"02:20.790","Text":"so you see the S here or O-sulfate."},{"Start":"02:20.790 ","End":"02:24.800","Text":"These little red dots are the sulfated sugars, the S domains,"},{"Start":"02:24.800 ","End":"02:28.715","Text":"green here alternate with regions with"},{"Start":"02:28.715 ","End":"02:36.755","Text":"chiefly unmodified residues of N-acetylglucosamine and glucuronic acid."},{"Start":"02:36.755 ","End":"02:39.230","Text":"What we see here."},{"Start":"02:39.230 ","End":"02:45.935","Text":"You have these alternated regions of N-acetylglucosamine and glucuronic acid,"},{"Start":"02:45.935 ","End":"02:48.080","Text":"red and purple, red and purple."},{"Start":"02:48.080 ","End":"02:52.190","Text":"These regions rich in sulfated sugars,"},{"Start":"02:52.190 ","End":"02:59.630","Text":"the S-domain alternate with regions with chiefly unmodified residues of GlcNAc and GlcA,"},{"Start":"02:59.630 ","End":"03:03.340","Text":"the NA domains, they alternate."},{"Start":"03:03.340 ","End":"03:06.440","Text":"So one of the S domains is shown in more detail,"},{"Start":"03:06.440 ","End":"03:13.395","Text":"so expanding here on right the S domain is what we see here."},{"Start":"03:13.395 ","End":"03:18.500","Text":"This is the S domain and you see that it has the different sulfates."},{"Start":"03:18.500 ","End":"03:21.590","Text":"Now, this is revealing a high density of modified residues."},{"Start":"03:21.590 ","End":"03:23.210","Text":"You have glucuronic acid,"},{"Start":"03:23.210 ","End":"03:29.630","Text":"GlcA in purple with a sulfate ester at C6"},{"Start":"03:29.630 ","End":"03:36.590","Text":"and then you have the IdoA with a sulfate ester at C2."},{"Start":"03:36.590 ","End":"03:41.248","Text":"When you see it\u0027s coming down in this direction,"},{"Start":"03:41.248 ","End":"03:47.655","Text":"this is at C2 carbon 2,"},{"Start":"03:47.655 ","End":"03:50.501","Text":"because we have, this is 1 carbon,"},{"Start":"03:50.501 ","End":"03:52.950","Text":"this is where 2 is."},{"Start":"03:52.950 ","End":"03:54.525","Text":"This is where 3 is,"},{"Start":"03:54.525 ","End":"03:56.070","Text":"4, 5, 6."},{"Start":"03:56.070 ","End":"04:01.510","Text":"The 1 that is pointing up is at C6,"},{"Start":"04:01.510 ","End":"04:05.525","Text":"carbon 6, the molecule of the cyclic structure."},{"Start":"04:05.525 ","End":"04:11.195","Text":"Now the exact pattern of sulfation in the S domain differs among proteoglycans."},{"Start":"04:11.195 ","End":"04:18.665","Text":"As mentioned there can be 32 different disaccharide units as possibilities."},{"Start":"04:18.665 ","End":"04:23.150","Text":"As mentioned, the same core protein can display different heparan sulfate structures."},{"Start":"04:23.150 ","End":"04:25.130","Text":"These can be a little different in the structure"},{"Start":"04:25.130 ","End":"04:27.290","Text":"when synthesized in different cell types."},{"Start":"04:27.290 ","End":"04:28.835","Text":"Let\u0027s expand on that."},{"Start":"04:28.835 ","End":"04:30.770","Text":"Again, the core protein can display"},{"Start":"04:30.770 ","End":"04:35.605","Text":"different heparan sulfate structures when synthesized in different cell types."},{"Start":"04:35.605 ","End":"04:40.180","Text":"The S domains, the regions rich in sulfated sugars,"},{"Start":"04:40.180 ","End":"04:41.695","Text":"the green portions,"},{"Start":"04:41.695 ","End":"04:44.604","Text":"this is an example of an S domain,"},{"Start":"04:44.604 ","End":"04:47.560","Text":"binds specifically to extracellular proteins"},{"Start":"04:47.560 ","End":"04:51.980","Text":"and signaling molecules to alter their activities."},{"Start":"04:52.050 ","End":"04:58.210","Text":"The first example as seen here is the change in activity that may"},{"Start":"04:58.210 ","End":"05:04.090","Text":"result from a conformational change in the protein that is induced by the binding."},{"Start":"05:04.090 ","End":"05:06.940","Text":"Look here we have, a, you have"},{"Start":"05:06.940 ","End":"05:11.455","Text":"a conformational change induced in the protein antithrombin AT,"},{"Start":"05:11.455 ","End":"05:15.728","Text":"this is the protein on binding a specific pentasaccharide,"},{"Start":"05:15.728 ","End":"05:22.265","Text":"remember penta refers to the number of the carbons in this saccharide."},{"Start":"05:22.265 ","End":"05:26.240","Text":"When it binds a specific pentasaccharide S domain,"},{"Start":"05:26.240 ","End":"05:29.770","Text":"right here, right here, binds this,"},{"Start":"05:29.770 ","End":"05:33.140","Text":"it allows its interaction with factor Xa,"},{"Start":"05:33.140 ","End":"05:34.955","Text":"which is what you see here,"},{"Start":"05:34.955 ","End":"05:38.435","Text":"a blood clotting factor preventing clotting."},{"Start":"05:38.435 ","End":"05:45.395","Text":"What ends up happening is you have this protein AT binds this S domain."},{"Start":"05:45.395 ","End":"05:52.640","Text":"This allows factor Xa because there\u0027s a conformational change that happens"},{"Start":"05:52.640 ","End":"05:54.646","Text":"to this AT upon binding"},{"Start":"05:54.646 ","End":"05:59.719","Text":"the pentasaccharide S domain now have instead of a square or a rectangle,"},{"Start":"05:59.719 ","End":"06:04.290","Text":"it actually is a rectangle with a little triangle top,"},{"Start":"06:04.290 ","End":"06:06.885","Text":"so it\u0027s like a house shape."},{"Start":"06:06.885 ","End":"06:11.630","Text":"So you have this binding creates a conformational change of"},{"Start":"06:11.630 ","End":"06:16.820","Text":"the AT protein which now allows factor Xa that has this triangular opening,"},{"Start":"06:16.820 ","End":"06:20.030","Text":"this Pac-Man shape to bind to the AT."},{"Start":"06:20.030 ","End":"06:23.420","Text":"Now the shapes are just to signify or illustrate what we were talking about."},{"Start":"06:23.420 ","End":"06:25.760","Text":"This is not actually the shapes that we will find for"},{"Start":"06:25.760 ","End":"06:28.355","Text":"this protein and this factor in the cells."},{"Start":"06:28.355 ","End":"06:31.235","Text":"Now, another possibility is that"},{"Start":"06:31.235 ","End":"06:35.628","Text":"it may be due to enhancing protein-protein interactions,"},{"Start":"06:35.628 ","End":"06:39.020","Text":"as we see in B you have an example of"},{"Start":"06:39.020 ","End":"06:45.485","Text":"enhanced protein-protein interaction where you have binding of antithrombin AT again"},{"Start":"06:45.485 ","End":"06:50.179","Text":"here to 2 adjacent S domains bring"},{"Start":"06:50.179 ","End":"06:52.880","Text":"the tow proteins in close proximity"},{"Start":"06:52.880 ","End":"06:57.155","Text":"favoring their interaction which inhibits blood clotting."},{"Start":"06:57.155 ","End":"07:02.560","Text":"You have the anti-thrombin protein that is binding and with"},{"Start":"07:02.560 ","End":"07:08.180","Text":"the thrombin that it binds to it and covers 2 S domains,"},{"Start":"07:08.180 ","End":"07:15.225","Text":"so binding of AT and thrombin here to 2 adjacent S domains."},{"Start":"07:15.225 ","End":"07:20.080","Text":"This is the S domain, allows the tow proteins into"},{"Start":"07:20.080 ","End":"07:26.975","Text":"close proximity favoring their interaction which inhibits blood clotting."},{"Start":"07:26.975 ","End":"07:31.679","Text":"These 2 ways result in blood clotting,"},{"Start":"07:31.679 ","End":"07:39.785","Text":"1 with a conformational change and 1 with actually spanning 2 S domains."},{"Start":"07:39.785 ","End":"07:43.385","Text":"The other option is that it may be due to the ability of"},{"Start":"07:43.385 ","End":"07:47.780","Text":"adjacent domains of heparan sulfate to bind"},{"Start":"07:47.780 ","End":"07:50.300","Text":"to 2 different proteins bringing them into"},{"Start":"07:50.300 ","End":"07:55.820","Text":"close proximity and enhancing protein-protein interactions."},{"Start":"07:55.820 ","End":"08:03.950","Text":"This is here, and this allows to interact with the thrombin and they interact with each"},{"Start":"08:03.950 ","End":"08:12.260","Text":"other by bringing these 2 into close proximity because this bound this and this."},{"Start":"08:12.260 ","End":"08:16.130","Text":"A third general mechanism of action is the binding"},{"Start":"08:16.130 ","End":"08:20.090","Text":"of extracellular signal molecules, growth factors,"},{"Start":"08:20.090 ","End":"08:24.770","Text":"for example, to heparan sulfate which increases"},{"Start":"08:24.770 ","End":"08:27.020","Text":"their local concentrations and enhances"},{"Start":"08:27.020 ","End":"08:30.635","Text":"their interaction with growth factor receptors in the cell surface."},{"Start":"08:30.635 ","End":"08:34.100","Text":"In this case, the heparan sulfate acts as a co-receptor."},{"Start":"08:34.100 ","End":"08:39.420","Text":"For example, fibroblast growth factor, FGF."},{"Start":"08:39.420 ","End":"08:43.145","Text":"FGF stands for fibroblast."},{"Start":"08:43.145 ","End":"08:50.255","Text":"This is a type of molecule of cell growth factor,"},{"Start":"08:50.255 ","End":"08:55.685","Text":"is an extracellular protein signal that stimulates cell division."},{"Start":"08:55.685 ","End":"08:57.800","Text":"It first binds to"},{"Start":"08:57.800 ","End":"09:03.765","Text":"heparan sulfate moieties of syndecan molecules in the target cells\u0027 plasma membrane."},{"Start":"09:03.765 ","End":"09:08.330","Text":"Syndecan then presents FGF to"},{"Start":"09:08.330 ","End":"09:12.410","Text":"the FGF plasma membrane receptor and only"},{"Start":"09:12.410 ","End":"09:17.045","Text":"then can FGF interact productively with its receptor to trigger cell division."},{"Start":"09:17.045 ","End":"09:20.480","Text":"What we see in c,"},{"Start":"09:20.480 ","End":"09:26.755","Text":"right here is an example of the third general mechanism where"},{"Start":"09:26.755 ","End":"09:29.890","Text":"binding extracellular signal molecules"},{"Start":"09:29.890 ","End":"09:34.120","Text":"result in binding to heparan sulfate to act as a co-receptor."},{"Start":"09:34.120 ","End":"09:38.590","Text":"You see the S domains of the heparan sulfate they interact with"},{"Start":"09:38.590 ","End":"09:44.530","Text":"both the fibroblast growth factor here and its receptor here,"},{"Start":"09:44.530 ","End":"09:46.660","Text":"the FGF receptor dimer,"},{"Start":"09:46.660 ","End":"09:49.270","Text":"which is in dimers because there\u0027s 2 of them,"},{"Start":"09:49.270 ","End":"09:52.525","Text":"which is within the plasma membrane bringing"},{"Start":"09:52.525 ","End":"09:55.390","Text":"the oligomeric complex together and"},{"Start":"09:55.390 ","End":"09:59.320","Text":"increasing the effectiveness of a low concentration of FGF,"},{"Start":"09:59.320 ","End":"10:02.665","Text":"basically assuring that even though there\u0027s low concentration,"},{"Start":"10:02.665 ","End":"10:08.255","Text":"it finds its way to the receptor in the plasma membrane."},{"Start":"10:08.255 ","End":"10:11.570","Text":"Now finally, we have cases where"},{"Start":"10:11.570 ","End":"10:15.440","Text":"the S domains interact electrostatically in otherwise with a"},{"Start":"10:15.440 ","End":"10:18.230","Text":"variety of soluble molecules outside"},{"Start":"10:18.230 ","End":"10:23.615","Text":"the cell maintaining high local concentrations at the cell surface."},{"Start":"10:23.615 ","End":"10:28.880","Text":"What we see here is d, within heparan sulfate,"},{"Start":"10:28.880 ","End":"10:34.580","Text":"you have cell surface localization or concentration of"},{"Start":"10:34.580 ","End":"10:39.695","Text":"soluble molecules outside the cell to"},{"Start":"10:39.695 ","End":"10:44.700","Text":"the cell surface so you have the high density of negative charges in heparan sulfate,"},{"Start":"10:44.700 ","End":"10:47.198","Text":"we mentioned that it\u0027s from the different sulfates, etc.,"},{"Start":"10:47.198 ","End":"10:52.250","Text":"brings positively charged molecules of lipoprotein lipase,"},{"Start":"10:52.250 ","End":"10:57.860","Text":"for example, here into the vicinity and holds them by electrostatic interactions."},{"Start":"10:57.860 ","End":"11:01.145","Text":"So it comes here and now because of the positive charge"},{"Start":"11:01.145 ","End":"11:05.498","Text":"versus the negative charge of the heparan and a positive of lipoprotein,"},{"Start":"11:05.498 ","End":"11:09.050","Text":"they interact and are held together by"},{"Start":"11:09.050 ","End":"11:11.600","Text":"this electrostatic interaction as well as by"},{"Start":"11:11.600 ","End":"11:15.725","Text":"sequence-specific interactions with S domains."},{"Start":"11:15.725 ","End":"11:20.060","Text":"Such interactions are also central in the first step in"},{"Start":"11:20.060 ","End":"11:25.340","Text":"the entry of certain viruses such as herpes simplex viruses, HSV-1 and HSV-2."},{"Start":"11:25.340 ","End":"11:30.505","Text":"These are both herpes simplex virus that infects humans."},{"Start":"11:30.505 ","End":"11:35.330","Text":"This is also an interaction that allows for"},{"Start":"11:35.330 ","End":"11:40.610","Text":"the first step in entry of certain viruses into cells."},{"Start":"11:40.610 ","End":"11:46.220","Text":"There\u0027s attraction and specific sequence interaction."},{"Start":"11:46.220 ","End":"11:47.960","Text":"Now, the importance of"},{"Start":"11:47.960 ","End":"11:52.880","Text":"correctly synthesized sulfated domains and heparan sulfate and their specificity is"},{"Start":"11:52.880 ","End":"11:56.540","Text":"demonstrated in knockout mice that lack the enzyme that"},{"Start":"11:56.540 ","End":"12:00.485","Text":"places sulfates at the C2 hydroxyl of IdoA."},{"Start":"12:00.485 ","End":"12:04.585","Text":"Remember we said that IdoA will be sulfated at C2."},{"Start":"12:04.585 ","End":"12:07.760","Text":"Such animals are born without kidneys and with"},{"Start":"12:07.760 ","End":"12:11.870","Text":"very severe abnormalities and development of the skeleton eyes."},{"Start":"12:11.870 ","End":"12:17.570","Text":"Meaning these sequences and these different sulfated domains and the heparan sulfate play"},{"Start":"12:17.570 ","End":"12:23.870","Text":"different roles and are super important for the growth,"},{"Start":"12:23.870 ","End":"12:29.060","Text":"the development, the diversity of an organism."},{"Start":"12:29.060 ","End":"12:31.640","Text":"With this, we\u0027ve completed part 2 of proteoglycans"},{"Start":"12:31.640 ","End":"12:33.980","Text":"and talked about the glycan moiety of proteoglycans,"},{"Start":"12:33.980 ","End":"12:36.980","Text":"the sugar portion of proteoglycans and we"},{"Start":"12:36.980 ","End":"12:41.910","Text":"introduced heparan sulfate\u0027s role in the context of proteoglycans."}],"ID":30535},{"Watched":false,"Name":"Proteoglycans Part 3","Duration":"13m 7s","ChapterTopicVideoID":28986,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:02.580","Text":"Welcome to proteoglycans Part 3,"},{"Start":"00:02.580 ","End":"00:06.495","Text":"where we are going to continue talking about proteoglycans,"},{"Start":"00:06.495 ","End":"00:10.980","Text":"and we will introduce proteoglycans aggregates when they actually"},{"Start":"00:10.980 ","End":"00:15.735","Text":"aggregate and the term aggrecan and its significance,"},{"Start":"00:15.735 ","End":"00:21.840","Text":"so this is to summarize that the S domains of the core protein that"},{"Start":"00:21.840 ","End":"00:24.750","Text":"display different heparan sulfate structures in"},{"Start":"00:24.750 ","End":"00:28.560","Text":"different cell types allow for different functions."},{"Start":"00:28.560 ","End":"00:32.030","Text":"These S domains, the region rich and sulfated sugars binds"},{"Start":"00:32.030 ","End":"00:36.140","Text":"specifically to extracellular proteins and signaling molecules to alter"},{"Start":"00:36.140 ","End":"00:40.520","Text":"their activities in the 4 different examples of"},{"Start":"00:40.520 ","End":"00:45.260","Text":"mechanisms of action allowing these actions to occur,"},{"Start":"00:45.260 ","End":"00:47.825","Text":"these binding to occur."},{"Start":"00:47.825 ","End":"00:51.020","Text":"We had the conformational activation or the binding leads to"},{"Start":"00:51.020 ","End":"00:54.620","Text":"conformational change allowing binding,"},{"Start":"00:54.620 ","End":"00:59.095","Text":"and we use the example of antithrombin and thrombin with factor x_a."},{"Start":"00:59.095 ","End":"01:01.280","Text":"Then we have the mechanism"},{"Start":"01:01.280 ","End":"01:03.890","Text":"we\u0027re enhanced protein-protein interaction occurs where you have"},{"Start":"01:03.890 ","End":"01:08.540","Text":"binding antithrombin and thrombin to 2 adjacent S domain,"},{"Start":"01:08.540 ","End":"01:10.765","Text":"so this binds to this."},{"Start":"01:10.765 ","End":"01:13.590","Text":"S-domain and then thrombin binds to"},{"Start":"01:13.590 ","End":"01:18.050","Text":"this S domain and that allows them to interact with each other."},{"Start":"01:18.050 ","End":"01:21.185","Text":"These tow proteins are now close proximity"},{"Start":"01:21.185 ","End":"01:25.040","Text":"and can interact with each other and inhibit blood clotting,"},{"Start":"01:25.040 ","End":"01:31.010","Text":"whereas these 2 different mechanisms result in the same outcome."},{"Start":"01:31.010 ","End":"01:33.620","Text":"We also had the idea of the co-receptor for"},{"Start":"01:33.620 ","End":"01:36.680","Text":"extracellular ligands where we have with the example of"},{"Start":"01:36.680 ","End":"01:43.685","Text":"the fibroblast growth factor the FGF having its receptor on the plasma membrane,"},{"Start":"01:43.685 ","End":"01:46.910","Text":"being that they both bind to the S domain."},{"Start":"01:46.910 ","End":"01:49.040","Text":"This is like a mediator for them,"},{"Start":"01:49.040 ","End":"01:51.980","Text":"and this allows and increases the effectiveness"},{"Start":"01:51.980 ","End":"01:55.880","Text":"of this binding even when there\u0027s low concentration of FGF"},{"Start":"01:55.880 ","End":"01:59.690","Text":"because it will be attracted to the S domain"},{"Start":"01:59.690 ","End":"02:04.625","Text":"to bind the FGF receptors in the plasma membrane."},{"Start":"02:04.625 ","End":"02:06.350","Text":"Last but not least,"},{"Start":"02:06.350 ","End":"02:09.980","Text":"we have the mechanism or we mentioned that self service localization or"},{"Start":"02:09.980 ","End":"02:15.380","Text":"concentration happens as a result of the charges of the heparan sulfate,"},{"Start":"02:15.380 ","End":"02:21.060","Text":"which is negatively charged and positively charged molecules like lipoprotein lipase,"},{"Start":"02:21.060 ","End":"02:24.830","Text":"and then this brings them into the vicinity and holds them by"},{"Start":"02:24.830 ","End":"02:27.830","Text":"the electrostatic interactions as well as by sequence"},{"Start":"02:27.830 ","End":"02:31.580","Text":"specific interactions with S domains of the heparin sulfate,"},{"Start":"02:31.580 ","End":"02:36.425","Text":"and such interactions therefore allow for localization of"},{"Start":"02:36.425 ","End":"02:38.960","Text":"these molecules or concentration to"},{"Start":"02:38.960 ","End":"02:42.950","Text":"a certain vicinity and is also seen as a mechanism of entry,"},{"Start":"02:42.950 ","End":"02:47.150","Text":"first step of entry for certain viruses with herpes simplex,"},{"Start":"02:47.150 ","End":"02:48.920","Text":"mentioned as an example."},{"Start":"02:48.920 ","End":"02:51.350","Text":"Going back to the idea of proteoglycans,"},{"Start":"02:51.350 ","End":"02:54.380","Text":"glycosaminoglycans containing macromolecules of"},{"Start":"02:54.380 ","End":"02:56.935","Text":"the cell surface and extracellular matrix."},{"Start":"02:56.935 ","End":"02:59.570","Text":"We want to talk about that some proteoglycans can form."},{"Start":"02:59.570 ","End":"03:03.320","Text":"Proteoglycans aggregates enormous super molecular assemblies of"},{"Start":"03:03.320 ","End":"03:09.185","Text":"many core proteins all bound to a single molecule of hyaluronate."},{"Start":"03:09.185 ","End":"03:13.460","Text":"The proteoglycan aggregate is the major structural components of"},{"Start":"03:13.460 ","End":"03:18.905","Text":"the extracellular matrix of the cartilage composed of aggrecan,"},{"Start":"03:18.905 ","End":"03:22.430","Text":"hyaluronan, and link protein."},{"Start":"03:22.430 ","End":"03:27.920","Text":"In other words, proteoglycan aggregates are a large aggregation of proteoglycans,"},{"Start":"03:27.920 ","End":"03:33.125","Text":"non covalently bound to a long molecule of hyaluronic acid"},{"Start":"03:33.125 ","End":"03:38.905","Text":"involved in cross-linking the collagen fibrils of cartilage matrix."},{"Start":"03:38.905 ","End":"03:43.625","Text":"The aggregates provide cartilage with unique gel-like property"},{"Start":"03:43.625 ","End":"03:49.069","Text":"and resistance to distortion through deformation, through water absorption."},{"Start":"03:49.069 ","End":"03:51.950","Text":"What does that mean? We\u0027ll use an example to explain"},{"Start":"03:51.950 ","End":"03:54.890","Text":"this aggrecan core protein with a molecular weight"},{"Start":"03:54.890 ","End":"04:00.605","Text":"of about 250,000 has multiple chains of chondroitin sulfate and keratan sulfate."},{"Start":"04:00.605 ","End":"04:02.930","Text":"Remember we mentioned, explain these in previous lesson."},{"Start":"04:02.930 ","End":"04:05.810","Text":"If you remember, keratin sulfate is a little different from the other ones,"},{"Start":"04:05.810 ","End":"04:08.825","Text":"try to remember why or go back to that lesson,"},{"Start":"04:08.825 ","End":"04:12.320","Text":"and these are joined to the core protein to give an aggrecan monomer"},{"Start":"04:12.320 ","End":"04:17.625","Text":"of molecular weight of about 2 million."},{"Start":"04:17.625 ","End":"04:26.050","Text":"We went from 250,000 which would be 2.5 times 10^5,"},{"Start":"04:26.050 ","End":"04:33.145","Text":"to basically a magnitude higher molecular weight of 2 times 10^6."},{"Start":"04:33.145 ","End":"04:39.635","Text":"Aggrecan is a multi-model molecule expressed by chondrocytes specific cells."},{"Start":"04:39.635 ","End":"04:43.940","Text":"Its core protein is composed of 3 globular domains,"},{"Start":"04:43.940 ","End":"04:48.485","Text":"G_1, G_2 and guess what,"},{"Start":"04:48.485 ","End":"04:51.980","Text":"G_3, a large extended region,"},{"Start":"04:51.980 ","End":"04:59.070","Text":"which is CS, between G_2 and G_3."},{"Start":"04:59.440 ","End":"05:04.505","Text":"Which allows glycosaminoglycans chain attachment."},{"Start":"05:04.505 ","End":"05:09.410","Text":"Again, aggrecan is in multi-arm modular molecule expressed by chondrocytes."},{"Start":"05:09.410 ","End":"05:12.020","Text":"Its core protein is composed of 3 globular domains,"},{"Start":"05:12.020 ","End":"05:15.145","Text":"G_1, G_2, and G_3,"},{"Start":"05:15.145 ","End":"05:18.680","Text":"with a large extended regions CS between"},{"Start":"05:18.680 ","End":"05:23.090","Text":"the domains G_2 and G_3 for the glycosaminoglycan chain attachment."},{"Start":"05:23.090 ","End":"05:27.230","Text":"G_1 comprises the amino terminus of the core protein,"},{"Start":"05:27.230 ","End":"05:29.720","Text":"so you have here the amino terminus,"},{"Start":"05:29.720 ","End":"05:33.080","Text":"the NH terminus of the core protein."},{"Start":"05:33.080 ","End":"05:35.060","Text":"Aggrecan is therefore,"},{"Start":"05:35.060 ","End":"05:39.935","Text":"also known as cartilage specific proteoglycan core protein,"},{"Start":"05:39.935 ","End":"05:43.375","Text":"chondroitin sulfate proteoglycan 1,"},{"Start":"05:43.375 ","End":"05:47.210","Text":"aggregating chondroitin sulfate proteoglycan and is a member of"},{"Start":"05:47.210 ","End":"05:52.130","Text":"the aggrecan versican proteoglycan family of extracellular matrix protein."},{"Start":"05:52.130 ","End":"05:57.245","Text":"It is the major proteoglycan and articular cartilage with"},{"Start":"05:57.245 ","End":"06:02.610","Text":"as much as 10 percent of the dry weight of some cartilages being aggrecan,"},{"Start":"06:02.610 ","End":"06:12.155","Text":"so this is to say that aggrecan is also known as cartilage specific proteoglycan or"},{"Start":"06:12.155 ","End":"06:21.750","Text":"chondroitin sulfate proteoglycan 1"},{"Start":"06:22.160 ","End":"06:30.850","Text":"or aggregating chondroitin sulfate proteoglycan."},{"Start":"06:30.850 ","End":"06:33.280","Text":"Say that 3 times in a row,"},{"Start":"06:33.280 ","End":"06:39.200","Text":"and is a member of aggrecan,"},{"Start":"06:39.210 ","End":"06:47.710","Text":"versican proteoglycan family and"},{"Start":"06:47.710 ","End":"06:53.485","Text":"again it is the main proteoglycan in articular cartilage,"},{"Start":"06:53.485 ","End":"07:02.045","Text":"as much as almost 10 percent of dry weight of some cartilages is aggrecan."},{"Start":"07:02.045 ","End":"07:06.365","Text":"When a 100 or more of these decorated core proteins."},{"Start":"07:06.365 ","End":"07:08.675","Text":"Core proteins that have all these additions bind"},{"Start":"07:08.675 ","End":"07:15.470","Text":"a single extended molecule of hyaluronate seen here."},{"Start":"07:15.470 ","End":"07:23.285","Text":"The resulting proteoglycans aggregate has a molecular weight of about 2 times 10^8."},{"Start":"07:23.285 ","End":"07:28.595","Text":"Where before you mentioned 2 times 10^6,"},{"Start":"07:28.595 ","End":"07:31.265","Text":"which means 2 million here."},{"Start":"07:31.265 ","End":"07:36.575","Text":"When they are bound to a single extended molecule of hyaluronate,"},{"Start":"07:36.575 ","End":"07:42.225","Text":"the proteoglycan aggregate can reach up to 2 times 10^ 8,"},{"Start":"07:42.225 ","End":"07:46.490","Text":"and its associated water of hydration occupy"},{"Start":"07:46.490 ","End":"07:51.290","Text":"a volume of about equal to that of a bacterial cell."},{"Start":"07:51.290 ","End":"07:58.815","Text":"Basically means equals the volume that a bacterial cell takes up."},{"Start":"07:58.815 ","End":"08:03.560","Text":"What we see here is the proteoglycan aggregate of"},{"Start":"08:03.560 ","End":"08:08.135","Text":"the extracellular matrix with 1 very long molecule of hyaluronate,"},{"Start":"08:08.135 ","End":"08:09.890","Text":"which is associated,"},{"Start":"08:09.890 ","End":"08:12.320","Text":"and you have hyaluronan right here,"},{"Start":"08:12.320 ","End":"08:15.125","Text":"up to 50,000 repeating disaccharides."},{"Start":"08:15.125 ","End":"08:17.130","Text":"This right here,"},{"Start":"08:17.130 ","End":"08:19.565","Text":"and then you have the enlargement,"},{"Start":"08:19.565 ","End":"08:22.954","Text":"the aggrecan core protein over here attached"},{"Start":"08:22.954 ","End":"08:27.530","Text":"to this extended long molecule of hyaluronate,"},{"Start":"08:27.530 ","End":"08:34.010","Text":"and it is associated non-covalently with about a 100 molecules of the core protein,"},{"Start":"08:34.010 ","End":"08:36.800","Text":"right this right here, the core protein,"},{"Start":"08:36.800 ","End":"08:39.140","Text":"as seen here in the enlargement,"},{"Start":"08:39.140 ","End":"08:41.030","Text":"and each core protein,"},{"Start":"08:41.030 ","End":"08:47.140","Text":"aggrecan contains many covalently bound chondroitin sulfate,"},{"Start":"08:47.140 ","End":"08:51.455","Text":"these red hairs and keratin sulfate chains,"},{"Start":"08:51.455 ","End":"08:56.359","Text":"the blue fibers here that these hairs and these linked proteins"},{"Start":"08:56.359 ","End":"09:01.535","Text":"situated at the junction between each core protein and the hyaluronate backbone,"},{"Start":"09:01.535 ","End":"09:04.675","Text":"which mediate the core protein hyaluronate interaction,"},{"Start":"09:04.675 ","End":"09:06.330","Text":"so again, what we see here,"},{"Start":"09:06.330 ","End":"09:09.425","Text":"is a very long molecule of hyaluronate associated"},{"Start":"09:09.425 ","End":"09:13.189","Text":"non-covalently with about a 100 molecules of the core protein aggrecan."},{"Start":"09:13.189 ","End":"09:15.620","Text":"Each aggrecan molecule contains"},{"Start":"09:15.620 ","End":"09:19.030","Text":"many covalently bound chondroitin sulfate and keratan sulfate chains,"},{"Start":"09:19.030 ","End":"09:25.700","Text":"and linked proteins situated at the junction between each core protein right here,"},{"Start":"09:25.700 ","End":"09:30.695","Text":"is linked proteins that are in the junction between the core protein"},{"Start":"09:30.695 ","End":"09:35.270","Text":"and the hyaluronate backbone mediate the core protein have hyaluronate interaction."},{"Start":"09:35.270 ","End":"09:40.475","Text":"They mediate this interaction between a core protein and the hyaluronate."},{"Start":"09:40.475 ","End":"09:48.605","Text":"Aggrecan interacts strongly with collagen and extracellular matrix of cartilage,"},{"Start":"09:48.605 ","End":"09:55.205","Text":"contributing to the development and tensile strength of this connective tissue."},{"Start":"09:55.205 ","End":"09:59.045","Text":"Interwoven with these enormous extracellular proteoglycans"},{"Start":"09:59.045 ","End":"10:02.165","Text":"are fibrous matrix proteins such as collagen,"},{"Start":"10:02.165 ","End":"10:05.525","Text":"elastin and fibronectin, forming"},{"Start":"10:05.525 ","End":"10:07.610","Text":"a cross-linked meshwork that gives"},{"Start":"10:07.610 ","End":"10:10.955","Text":"the whole extracellular matrix strength and resilience."},{"Start":"10:10.955 ","End":"10:14.500","Text":"Some of these proteins are multi-adhesive,"},{"Start":"10:14.500 ","End":"10:19.385","Text":"a single protein having binding sites for several different matrix molecules."},{"Start":"10:19.385 ","End":"10:22.910","Text":"For example, we have fibronectin,"},{"Start":"10:22.910 ","End":"10:29.510","Text":"which is an example where it has separate domains that bind fibrin, heparan sulfate,"},{"Start":"10:29.510 ","End":"10:34.130","Text":"collagen, and a family of plasma membrane proteins called"},{"Start":"10:34.130 ","End":"10:39.980","Text":"integrins that mediates signaling between the cell interior and extracellular matrix,"},{"Start":"10:39.980 ","End":"10:44.045","Text":"so again, if we look at this figure that we had introduced earlier,"},{"Start":"10:44.045 ","End":"10:52.985","Text":"you have the fibronectin that is bound and you have heparan sulfate, you have collagen,"},{"Start":"10:52.985 ","End":"10:55.025","Text":"and you have the integrins,"},{"Start":"10:55.025 ","End":"11:00.350","Text":"which in turn have binding sites for a number of other extracellular macromolecules,"},{"Start":"11:00.350 ","End":"11:04.580","Text":"and you see here fibronectin bound to the integrins."},{"Start":"11:04.580 ","End":"11:08.245","Text":"The heparan sulfate is this red link here."},{"Start":"11:08.245 ","End":"11:10.335","Text":"This is our heparan sulfate,"},{"Start":"11:10.335 ","End":"11:13.685","Text":"so it also is associated here."},{"Start":"11:13.685 ","End":"11:18.095","Text":"This fibronectin that has separate domains,"},{"Start":"11:18.095 ","End":"11:20.120","Text":"allows it to bind fibrin."},{"Start":"11:20.120 ","End":"11:25.220","Text":"It allows it to bind heparan sulfate, the red collagen."},{"Start":"11:25.220 ","End":"11:30.280","Text":"These booths spirals that are going through and the integrins,"},{"Start":"11:30.280 ","End":"11:33.724","Text":"and this is what mediates the signaling between"},{"Start":"11:33.724 ","End":"11:39.380","Text":"the cell interior down here and the extracellular matrix,"},{"Start":"11:39.380 ","End":"11:41.780","Text":"which is this right here."},{"Start":"11:41.780 ","End":"11:46.790","Text":"The overall view of cell matrix interactions that emerges"},{"Start":"11:46.790 ","End":"11:52.490","Text":"depict an array of interactions between cellular and extracellular molecules."},{"Start":"11:52.490 ","End":"11:58.235","Text":"These interactions serve not merely to anchor cells to the extracellular matrix,"},{"Start":"11:58.235 ","End":"12:03.815","Text":"but also to provide paths that direct the migration of cells in developing"},{"Start":"12:03.815 ","End":"12:07.370","Text":"tissue and through integrins to convey"},{"Start":"12:07.370 ","End":"12:11.210","Text":"information in both directions across the plasma membrane."},{"Start":"12:11.210 ","End":"12:14.750","Text":"See how the integrin goes through internally to"},{"Start":"12:14.750 ","End":"12:19.535","Text":"the actin filaments and externally here it can bind to the fibronectin,"},{"Start":"12:19.535 ","End":"12:23.980","Text":"binds different parts of the extracellular matrix."},{"Start":"12:23.980 ","End":"12:25.745","Text":"Again, looking at this figure,"},{"Start":"12:25.745 ","End":"12:28.730","Text":"we are seeing interactions between cells and extracellular matrix with"},{"Start":"12:28.730 ","End":"12:32.735","Text":"association between cells and the proteoglycan of the extracellular matrix."},{"Start":"12:32.735 ","End":"12:35.390","Text":"The proteoglycan being mediated by"},{"Start":"12:35.390 ","End":"12:39.875","Text":"a membrane protein called integrin and by an extracellular protein,"},{"Start":"12:39.875 ","End":"12:47.615","Text":"fibronectin, and this example with binding sites for both integrin and the proteoglycan."},{"Start":"12:47.615 ","End":"12:52.880","Text":"Now note the close association of collagen fibers with a fibronectin and proteoglycan."},{"Start":"12:52.880 ","End":"12:58.640","Text":"See collagen, it\u0027s associating closely with these."},{"Start":"12:58.640 ","End":"13:03.125","Text":"Now this, we completed the lesson on proteoglycans within glycoconjugates,"},{"Start":"13:03.125 ","End":"13:08.010","Text":"and we learned about proteoglycans and their significance."}],"ID":30536},{"Watched":false,"Name":"Exercise 4","Duration":"3m 5s","ChapterTopicVideoID":28987,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.370","Text":"We\u0027re within proteoglycans and we have moved into the exercises."},{"Start":"00:05.370 ","End":"00:08.520","Text":"Fill in the blanks for the following sentences."},{"Start":"00:08.520 ","End":"00:10.920","Text":"Matrix mammalian cells can produce"},{"Start":"00:10.920 ","End":"00:16.380","Text":"at least blank types of molecules that are members of the blank superfamily."},{"Start":"00:16.380 ","End":"00:20.835","Text":"2. These molecules act as tissue blank,"},{"Start":"00:20.835 ","End":"00:22.995","Text":"influenced the development of specialized tissues,"},{"Start":"00:22.995 ","End":"00:25.125","Text":"mediate the activities of various growth factors,"},{"Start":"00:25.125 ","End":"00:28.350","Text":"and regulate the extracellular assembly of collagen fibrils."},{"Start":"00:28.350 ","End":"00:33.450","Text":"3. The basic proteoglycan unit consists of a,"},{"Start":"00:33.450 ","End":"00:37.470","Text":"blank protein with covalently attached blank."},{"Start":"00:37.470 ","End":"00:40.785","Text":"Let\u0027s think back to the lesson."},{"Start":"00:40.785 ","End":"00:44.675","Text":"Matrix mammalian cells can produce"},{"Start":"00:44.675 ","End":"00:51.245","Text":"at least how many types of molecules that are members of the what superfamily?"},{"Start":"00:51.245 ","End":"00:53.165","Text":"What are we actually talking about?"},{"Start":"00:53.165 ","End":"00:58.445","Text":"You\u0027re talking in this lesson about hint,"},{"Start":"00:58.445 ","End":"01:01.610","Text":"and we mentioned of variety,"},{"Start":"01:01.610 ","End":"01:03.830","Text":"a plethora of types of molecules."},{"Start":"01:03.830 ","End":"01:04.940","Text":"Let\u0027s go into our answer,"},{"Start":"01:04.940 ","End":"01:08.300","Text":"and our first answer would be with starting with matrix mammalian cells can produce"},{"Start":"01:08.300 ","End":"01:11.900","Text":"at least 30 types of molecules that are members of the,"},{"Start":"01:11.900 ","End":"01:15.730","Text":"was the lesson on proteoglycan superfamily."},{"Start":"01:15.730 ","End":"01:22.420","Text":"2. These molecules act as tissue what,"},{"Start":"01:22.420 ","End":"01:28.235","Text":"a function that influenced the development of specialized tissues,"},{"Start":"01:28.235 ","End":"01:31.130","Text":"mediate the activities of various growth factors and"},{"Start":"01:31.130 ","End":"01:34.490","Text":"regulate the extracellular assembly of collagen fibrils,"},{"Start":"01:34.490 ","End":"01:40.445","Text":"so proteoglycans, these molecules act as tissue organizers."},{"Start":"01:40.445 ","End":"01:42.590","Text":"They influenced the development of specialized tissue,"},{"Start":"01:42.590 ","End":"01:44.750","Text":"mediate the activities of various growth factors and"},{"Start":"01:44.750 ","End":"01:47.980","Text":"regulate the extracellular assembly of collagen fibrils."},{"Start":"01:47.980 ","End":"01:54.800","Text":"3. The basic proteoglycan unit consists of a something protein with"},{"Start":"01:54.800 ","End":"02:02.900","Text":"covalently attached something that we also gave a short way of expressing it."},{"Start":"02:02.900 ","End":"02:09.185","Text":"The basic proteoglycan unit consists of what protein and in what protein?"},{"Start":"02:09.185 ","End":"02:12.500","Text":"It is a core protein."},{"Start":"02:12.500 ","End":"02:18.980","Text":"The basic proteoglycan unit consists of a core protein with"},{"Start":"02:18.980 ","End":"02:26.255","Text":"covalently attached glycosaminoglycans which we also know as GAGs."},{"Start":"02:26.255 ","End":"02:29.875","Text":"Let\u0027s go over these sentences."},{"Start":"02:29.875 ","End":"02:33.165","Text":"We completed a lesson on proteoglycans,"},{"Start":"02:33.165 ","End":"02:36.890","Text":"and within it we learned that the matrix mammalian cells can produce"},{"Start":"02:36.890 ","End":"02:41.180","Text":"at least 30 types of molecules that are members of the proteoglycans superfamily."},{"Start":"02:41.180 ","End":"02:43.520","Text":"These molecules act as tissue organizers"},{"Start":"02:43.520 ","End":"02:45.900","Text":"influence the development of specialized tissues and mediate"},{"Start":"02:45.900 ","End":"02:48.320","Text":"the activities of various growth factors as well as"},{"Start":"02:48.320 ","End":"02:51.155","Text":"regulate the extracellular assembly of collagen fibrils."},{"Start":"02:51.155 ","End":"02:56.015","Text":"The basic proteoglycan unit consists of a core protein with covalently attached GAGs,"},{"Start":"02:56.015 ","End":"03:01.220","Text":"glycosaminoglycans or just 1 GAG, glycosaminoglycan."},{"Start":"03:01.220 ","End":"03:06.330","Text":"With that we completed our first exercise within proteoglycans."}],"ID":30537},{"Watched":false,"Name":"Exercise 5","Duration":"42s","ChapterTopicVideoID":28988,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.110","Text":"Welcome to another exercise within proteoglycans."},{"Start":"00:04.110 ","End":"00:06.225","Text":"Define a proteoglycan."},{"Start":"00:06.225 ","End":"00:09.960","Text":"Proteoglycans are proteins that are heavily glycosylated."},{"Start":"00:09.960 ","End":"00:12.600","Text":"Proteo, protein,"},{"Start":"00:12.600 ","End":"00:16.080","Text":"glycans, glycosylated,"},{"Start":"00:16.080 ","End":"00:17.940","Text":"and glycans are sugars."},{"Start":"00:17.940 ","End":"00:20.790","Text":"The basic proteoglycan unit consists of a core protein with"},{"Start":"00:20.790 ","End":"00:25.605","Text":"1 or more covalently attached glycosaminoglycans chain or chains."},{"Start":"00:25.605 ","End":"00:30.270","Text":"The short for glycosaminoglycan as mentioned is GAG."},{"Start":"00:30.270 ","End":"00:34.260","Text":"A proteoglycan is a protein that is heavily glycosylated and"},{"Start":"00:34.260 ","End":"00:42.070","Text":"its basic unit consists of a core protein with 1 or more covalently attached GAG or GAGs."}],"ID":30538},{"Watched":false,"Name":"Exercise 6","Duration":"2m 28s","ChapterTopicVideoID":28989,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.470","Text":"Welcome back to another exercise on proteoglycans."},{"Start":"00:04.470 ","End":"00:07.170","Text":"How do proteoglycans attract water to"},{"Start":"00:07.170 ","End":"00:11.200","Text":"the extracellular matrix for compression resistance?"},{"Start":"00:11.480 ","End":"00:14.340","Text":"The basic proteoglycan unit consists of"},{"Start":"00:14.340 ","End":"00:18.195","Text":"a core protein with covalently attached glycosaminoglycans."},{"Start":"00:18.195 ","End":"00:23.775","Text":"These GAGs play a significant role in the ability"},{"Start":"00:23.775 ","End":"00:29.549","Text":"of the proteoglycans to attract water so that it has compression resistance."},{"Start":"00:29.549 ","End":"00:36.300","Text":"What contributes to this in the GAGs is because GAGs are"},{"Start":"00:36.300 ","End":"00:39.630","Text":"highly negatively charged because of sulfate or carboxyl groups on"},{"Start":"00:39.630 ","End":"00:43.610","Text":"most of their sugars and these have a negative charge."},{"Start":"00:43.610 ","End":"00:47.570","Text":"Their highly negative charge attracts osmotically active cations,"},{"Start":"00:47.570 ","End":"00:51.695","Text":"positively charged ions, like sodium ions,"},{"Start":"00:51.695 ","End":"00:55.150","Text":"which causes large amounts of water to be incorporated into the matrix."},{"Start":"00:55.150 ","End":"00:58.715","Text":"The minute you have this attraction of ions,"},{"Start":"00:58.715 ","End":"01:03.200","Text":"then water wants to come in because it\u0027s become"},{"Start":"01:03.200 ","End":"01:05.690","Text":"a hypertonic solution so it wants water"},{"Start":"01:05.690 ","End":"01:08.256","Text":"to come in to become more of a hypotonic solution,"},{"Start":"01:08.256 ","End":"01:15.920","Text":"more importantly, to equalize the actual osmolarity across any membranes or any areas."},{"Start":"01:15.920 ","End":"01:19.700","Text":"You have water being attracted into the matrix,"},{"Start":"01:19.700 ","End":"01:22.730","Text":"which then results in pores hydrated shells."},{"Start":"01:22.730 ","End":"01:24.410","Text":"Because of how a matrix is built,"},{"Start":"01:24.410 ","End":"01:27.910","Text":"you have water in it and it becomes a gel-like substance."},{"Start":"01:27.910 ","End":"01:30.770","Text":"This is responsible for the turgor"},{"Start":"01:30.770 ","End":"01:34.895","Text":"that enables the matrix to withstand compressive force."},{"Start":"01:34.895 ","End":"01:39.320","Text":"Now we talked about turgor pressure in an earlier subject with"},{"Start":"01:39.320 ","End":"01:45.000","Text":"regard to plant cells and the cell wall, etc."},{"Start":"01:45.200 ","End":"01:52.600","Text":"Proteoglycans attract water due to the GAGs in the proteoglycans,"},{"Start":"01:52.600 ","End":"01:56.000","Text":"the GAGs that are covalently attached to them that have"},{"Start":"01:56.000 ","End":"02:01.530","Text":"a negative charge and thus attract water."},{"Start":"02:01.530 ","End":"02:06.200","Text":"Since these are in the extracellular matrix that has this structure of"},{"Start":"02:06.200 ","End":"02:12.530","Text":"different fibers and different structures creating the extracellular matrix,"},{"Start":"02:12.530 ","End":"02:16.775","Text":"these water molecules that get trapped in between result in"},{"Start":"02:16.775 ","End":"02:26.579","Text":"a porous gel-like consistency that allows the matrix to withstand compressive force."}],"ID":30539},{"Watched":false,"Name":"Exercise 7","Duration":"4m 16s","ChapterTopicVideoID":28990,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.425","Text":"Let\u0027s dive into another exercise covering the lesson on Proteoglycans."},{"Start":"00:04.425 ","End":"00:06.645","Text":"Part 1, what are S domains?"},{"Start":"00:06.645 ","End":"00:10.560","Text":"The S domains are regions in the proteoglycans that are rich in sulfated sugars,"},{"Start":"00:10.560 ","End":"00:13.590","Text":"and these bind specifically to extracellular proteins and"},{"Start":"00:13.590 ","End":"00:16.950","Text":"signaling molecules to alter their activities."},{"Start":"00:16.950 ","End":"00:20.010","Text":"If you remember, we had introduced a few figures where we"},{"Start":"00:20.010 ","End":"00:23.535","Text":"saw the S domains that are mostly green."},{"Start":"00:23.535 ","End":"00:27.305","Text":"We also talked about their structure,"},{"Start":"00:27.305 ","End":"00:31.595","Text":"how they are of alternating units are disaccharides."},{"Start":"00:31.595 ","End":"00:36.125","Text":"Part 2, how do S domains induce their effect, their function?"},{"Start":"00:36.125 ","End":"00:37.490","Text":"What is the mechanism?"},{"Start":"00:37.490 ","End":"00:41.420","Text":"Again, the S domains or regions and the proteoglycans that are rich and sulfated sugars."},{"Start":"00:41.420 ","End":"00:45.320","Text":"These bind specifically to extracellular proteins and signaling molecules to alter"},{"Start":"00:45.320 ","End":"00:50.980","Text":"their activities in a few different mechanisms of action we actually mentioned for."},{"Start":"00:50.980 ","End":"00:53.900","Text":"The S domains are suggested to alter activities of molecules."},{"Start":"00:53.900 ","End":"00:57.610","Text":"They bind using these mechanisms, 1,"},{"Start":"00:57.610 ","End":"00:59.270","Text":"the change in activity may result from"},{"Start":"00:59.270 ","End":"01:03.755","Text":"a conformational change in the protein that is induced by the binding."},{"Start":"01:03.755 ","End":"01:08.810","Text":"If you remember, we talked about antithrombin and its binding or it has"},{"Start":"01:08.810 ","End":"01:15.725","Text":"a conformational change that allows it to actually bind a different factor."},{"Start":"01:15.725 ","End":"01:16.820","Text":"Now that was just an example."},{"Start":"01:16.820 ","End":"01:21.830","Text":"Think of a figure, but this is 1 way where there is actually a conformational change."},{"Start":"01:21.830 ","End":"01:25.879","Text":"2 it may be due to the ability"},{"Start":"01:25.879 ","End":"01:29.960","Text":"of adjacent domains of heparan sulfate to bind 2 different proteins,"},{"Start":"01:29.960 ","End":"01:33.755","Text":"bringing them into close proximity and enhancing protein-protein interactions."},{"Start":"01:33.755 ","End":"01:40.740","Text":"Again, we use the example of AT antithrombin and it binding on 1 S domain and then throw"},{"Start":"01:40.740 ","End":"01:47.860","Text":"my binding and then it\u0027s binding to the other S domain that\u0027s next to it,"},{"Start":"01:47.860 ","End":"01:49.760","Text":"but spanning both domains,"},{"Start":"01:49.760 ","End":"01:54.619","Text":"allowing this closeness to have a protein-protein interaction."},{"Start":"01:54.619 ","End":"02:01.310","Text":"We gave an example 1 and 2 with the same protein having different effects,"},{"Start":"02:01.310 ","End":"02:07.564","Text":"allowing the same outcome of blood clotting being affected."},{"Start":"02:07.564 ","End":"02:12.844","Text":"3, a third general mechanism of action is the binding of extracellular signal molecules,"},{"Start":"02:12.844 ","End":"02:14.340","Text":"growth factors, for example."},{"Start":"02:14.340 ","End":"02:17.795","Text":"That\u0027s what we actually use an example 2 heparan sulfate,"},{"Start":"02:17.795 ","End":"02:20.510","Text":"which increases their local concentration and enhances"},{"Start":"02:20.510 ","End":"02:23.900","Text":"their interaction with growth factor receptors in the cell surface."},{"Start":"02:23.900 ","End":"02:27.350","Text":"In this case, the heparan sulfate acts as a co-receptor."},{"Start":"02:27.350 ","End":"02:33.305","Text":"Basically what happens is that the heparan sulfate attracts"},{"Start":"02:33.305 ","End":"02:39.515","Text":"extracellular signal molecules and they have a receptor in the membrane."},{"Start":"02:39.515 ","End":"02:45.470","Text":"This actually mediates the interaction between the 2 proteins,"},{"Start":"02:45.470 ","End":"02:51.510","Text":"the extracellular signal molecule and the actual receptor for this molecule."},{"Start":"02:51.510 ","End":"02:58.910","Text":"You have this protein-protein interaction that is enhanced and allows"},{"Start":"02:58.910 ","End":"03:02.210","Text":"for it to occur even if"},{"Start":"03:02.210 ","End":"03:08.405","Text":"the actual extracellular signal molecule is in low concentrations in the cell."},{"Start":"03:08.405 ","End":"03:11.570","Text":"This increase, this enhancement of"},{"Start":"03:11.570 ","End":"03:14.870","Text":"the protein-protein interaction allows for small amounts to"},{"Start":"03:14.870 ","End":"03:21.695","Text":"still be attracted and have their action or their binding facilitated."},{"Start":"03:21.695 ","End":"03:27.140","Text":"Now finally, the fourth mechanism we mentioned is when the estimates"},{"Start":"03:27.140 ","End":"03:30.230","Text":"interact electrostatically and otherwise"},{"Start":"03:30.230 ","End":"03:33.425","Text":"with a variety of soluble molecules outside the cell,"},{"Start":"03:33.425 ","End":"03:36.845","Text":"maintaining high local concentrations at the cell surface."},{"Start":"03:36.845 ","End":"03:42.325","Text":"This we talked about being due to the negative charge that is found"},{"Start":"03:42.325 ","End":"03:49.175","Text":"in the actual proteoglycan as a result of the sulfated sugars,"},{"Start":"03:49.175 ","End":"03:56.510","Text":"allowing positive molecule\u0027s positive proteins to be attracted and with a specific"},{"Start":"03:56.510 ","End":"04:00.275","Text":"sequence to actually be held together"},{"Start":"04:00.275 ","End":"04:04.945","Text":"and thus maintaining their concentration at the cell surface."},{"Start":"04:04.945 ","End":"04:08.120","Text":"These are the 4 we mentioned in the lesson."},{"Start":"04:08.120 ","End":"04:14.285","Text":"We gave figures and examples to explain these and help with a visual aid."},{"Start":"04:14.285 ","End":"04:16.740","Text":"Hopefully, these are clear."}],"ID":30540},{"Watched":false,"Name":"Exercise 8","Duration":"1m 48s","ChapterTopicVideoID":28991,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.020 ","End":"00:03.525","Text":"As we\u0027re testing our knowledge about proteoglycans,"},{"Start":"00:03.525 ","End":"00:05.685","Text":"we are diving into another exercise."},{"Start":"00:05.685 ","End":"00:08.550","Text":"What are proteoglycan aggregates?"},{"Start":"00:08.550 ","End":"00:12.210","Text":"Some proteoglycans can form proteoglycan aggregates."},{"Start":"00:12.210 ","End":"00:15.240","Text":"These are enormous supermolecular assemblies of"},{"Start":"00:15.240 ","End":"00:19.755","Text":"many core proteins all bound to a single molecule of hyaluronate."},{"Start":"00:19.755 ","End":"00:21.840","Text":"The proteoglycan aggregate is"},{"Start":"00:21.840 ","End":"00:24.900","Text":"the major structural component of the extracellular matrix,"},{"Start":"00:24.900 ","End":"00:29.400","Text":"also indicated as ECM, of the cartilage."},{"Start":"00:29.400 ","End":"00:31.700","Text":"The proteoglycan aggregate is"},{"Start":"00:31.700 ","End":"00:36.920","Text":"the major structural component of the ECM of the cartilage composed of aggrecan,"},{"Start":"00:36.920 ","End":"00:40.895","Text":"hyaluronan, and link protein."},{"Start":"00:40.895 ","End":"00:43.805","Text":"The aggregates provide cartilage with"},{"Start":"00:43.805 ","End":"00:48.500","Text":"unique gel-like property and resistance to distortion through water absorption."},{"Start":"00:48.500 ","End":"00:53.870","Text":"This is what we mentioned and explained in general about the extracellular matrix."},{"Start":"00:53.870 ","End":"01:01.340","Text":"We have these aggregates absorbing water and thus giving cartilage gel-like property"},{"Start":"01:01.340 ","End":"01:09.245","Text":"which allows its malleability to help aid in between bones, etc."},{"Start":"01:09.245 ","End":"01:11.125","Text":"In other words,"},{"Start":"01:11.125 ","End":"01:16.745","Text":"proteoglycan aggregates are a large aggregation of proteoglycans non-covalently bound to"},{"Start":"01:16.745 ","End":"01:18.470","Text":"a long molecule of"},{"Start":"01:18.470 ","End":"01:24.950","Text":"hyaluronic acid involved in cross-linking the collagen fibrils of cartilage matrix."},{"Start":"01:24.950 ","End":"01:26.975","Text":"We also had a figure for this,"},{"Start":"01:26.975 ","End":"01:29.720","Text":"so if you want to go back to the lesson to see the figure,"},{"Start":"01:29.720 ","End":"01:31.550","Text":"please feel free to do so,"},{"Start":"01:31.550 ","End":"01:36.050","Text":"but make sure you understand the concept of this attraction of"},{"Start":"01:36.050 ","End":"01:41.960","Text":"water within a matrix structure giving up malleable,"},{"Start":"01:41.960 ","End":"01:47.790","Text":"gel-like property that is super important in different tissues."}],"ID":30541},{"Watched":false,"Name":"Glycoproteins","Duration":"11m 26s","ChapterTopicVideoID":28992,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.440","Text":"Hi there. Welcome back to the lesson within the chapter of glycoconjugates."},{"Start":"00:04.440 ","End":"00:08.445","Text":"In this lesson, we will talk about glycoproteins."},{"Start":"00:08.445 ","End":"00:11.190","Text":"In this section, we will learn about the significance of"},{"Start":"00:11.190 ","End":"00:14.850","Text":"glycoproteins and examples of glycoproteins."},{"Start":"00:14.850 ","End":"00:19.230","Text":"Glycoproteins have covalently attached oligosaccharides."},{"Start":"00:19.230 ","End":"00:21.450","Text":"Yes, these are sugar molecules."},{"Start":"00:21.450 ","End":"00:23.010","Text":"As you see here."},{"Start":"00:23.010 ","End":"00:28.035","Text":"You have a glycoprotein with carbohydrates attached."},{"Start":"00:28.035 ","End":"00:30.570","Text":"Oligosaccharides are carbohydrates."},{"Start":"00:30.570 ","End":"00:33.060","Text":"So this chain here, these little balls,"},{"Start":"00:33.060 ","End":"00:36.270","Text":"these are the oligosaccharides, the carbohydrates."},{"Start":"00:36.270 ","End":"00:40.730","Text":"Glycoproteins are carbohydrate-protein conjugates in which the carbohydrate moieties are"},{"Start":"00:40.730 ","End":"00:45.650","Text":"smaller and more structurally diverse than the glycosaminoglycans of proteoglycans."},{"Start":"00:45.650 ","End":"00:48.515","Text":"We had previously talked about proteoglycans."},{"Start":"00:48.515 ","End":"00:50.570","Text":"Here we are talking about glycoproteins."},{"Start":"00:50.570 ","End":"00:57.045","Text":"These are 2 terms that combined sugar with proteins."},{"Start":"00:57.045 ","End":"01:02.795","Text":"These are both glycoconjugates of protein and sugar,"},{"Start":"01:02.795 ","End":"01:04.250","Text":"but they are different."},{"Start":"01:04.250 ","End":"01:09.949","Text":"As mentioned here, glycoproteins have smaller carbohydrate moieties and are more"},{"Start":"01:09.949 ","End":"01:12.560","Text":"structurally diverse than glycosaminoglycans are"},{"Start":"01:12.560 ","End":"01:16.010","Text":"the proteoglycans because remember we\u0027ve shown the structure of glycosaminoglycans,"},{"Start":"01:16.010 ","End":"01:22.760","Text":"they tend to have specific monomers units that make them up in a specific structure."},{"Start":"01:22.760 ","End":"01:28.355","Text":"What we see here again is a plasma membrane and we have the glycoprotein,"},{"Start":"01:28.355 ","End":"01:33.965","Text":"you have the protein with the oligosaccharides attached, the carbohydrates attached."},{"Start":"01:33.965 ","End":"01:35.960","Text":"The carbohydrate is attached at"},{"Start":"01:35.960 ","End":"01:40.615","Text":"its anomeric carbon 3 glycosidic links to the OH of a serine,"},{"Start":"01:40.615 ","End":"01:43.425","Text":"ser residue or Thr,"},{"Start":"01:43.425 ","End":"01:47.840","Text":"threonine residue and this is an O-linked oligosaccharide or through"},{"Start":"01:47.840 ","End":"01:54.700","Text":"an N glycosyl link versus an O-linked so this is an N-linked."},{"Start":"01:54.700 ","End":"01:57.935","Text":"An N-glycosyl link to the amide nitrogen of"},{"Start":"01:57.935 ","End":"02:03.920","Text":"an ASN residue and N linked to the asparagine residue."},{"Start":"02:03.920 ","End":"02:06.470","Text":"If you see in the figure on the right,"},{"Start":"02:06.470 ","End":"02:09.290","Text":"you see basically an A,"},{"Start":"02:09.290 ","End":"02:12.965","Text":"the O-linked over here and in B,"},{"Start":"02:12.965 ","End":"02:14.780","Text":"you have the N-linked."},{"Start":"02:14.780 ","End":"02:24.050","Text":"So you see them linked either to the OH or to the amine residue."},{"Start":"02:24.050 ","End":"02:27.635","Text":"When it\u0027s to the OH that it was replaced,"},{"Start":"02:27.635 ","End":"02:30.465","Text":"it\u0027s O-linked, and when it\u0027s to the amino group,"},{"Start":"02:30.465 ","End":"02:37.860","Text":"and we know amide nitrogen is an NH,"},{"Start":"02:37.860 ","End":"02:41.905","Text":"then it replaces it over here."},{"Start":"02:41.905 ","End":"02:45.350","Text":"Now, below you see examples as well,"},{"Start":"02:45.350 ","End":"02:49.310","Text":"and I\u0027ll explain figure in more detail in a tad bit."},{"Start":"02:49.310 ","End":"02:52.655","Text":"Some glycoproteins have a single oligosaccharide chain,"},{"Start":"02:52.655 ","End":"02:55.054","Text":"but many have more than 1."},{"Start":"02:55.054 ","End":"02:59.030","Text":"The carbohydrate may constitute from 1 percent to"},{"Start":"02:59.030 ","End":"03:04.095","Text":"70 percent or more of the protein by mass."},{"Start":"03:04.095 ","End":"03:06.980","Text":"You may have a glycoprotein where the protein has"},{"Start":"03:06.980 ","End":"03:10.550","Text":"1 oligosaccharide chain and then it\u0027ll be in the lower,"},{"Start":"03:10.550 ","End":"03:13.020","Text":"1 percent of the protein,"},{"Start":"03:13.020 ","End":"03:17.965","Text":"or up to 70 percent or more of the protein by mass."},{"Start":"03:17.965 ","End":"03:25.070","Text":"This is a huge range and makes this a group vast in its variability."},{"Start":"03:25.070 ","End":"03:30.140","Text":"The structures of a large number of O and N-linked oligosaccharides from a variety of"},{"Start":"03:30.140 ","End":"03:35.585","Text":"glycoproteins are known and shows a few typical examples."},{"Start":"03:35.585 ","End":"03:38.750","Text":"Now, the external surface of the plasma membrane has"},{"Start":"03:38.750 ","End":"03:42.650","Text":"many membrane glycoproteins with arrays of"},{"Start":"03:42.650 ","End":"03:47.560","Text":"covalently attached oligosaccharides of varying complexity."},{"Start":"03:47.560 ","End":"03:50.765","Text":"Let\u0027s go in and explain this figure here."},{"Start":"03:50.765 ","End":"03:56.735","Text":"What we see here are oligosaccharide linkages and glycoproteins."},{"Start":"03:56.735 ","End":"04:00.050","Text":"You have O-linked oligosaccharides showing that they have"},{"Start":"04:00.050 ","End":"04:06.665","Text":"a glycosidic bond to the hydroxyl group of serine or threonine residues,"},{"Start":"04:06.665 ","End":"04:08.870","Text":"and these are shaded in pink."},{"Start":"04:08.870 ","End":"04:13.850","Text":"This can also be here as you see as threonine and this"},{"Start":"04:13.850 ","End":"04:19.310","Text":"is what we\u0027re showing as the shape of these to be either a serine or threonine."},{"Start":"04:19.310 ","End":"04:23.210","Text":"This glycosidic bond, this O-linked oligosaccharide that"},{"Start":"04:23.210 ","End":"04:27.710","Text":"is with a glycosidic that is bound by a glycosidic bond"},{"Start":"04:27.710 ","End":"04:31.760","Text":"to the hydroxyl group of either of these is illustrated here with a gallon"},{"Start":"04:31.760 ","End":"04:35.975","Text":"AC as the sugar at the reducing end of the oligosaccharide."},{"Start":"04:35.975 ","End":"04:37.760","Text":"You see it right here."},{"Start":"04:37.760 ","End":"04:39.580","Text":"As a reminder,"},{"Start":"04:39.580 ","End":"04:41.370","Text":"this is a mouthful."},{"Start":"04:41.370 ","End":"04:42.950","Text":"Like saying in the shorter versions,"},{"Start":"04:42.950 ","End":"04:47.180","Text":"but gallon AC is an N acetyl galactosamine."},{"Start":"04:47.180 ","End":"04:51.470","Text":"Remember it\u0027s a sugar molecule that can recognize and bind to a cell surface proteins,"},{"Start":"04:51.470 ","End":"04:54.020","Text":"so the gallon AC has the sugar,"},{"Start":"04:54.020 ","End":"04:55.700","Text":"the reducing end of the oligosaccharide."},{"Start":"04:55.700 ","End":"04:59.270","Text":"Now, 1 simple chain and 1 complex chain are not."},{"Start":"04:59.270 ","End":"05:07.415","Text":"You have a simple chain in the example and a complex chain below it in the example."},{"Start":"05:07.415 ","End":"05:10.040","Text":"Now, as to these little shapes,"},{"Start":"05:10.040 ","End":"05:12.170","Text":"you have the legend to the right."},{"Start":"05:12.170 ","End":"05:13.775","Text":"You don\u0027t need to memorize it."},{"Start":"05:13.775 ","End":"05:16.370","Text":"The idea is just that it is a chain of"},{"Start":"05:16.370 ","End":"05:23.825","Text":"different sugars that can be made and allows for a great variety of these."},{"Start":"05:23.825 ","End":"05:26.255","Text":"Now if we\u0027re looking to B,"},{"Start":"05:26.255 ","End":"05:29.390","Text":"the N-linked oligosaccharides have an N-glycosidic bond to"},{"Start":"05:29.390 ","End":"05:33.350","Text":"the amid nitrogen of an ASN residue,"},{"Start":"05:33.350 ","End":"05:35.644","Text":"an asparagine residue,"},{"Start":"05:35.644 ","End":"05:39.055","Text":"and this is shaded in green."},{"Start":"05:39.055 ","End":"05:41.660","Text":"It\u0027s illustrated here with a DLC,"},{"Start":"05:41.660 ","End":"05:44.090","Text":"NAC as the terminal sugar."},{"Start":"05:44.090 ","End":"05:46.640","Text":"Now, 3 common types of oligosaccharide chains"},{"Start":"05:46.640 ","End":"05:49.310","Text":"that are N-linked in glycoproteins are shown."},{"Start":"05:49.310 ","End":"05:50.980","Text":"You see 3 of them,"},{"Start":"05:50.980 ","End":"05:53.645","Text":"2 up top and 1 at the bottom."},{"Start":"05:53.645 ","End":"05:55.910","Text":"A complete description of oligosaccharides structure"},{"Start":"05:55.910 ","End":"05:58.790","Text":"requires specification of the position"},{"Start":"05:58.790 ","End":"06:04.595","Text":"and stereochemistry Alpha-Beta of each glycosidic linkage."},{"Start":"06:04.595 ","End":"06:10.010","Text":"Bottom line, what you\u0027re seeing here are 3 examples of different varieties,"},{"Start":"06:10.010 ","End":"06:14.390","Text":"common types of oligosaccharides chains that are N-linked in glycoproteins."},{"Start":"06:14.390 ","End":"06:18.740","Text":"The external surface of the plasma membrane has many membrane glycoproteins."},{"Start":"06:18.740 ","End":"06:21.920","Text":"One of the best-characterized membrane glycoproteins is"},{"Start":"06:21.920 ","End":"06:26.885","Text":"glycophorin A of the erythrocyte membrane."},{"Start":"06:26.885 ","End":"06:35.210","Text":"This contains 60 percent carbohydrate by mass in the form of 16 oligosaccharide chains,"},{"Start":"06:35.210 ","End":"06:39.230","Text":"totaling 60-70 monosaccharide residues covalently"},{"Start":"06:39.230 ","End":"06:43.775","Text":"attached to amino acid residues near the amino terminus of the polypeptide chain,"},{"Start":"06:43.775 ","End":"06:48.800","Text":"15 of the oligosaccharide chains are O-linked to serine or threonine"},{"Start":"06:48.800 ","End":"06:55.020","Text":"residues and 1 is n N-linked to an ASN in asparagine residue."},{"Start":"06:57.020 ","End":"07:01.550","Text":"The external surface of the plasma membrane you see in either of"},{"Start":"07:01.550 ","End":"07:05.925","Text":"these illustrations has many membrane glycoproteins."},{"Start":"07:05.925 ","End":"07:08.225","Text":"You see a glycoprotein here."},{"Start":"07:08.225 ","End":"07:10.460","Text":"You see a glycoprotein here."},{"Start":"07:10.460 ","End":"07:14.240","Text":"Again, the description of what a glycoprotein is is a protein with a carbohydrate"},{"Start":"07:14.240 ","End":"07:20.325","Text":"attached and these are the external part of the membrane."},{"Start":"07:20.325 ","End":"07:26.885","Text":"You will have many of these as you see here and they will have a variety."},{"Start":"07:26.885 ","End":"07:30.185","Text":"Again, glycoprotein, glycoprotein, etc."},{"Start":"07:30.185 ","End":"07:34.640","Text":"Many of the proteins secreted by eukaryotic cells are glycoproteins,"},{"Start":"07:34.640 ","End":"07:37.250","Text":"including most of the proteins of blood."},{"Start":"07:37.250 ","End":"07:41.435","Text":"For example, immunoglobulins, antibodies,"},{"Start":"07:41.435 ","End":"07:45.455","Text":"and certain hormones such as follicle stimulating hormone,"},{"Start":"07:45.455 ","End":"07:49.985","Text":"luteinizing hormone, and thyroid stimulating hormone are glycoproteins."},{"Start":"07:49.985 ","End":"07:53.320","Text":"Many milk proteins, including"},{"Start":"07:53.320 ","End":"07:57.965","Text":"lactalbumin and some of the proteins secreted by the pancreas,"},{"Start":"07:57.965 ","End":"08:01.250","Text":"such as ribonuclease are glycosylated,"},{"Start":"08:01.250 ","End":"08:03.155","Text":"meaning they are glycoproteins,"},{"Start":"08:03.155 ","End":"08:07.110","Text":"as are most of the proteins contained in lysosomes."},{"Start":"08:07.110 ","End":"08:09.965","Text":"What you see here is just a reminder."},{"Start":"08:09.965 ","End":"08:12.380","Text":"This is what antibodies genuine look like"},{"Start":"08:12.380 ","End":"08:16.175","Text":"this white shape and these are examples of glycoproteins."},{"Start":"08:16.175 ","End":"08:19.370","Text":"Now, the same protein produced in 2 types of"},{"Start":"08:19.370 ","End":"08:22.730","Text":"tissues can result in different glycoproteins."},{"Start":"08:22.730 ","End":"08:25.670","Text":"A number of cases are known in which the same protein produced in"},{"Start":"08:25.670 ","End":"08:28.790","Text":"2 types of tissues has different glycosylation patterns."},{"Start":"08:28.790 ","End":"08:32.990","Text":"For example, the human protein interferon 1, IFN1,"},{"Start":"08:32.990 ","End":"08:37.310","Text":"interferon 1 has 1 set of oligosaccharide chains when produced in"},{"Start":"08:37.310 ","End":"08:42.260","Text":"ovarian cells and a different set when produced in breast epithelial cells."},{"Start":"08:42.260 ","End":"08:46.445","Text":"The biological significance of these tissue glycoforms,"},{"Start":"08:46.445 ","End":"08:51.889","Text":"which means any of several different forms of a glycoprotein is not understood."},{"Start":"08:51.889 ","End":"08:53.270","Text":"But in some way,"},{"Start":"08:53.270 ","End":"08:57.845","Text":"the oligosaccharide chains represent a tissue-specific marker,"},{"Start":"08:57.845 ","End":"09:00.560","Text":"something that identifies it,"},{"Start":"09:00.560 ","End":"09:03.095","Text":"it\u0027s an identifier for the tissue."},{"Start":"09:03.095 ","End":"09:05.720","Text":"The biological advantages of adding"},{"Start":"09:05.720 ","End":"09:09.245","Text":"oligosaccharides to proteins are not fully understood."},{"Start":"09:09.245 ","End":"09:13.340","Text":"Very hydrophilic clusters of carbohydrates alter"},{"Start":"09:13.340 ","End":"09:18.050","Text":"the polarity and solubility of the proteins with which they are conjugated."},{"Start":"09:18.050 ","End":"09:22.460","Text":"Meaning that whatever these carbohydrate clusters are and how many and"},{"Start":"09:22.460 ","End":"09:24.725","Text":"what complexity it affects"},{"Start":"09:24.725 ","End":"09:28.910","Text":"the polarity and the solubility of the proteins which they\u0027re conjugated,"},{"Start":"09:28.910 ","End":"09:33.800","Text":"meaning,V affecting the characteristics of these glycoproteins."},{"Start":"09:33.800 ","End":"09:38.480","Text":"Oligosaccharide chains that are attached to newly synthesized proteins in"},{"Start":"09:38.480 ","End":"09:43.400","Text":"the endoplasmic reticulum and are elaborated in the Golgi complex may also influence"},{"Start":"09:43.400 ","End":"09:47.195","Text":"the sequence of polypeptide folding events that determine"},{"Start":"09:47.195 ","End":"09:54.575","Text":"the tertiary structure of the protein."},{"Start":"09:54.575 ","End":"09:57.020","Text":"Steric interactions between peptide and"},{"Start":"09:57.020 ","End":"10:01.175","Text":"oligosaccharide may preclude 1 folding route and favor another."},{"Start":"10:01.175 ","End":"10:04.910","Text":"Steric effects or non-bonding interactions that influence the shape,"},{"Start":"10:04.910 ","End":"10:07.745","Text":"conformation and reactivity of ions and molecules."},{"Start":"10:07.745 ","End":"10:10.730","Text":"Another definition is an interaction that is caused by"},{"Start":"10:10.730 ","End":"10:13.910","Text":"the spatial arrangement of atoms in a molecule."},{"Start":"10:13.910 ","End":"10:17.840","Text":"A steric effect is basically any effect on a molecule of reaction,"},{"Start":"10:17.840 ","End":"10:21.530","Text":"etc, due to the size of atoms or groups."},{"Start":"10:21.530 ","End":"10:25.450","Text":"Common steric effects include steric hindrance and Van der Waals repulsion."},{"Start":"10:25.450 ","End":"10:27.980","Text":"When numerous negatively charged oligosaccharide chains are"},{"Start":"10:27.980 ","End":"10:31.010","Text":"clustered in a single region of a protein,"},{"Start":"10:31.010 ","End":"10:34.190","Text":"the charge repulsion among them favors the formation of"},{"Start":"10:34.190 ","End":"10:37.090","Text":"an extended rod-like structure in that region,"},{"Start":"10:37.090 ","End":"10:40.910","Text":"it doesn\u0027t allow them to fold close to each other because they repel each other."},{"Start":"10:40.910 ","End":"10:44.360","Text":"The bulkiness and negative charge of oligosaccharide chains"},{"Start":"10:44.360 ","End":"10:50.235","Text":"also protect some proteins from attack by proteolytic enzymes."},{"Start":"10:50.235 ","End":"10:53.420","Text":"Beyond these global physical effects on protein structure,"},{"Start":"10:53.420 ","End":"10:55.940","Text":"there are also more specific biological effects of"},{"Start":"10:55.940 ","End":"10:58.625","Text":"oligosaccharide chains in glycoproteins."},{"Start":"10:58.625 ","End":"11:01.610","Text":"For example, some peptide hormones that circulate in the blood have"},{"Start":"11:01.610 ","End":"11:05.629","Text":"oligosaccharide modes is that strongly influenced their circulatory half-life,"},{"Start":"11:05.629 ","End":"11:10.505","Text":"meaning how long they survive within circulation."},{"Start":"11:10.505 ","End":"11:13.010","Text":"With this, we completed the lesson on"},{"Start":"11:13.010 ","End":"11:15.650","Text":"glycoproteins within the chapter of glycoconjugates."},{"Start":"11:15.650 ","End":"11:18.095","Text":"We learned about the significance of glycoproteins."},{"Start":"11:18.095 ","End":"11:21.650","Text":"We gave examples of glycoproteins and we know a little bit the difference"},{"Start":"11:21.650 ","End":"11:26.520","Text":"between glycoproteins and proteoglycans."}],"ID":30542},{"Watched":false,"Name":"Exercise 9","Duration":"1m 38s","ChapterTopicVideoID":28993,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.020","Text":"Welcome to an exercise on glycoproteins."},{"Start":"00:04.020 ","End":"00:08.460","Text":"What are glycoproteins and how are they different from proteoglycans?"},{"Start":"00:08.460 ","End":"00:13.620","Text":"Remember they are similar conjugates in the fact that they\u0027re"},{"Start":"00:13.620 ","End":"00:20.460","Text":"both a conjugate of a sugar portion with a protein portion."},{"Start":"00:20.460 ","End":"00:25.820","Text":"The answer: glycoproteins are carbohydrate protein conjugates in which"},{"Start":"00:25.820 ","End":"00:29.390","Text":"the carbohydrate moieties are smaller and more"},{"Start":"00:29.390 ","End":"00:32.990","Text":"structurally diverse than the glycosaminoglycans,"},{"Start":"00:32.990 ","End":"00:37.010","Text":"the gags found in proteoglycans."},{"Start":"00:37.010 ","End":"00:40.130","Text":"Again, glycoproteins are"},{"Start":"00:40.130 ","End":"00:43.745","Text":"similar to proteoglycans that there are carbohydrate protein conjugates,"},{"Start":"00:43.745 ","End":"00:47.780","Text":"yet their carbohydrate moieties are smaller and"},{"Start":"00:47.780 ","End":"00:53.570","Text":"more diverse structurally than the gags in proteoglycans."},{"Start":"00:53.570 ","End":"00:57.590","Text":"Furthermore, to elaborate, the carbohydrate is attached at"},{"Start":"00:57.590 ","End":"01:00.350","Text":"its anomeric carbon through a glycosidic link to"},{"Start":"01:00.350 ","End":"01:03.425","Text":"the -OH of a serine or threonine residue,"},{"Start":"01:03.425 ","End":"01:05.030","Text":"1 of these 2 amino acids,"},{"Start":"01:05.030 ","End":"01:10.175","Text":"and that is considered an O-link because it\u0027s bound here to -OH"},{"Start":"01:10.175 ","End":"01:15.560","Text":"or through an N-glycosyl linked to the amino nitrogen of an ASN residue,"},{"Start":"01:15.560 ","End":"01:19.190","Text":"asparagine residue, and it\u0027s considered an N-linked."},{"Start":"01:19.190 ","End":"01:22.910","Text":"You will have an O-linked residue or an N-linked residue,"},{"Start":"01:22.910 ","End":"01:27.655","Text":"either to serine or threonine or to asparagine."},{"Start":"01:27.655 ","End":"01:31.535","Text":"That is a characteristic found in glycoproteins,"},{"Start":"01:31.535 ","End":"01:37.890","Text":"which is different from the proteoglycans that have gags bound to them"}],"ID":30543},{"Watched":false,"Name":"Exercise 10","Duration":"55s","ChapterTopicVideoID":28994,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.235","Text":"We have an exercise testing your knowledge on glycoproteins."},{"Start":"00:04.235 ","End":"00:07.890","Text":"Define glycophorin A and what was it given as an example for?"},{"Start":"00:07.890 ","End":"00:09.060","Text":"Glycophorin A is one of"},{"Start":"00:09.060 ","End":"00:12.972","Text":"the best characterized membrane glycoproteins of the erythrocyte membrane,"},{"Start":"00:12.972 ","End":"00:14.805","Text":"this is a type of cell."},{"Start":"00:14.805 ","End":"00:18.480","Text":"It was given as an example of an external surface of"},{"Start":"00:18.480 ","End":"00:21.930","Text":"the plasma membrane glycoproteins with arrays of"},{"Start":"00:21.930 ","End":"00:26.580","Text":"covalently attached oligosaccharides of varying complexity."},{"Start":"00:26.580 ","End":"00:30.420","Text":"It contains 60 percent carbohydrate by mass in"},{"Start":"00:30.420 ","End":"00:33.930","Text":"the form of 16 oligosaccharide chains totaling"},{"Start":"00:33.930 ","End":"00:37.970","Text":"60-70 monosaccharide residues covalently"},{"Start":"00:37.970 ","End":"00:43.270","Text":"attached to amino acid residues near the amino terminus of the polypeptide chain."},{"Start":"00:43.270 ","End":"00:50.120","Text":"15 of the oligosaccharide chains are O-linked to serine or threonine residues,"},{"Start":"00:50.120 ","End":"00:55.050","Text":"and 1 is N-linked to an asparagine residue, an ASN residue."}],"ID":30544},{"Watched":false,"Name":"Exercise 11","Duration":"3m 57s","ChapterTopicVideoID":28976,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.130","Text":"Welcome back to another exercise within the topic of glycoproteins."},{"Start":"00:05.130 ","End":"00:07.005","Text":"Which statement is false?"},{"Start":"00:07.005 ","End":"00:11.070","Text":"Let\u0027s read through all 4 statements and then let"},{"Start":"00:11.070 ","End":"00:15.615","Text":"yourself process these and see what we get."},{"Start":"00:15.615 ","End":"00:17.940","Text":"A, the same protein produced in 2 types"},{"Start":"00:17.940 ","End":"00:20.295","Text":"of tissues can result in different glycoproteins."},{"Start":"00:20.295 ","End":"00:24.720","Text":"The oligosaccharide chains represent a tissue specific marker."},{"Start":"00:24.720 ","End":"00:29.790","Text":"B, glycoproteins have multiple oligosaccharide chains."},{"Start":"00:29.790 ","End":"00:33.470","Text":"C, oligosaccharide chains that are attached to"},{"Start":"00:33.470 ","End":"00:38.265","Text":"newly synthesized proteins may influence the sequence of polypeptide folding events."},{"Start":"00:38.265 ","End":"00:41.060","Text":"D, the bulkiness and negative charge of"},{"Start":"00:41.060 ","End":"00:45.910","Text":"oligosaccharide chains protect some proteins from attack by proteolytic enzymes."},{"Start":"00:45.910 ","End":"00:49.880","Text":"Again, we\u0027re looking for something that is false, that is incorrect."},{"Start":"00:49.880 ","End":"00:54.695","Text":"The same protein produced in 2 types of tissues can result in different glycoproteins."},{"Start":"00:54.695 ","End":"00:58.775","Text":"The oligosaccharide chains represent a tissue specific marker."},{"Start":"00:58.775 ","End":"01:03.350","Text":"A is not our answer because we actually elaborated and"},{"Start":"01:03.350 ","End":"01:07.745","Text":"the same protein produced in 2 types of tissues can result in different glycoproteins."},{"Start":"01:07.745 ","End":"01:10.300","Text":"A number of cases are known in which the same protein produced in"},{"Start":"01:10.300 ","End":"01:13.220","Text":"2 types of tissues has different glycosylation patterns."},{"Start":"01:13.220 ","End":"01:17.300","Text":"For example, the human protein interferon 1 has 1 set of oligosaccharide chains when"},{"Start":"01:17.300 ","End":"01:21.490","Text":"produced in ovarian cells and a different set when produced in breast epithelial cells."},{"Start":"01:21.490 ","End":"01:24.560","Text":"The biological significance of these tissue glycoforms,"},{"Start":"01:24.560 ","End":"01:28.940","Text":"which mean any of several different forms of glycoprotein or other biological glycoside."},{"Start":"01:28.940 ","End":"01:34.085","Text":"Having different saccharides attached or having a different structure is not understood,"},{"Start":"01:34.085 ","End":"01:38.540","Text":"but in some way the oligosaccharide chains represent a tissue specific marker,"},{"Start":"01:38.540 ","End":"01:42.800","Text":"so this we know is a true statement and therefore it is not our answer."},{"Start":"01:42.800 ","End":"01:46.595","Text":"Let\u0027s move to B, glycoproteins have multiple oligosaccharide chains."},{"Start":"01:46.595 ","End":"01:48.230","Text":"What did we say about this?"},{"Start":"01:48.230 ","End":"01:50.240","Text":"We actually talked about the glycoproteins have"},{"Start":"01:50.240 ","End":"01:54.380","Text":"multiple oligosaccharide chains and the carbohydrate may constitute from"},{"Start":"01:54.380 ","End":"02:04.155","Text":"1-70 percent or more of the protein biomass."},{"Start":"02:04.155 ","End":"02:10.790","Text":"This meaning that it doesn\u0027t necessarily have multiple oligosaccharide chains,"},{"Start":"02:10.790 ","End":"02:13.545","Text":"so I will leave this to come back to it."},{"Start":"02:13.545 ","End":"02:17.180","Text":"C, oligosaccharide chains that are attached to"},{"Start":"02:17.180 ","End":"02:21.785","Text":"newly synthesized proteins may influence the sequence of polypeptide folding events."},{"Start":"02:21.785 ","End":"02:25.920","Text":"Well, we talked about this with idea of steric effect."},{"Start":"02:25.920 ","End":"02:30.620","Text":"Basically, when you have newly synthesized proteins in"},{"Start":"02:30.620 ","End":"02:32.990","Text":"the endoplasmic reticulum and elaborate and the Golgi"},{"Start":"02:32.990 ","End":"02:35.720","Text":"complex that determined the tertiary structure of the protein,"},{"Start":"02:35.720 ","End":"02:39.350","Text":"the third level structure of the protein,"},{"Start":"02:39.350 ","End":"02:44.090","Text":"the spacial arrangement steric interactions between peptide"},{"Start":"02:44.090 ","End":"02:48.950","Text":"and oligosaccharide may preclude 1 folding route and favor another."},{"Start":"02:48.950 ","End":"02:51.695","Text":"We elaborate on this in the lesson,"},{"Start":"02:51.695 ","End":"02:54.155","Text":"but basically it means the spatial arrangement."},{"Start":"02:54.155 ","End":"02:57.455","Text":"Therefore this is true and not our answer."},{"Start":"02:57.455 ","End":"03:00.635","Text":"D, the bulkiness and negative charge of oligosaccharide chains"},{"Start":"03:00.635 ","End":"03:04.565","Text":"protect some proteins from attack by proteolytic enzymes."},{"Start":"03:04.565 ","End":"03:08.090","Text":"We specifically mentioned this and use proteolytic enzymes as"},{"Start":"03:08.090 ","End":"03:12.820","Text":"an example and therefore this is a true statement and not our answers,"},{"Start":"03:12.820 ","End":"03:15.410","Text":"so what do we say about B?"},{"Start":"03:15.410 ","End":"03:19.115","Text":"This statement is not really false,"},{"Start":"03:19.115 ","End":"03:22.175","Text":"rather it is inaccurate."},{"Start":"03:22.175 ","End":"03:25.670","Text":"The correct statement would be because when we\u0027re saying glycoproteins have"},{"Start":"03:25.670 ","End":"03:29.450","Text":"multiple oligosaccharide chains, 1-70 percent."},{"Start":"03:29.450 ","End":"03:31.325","Text":"1 percent means when we have 1,"},{"Start":"03:31.325 ","End":"03:33.320","Text":"this is our correct answer,"},{"Start":"03:33.320 ","End":"03:35.285","Text":"B is the false statement."},{"Start":"03:35.285 ","End":"03:38.510","Text":"The correct statement would be if we would say,"},{"Start":"03:38.510 ","End":"03:42.440","Text":"some glycoproteins have a single oligosaccharide chain,"},{"Start":"03:42.440 ","End":"03:46.145","Text":"but many have more than 1 with the carbohydrates"},{"Start":"03:46.145 ","End":"03:51.300","Text":"constituting from 1-70 percent or more of the protein biomass,"},{"Start":"03:51.300 ","End":"03:52.425","Text":"so when you have 1 percent,"},{"Start":"03:52.425 ","End":"03:57.059","Text":"it would be that single oligosaccharide chain for example."}],"ID":30545},{"Watched":false,"Name":"Glycolipids","Duration":"8m 4s","ChapterTopicVideoID":28977,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:06.810","Text":"We\u0027re now going to the last type of glycoconjugates that we will be covering,"},{"Start":"00:06.810 ","End":"00:08.910","Text":"and that is the glycolipids."},{"Start":"00:08.910 ","End":"00:14.150","Text":"In this section, we will learn about glycolipids and their significance."},{"Start":"00:14.150 ","End":"00:18.710","Text":"Glycolipids and lipopolysaccharides are membrane components."},{"Start":"00:18.710 ","End":"00:21.710","Text":"Glycoproteins are not the only cellular components"},{"Start":"00:21.710 ","End":"00:24.230","Text":"that bear complex oligosaccharide chains."},{"Start":"00:24.230 ","End":"00:29.166","Text":"Some lipids too have covalently bound oligosaccharides,"},{"Start":"00:29.166 ","End":"00:32.705","Text":"these are glycolipids and lipopolysaccharides."},{"Start":"00:32.705 ","End":"00:38.645","Text":"Again, we have lipo from lipid, from fat,"},{"Start":"00:38.645 ","End":"00:43.090","Text":"and glyco and saccharides defining sugar,"},{"Start":"00:43.090 ","End":"00:46.940","Text":"so it is a fat and sugar conjugate."},{"Start":"00:46.940 ","End":"00:48.455","Text":"What you see here,"},{"Start":"00:48.455 ","End":"00:52.400","Text":"a figure we introduced previously with introducing glycoproteins,"},{"Start":"00:52.400 ","End":"00:55.178","Text":"which are the protein with carbohydrates attached,"},{"Start":"00:55.178 ","End":"00:57.545","Text":"you also have glycolipids,"},{"Start":"00:57.545 ","End":"00:59.750","Text":"a lipid with carbohydrate attached."},{"Start":"00:59.750 ","End":"01:03.500","Text":"You have a few of these on the membrane as well."},{"Start":"01:03.500 ","End":"01:09.820","Text":"Gangliosides are membrane lipids of eukaryotic cells in which the polar head group,"},{"Start":"01:09.820 ","End":"01:13.825","Text":"the part of the lipid that forms the outer surface of the membrane,"},{"Start":"01:13.825 ","End":"01:21.410","Text":"is a complex oligosaccharide containing sialic acid and other monosaccharide residues."},{"Start":"01:21.980 ","End":"01:24.610","Text":"If you remember generally,"},{"Start":"01:24.610 ","End":"01:26.875","Text":"a phospholipid that creates"},{"Start":"01:26.875 ","End":"01:33.190","Text":"the membrane lipid bi-layer has this head and this is the polar head group."},{"Start":"01:33.190 ","End":"01:39.230","Text":"Now, some of the oligosaccharide moieties of gangliosides,"},{"Start":"01:39.230 ","End":"01:41.825","Text":"such as those that determine human blood groups,"},{"Start":"01:41.825 ","End":"01:45.725","Text":"are identical with those found in certain glycoproteins,"},{"Start":"01:45.725 ","End":"01:50.820","Text":"which therefore also contribute to blood group type determination."},{"Start":"01:52.790 ","End":"01:57.725","Text":"Like the oligosaccharide moieties of glycoproteins,"},{"Start":"01:57.725 ","End":"02:01.204","Text":"those of membrane lipids are generally possibly"},{"Start":"02:01.204 ","End":"02:05.210","Text":"always found on the outer face of the plasma membrane."},{"Start":"02:05.210 ","End":"02:12.050","Text":"In this figure, we see the polar head group of the membrane lipids."},{"Start":"02:12.050 ","End":"02:15.125","Text":"Gangliosides are in the eukaryotic cell,"},{"Start":"02:15.125 ","End":"02:19.560","Text":"and you have these"},{"Start":"02:19.780 ","End":"02:26.890","Text":"multiple and the ones opposing them where you have the hydrophobic side,"},{"Start":"02:26.890 ","End":"02:29.620","Text":"the fatty chains interacting with each other and creating"},{"Start":"02:29.620 ","End":"02:33.325","Text":"the central portion with the polar heads on the outside,"},{"Start":"02:33.325 ","End":"02:38.245","Text":"and you have these containing"},{"Start":"02:38.245 ","End":"02:44.800","Text":"a complex oligosaccharide with a sialic acid and other monosaccharide residues,"},{"Start":"02:44.800 ","End":"02:47.680","Text":"and these are your glycolipids of"},{"Start":"02:47.680 ","End":"02:50.710","Text":"the plasma membrane found on"},{"Start":"02:50.710 ","End":"02:54.430","Text":"the external side because this is the internal side of the cell."},{"Start":"02:54.430 ","End":"02:56.335","Text":"This is the inside of the cell."},{"Start":"02:56.335 ","End":"03:01.044","Text":"This outside here is the extracellular portion."},{"Start":"03:01.044 ","End":"03:05.885","Text":"Lipopolysaccharides are the dominant surface feature"},{"Start":"03:05.885 ","End":"03:10.325","Text":"of the outer membrane of gram-negative bacteria,"},{"Start":"03:10.325 ","End":"03:11.765","Text":"such as E. Coli,"},{"Start":"03:11.765 ","End":"03:16.600","Text":"Escherichia coli, and Salmonella typhimurium."},{"Start":"03:16.600 ","End":"03:23.825","Text":"We see here is a gram-negative bacteria with lipopolysaccharides."},{"Start":"03:23.825 ","End":"03:25.160","Text":"That\u0027s the other type."},{"Start":"03:25.160 ","End":"03:29.675","Text":"Glycolipids can be found in eukaryotes."},{"Start":"03:29.675 ","End":"03:39.240","Text":"Lipopolysaccharides are in the prokaryotic bacteria with a gram-negative membrane."},{"Start":"03:39.240 ","End":"03:42.050","Text":"You see here the lipopolysaccharides."},{"Start":"03:42.050 ","End":"03:44.570","Text":"Here\u0027s another way, the lipopolysaccharide."},{"Start":"03:44.570 ","End":"03:50.360","Text":"This illustrates in more detail the structure of the lipopolysaccharide."},{"Start":"03:50.360 ","End":"03:52.430","Text":"These molecules are prime targets of"},{"Start":"03:52.430 ","End":"03:56.540","Text":"the antibodies produced by the vertebrate immune system in response"},{"Start":"03:56.540 ","End":"03:58.520","Text":"to bacterial infection and are"},{"Start":"03:58.520 ","End":"04:02.210","Text":"therefore important determinants of the serotype of bacterial strains."},{"Start":"04:02.210 ","End":"04:08.840","Text":"Serotypes refers to strains that are distinguished on the basis of antigenic properties."},{"Start":"04:08.840 ","End":"04:13.270","Text":"The lipopolysaccharide of salmonella"},{"Start":"04:13.270 ","End":"04:19.110","Text":"contains 6 fatty acids bound to 2 glucosamine residues,"},{"Start":"04:19.110 ","End":"04:23.920","Text":"1 of which is the point of attachment for a complex oligosaccharide."},{"Start":"04:23.920 ","End":"04:31.680","Text":"What you see here is that there is 6 fatty acids."},{"Start":"04:31.680 ","End":"04:33.405","Text":"You have 1, 2,"},{"Start":"04:33.405 ","End":"04:35.640","Text":"3, 4, 5,"},{"Start":"04:35.640 ","End":"04:40.890","Text":"6 bound to 2 glucosamine residues, 1,"},{"Start":"04:40.890 ","End":"04:50.900","Text":"2, in the lipopolysaccharide of the example of salmonella bacteria,"},{"Start":"04:50.900 ","End":"04:57.750","Text":"the gram-negative bacteria, Salmonella typhimurium."},{"Start":"04:57.750 ","End":"05:01.505","Text":"E. Coli has similar but unique lipopolysaccharides."},{"Start":"05:01.505 ","End":"05:03.380","Text":"When you look here, again,"},{"Start":"05:03.380 ","End":"05:08.105","Text":"another illustration with a gram-negative bacteria with a cell wall structure and LPS."},{"Start":"05:08.105 ","End":"05:11.750","Text":"LPS is lipopolysaccharide. Again,"},{"Start":"05:11.750 ","End":"05:15.855","Text":"you see you have the 6 fatty acid chains,"},{"Start":"05:15.855 ","End":"05:19.470","Text":"you have the 2 glucosamine residues,"},{"Start":"05:19.470 ","End":"05:21.725","Text":"and you see here how it is."},{"Start":"05:21.725 ","End":"05:27.290","Text":"It\u0027s basically membrane peptidoglycan,"},{"Start":"05:27.290 ","End":"05:28.460","Text":"and on the outside,"},{"Start":"05:28.460 ","End":"05:30.770","Text":"you have the lipopolysaccharides."},{"Start":"05:30.770 ","End":"05:32.890","Text":"You have here the description."},{"Start":"05:32.890 ","End":"05:36.880","Text":"The legend will go into this a little later."},{"Start":"05:36.880 ","End":"05:43.920","Text":"Now the lipopolysaccharides of some bacteria are toxic to humans and other animals."},{"Start":"05:43.920 ","End":"05:45.370","Text":"For example, they\u0027re responsible for"},{"Start":"05:45.370 ","End":"05:47.680","Text":"the dangerously lowered blood pressure that occurs in"},{"Start":"05:47.680 ","End":"05:52.255","Text":"toxic shock syndrome resulting from gram-negative bacterial infections."},{"Start":"05:52.255 ","End":"05:55.120","Text":"Now, looking at the structure again,"},{"Start":"05:55.120 ","End":"05:58.000","Text":"we have the 6 fatty acids here,"},{"Start":"05:58.000 ","End":"06:04.675","Text":"we have phosphates that are bound to the 2 glucosamine residues."},{"Start":"06:04.675 ","End":"06:06.660","Text":"This is lipid A."},{"Start":"06:06.660 ","End":"06:11.170","Text":"This is what it\u0027s referred to as part of the LPS, the lipopolysaccharide structure,"},{"Start":"06:11.170 ","End":"06:14.784","Text":"lipid A, and then you have the sugars,"},{"Start":"06:14.784 ","End":"06:16.255","Text":"and that is down here."},{"Start":"06:16.255 ","End":"06:19.870","Text":"You have the O-specific polysaccharide, O-antigen,"},{"Start":"06:19.870 ","End":"06:22.550","Text":"and then here you have the outer core,"},{"Start":"06:22.550 ","End":"06:25.730","Text":"and this is the core polysaccharide."},{"Start":"06:25.730 ","End":"06:27.440","Text":"What you have here,"},{"Start":"06:27.440 ","End":"06:30.875","Text":"this is the inner core of the polysaccharide,"},{"Start":"06:30.875 ","End":"06:34.385","Text":"this is the outer core of the polysaccharide,"},{"Start":"06:34.385 ","End":"06:37.040","Text":"and then you have the O-specific polysaccharide,"},{"Start":"06:37.040 ","End":"06:38.945","Text":"O-antigen, given as an example."},{"Start":"06:38.945 ","End":"06:43.580","Text":"This is basically the saccharide,"},{"Start":"06:43.580 ","End":"06:47.000","Text":"the sugar portion of the LPS."},{"Start":"06:47.000 ","End":"06:52.940","Text":"So this is the saccharide and this is the lipid portion."},{"Start":"06:52.940 ","End":"06:55.220","Text":"If you look at the other figures, it\u0027s the same idea."},{"Start":"06:55.220 ","End":"06:58.070","Text":"You have the O-specific polysaccharide, O-antigen,"},{"Start":"06:58.070 ","End":"07:02.450","Text":"you have the core polysaccharide with the inner core,"},{"Start":"07:02.450 ","End":"07:03.620","Text":"the outer core,"},{"Start":"07:03.620 ","End":"07:05.315","Text":"and then you have the lipid A,"},{"Start":"07:05.315 ","End":"07:07.940","Text":"that is the 6 fatty chains,"},{"Start":"07:07.940 ","End":"07:12.460","Text":"fatty acids bound to the 2 glucosamine residues."},{"Start":"07:12.460 ","End":"07:15.385","Text":"Here\u0027s your legend. Here\u0027s your legend."},{"Start":"07:15.385 ","End":"07:18.725","Text":"These are all depicting the same idea."},{"Start":"07:18.725 ","End":"07:22.010","Text":"To summarize, we can say in essence"},{"Start":"07:22.010 ","End":"07:25.190","Text":"that glycolipids and lipopolysaccharides are components of"},{"Start":"07:25.190 ","End":"07:26.330","Text":"the plasma membrane with"},{"Start":"07:26.330 ","End":"07:32.360","Text":"covalently attached oligosaccharide chains exposed on a cell\u0027s outer surface."},{"Start":"07:32.360 ","End":"07:34.955","Text":"You have the glycolipid."},{"Start":"07:34.955 ","End":"07:44.280","Text":"This is in the eukaryotic membrane on the external portion of the plasma membrane,"},{"Start":"07:44.280 ","End":"07:47.735","Text":"and then you have the lipopolysaccharides."},{"Start":"07:47.735 ","End":"07:50.660","Text":"These are found in gram-negative bacteria,"},{"Start":"07:50.660 ","End":"07:52.670","Text":"a type of prokaryotic cell,"},{"Start":"07:52.670 ","End":"07:56.555","Text":"again, a component of the plasma membrane,"},{"Start":"07:56.555 ","End":"07:59.990","Text":"the outer membrane of the gram-negative bacteria,"},{"Start":"07:59.990 ","End":"08:05.750","Text":"and these are covalently attached oligosaccharide chains exposed on"},{"Start":"08:05.750 ","End":"08:12.865","Text":"the cell outer surface with the lipid being what\u0027s embedded in the actual membrane."},{"Start":"08:12.865 ","End":"08:16.040","Text":"With that, we completed the lesson on glycolipids"},{"Start":"08:16.040 ","End":"08:20.340","Text":"and we learned about glycolipids and their significance."}],"ID":30546},{"Watched":false,"Name":"Exercise 12","Duration":"3m 31s","ChapterTopicVideoID":28978,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.140 ","End":"00:04.510","Text":"Welcome to an exercise covering glycolipids."},{"Start":"00:04.510 ","End":"00:07.340","Text":"Part 1, which statement is false?"},{"Start":"00:07.340 ","End":"00:11.920","Text":"A. Glycolipids and lipopolysaccharides are cell membrane components."},{"Start":"00:11.920 ","End":"00:20.900","Text":"B. Like the oligosaccharide moieties of glycoproteins,"},{"Start":"00:20.900 ","End":"00:24.545","Text":"those of membrane lipids are found on the outer face of the plasma membrane."},{"Start":"00:24.545 ","End":"00:28.220","Text":"C. Lipopolysaccharides are the dominant surface feature"},{"Start":"00:28.220 ","End":"00:31.360","Text":"of the outer membrane of gram-negative bacteria."},{"Start":"00:31.360 ","End":"00:34.970","Text":"D. These molecules are prime targets of antibodies and are"},{"Start":"00:34.970 ","End":"00:39.275","Text":"therefore important determinant of the serotype of bacterial strains."},{"Start":"00:39.275 ","End":"00:46.699","Text":"E. Lipopolysaccharides of bacteria are toxic to humans and other animals."},{"Start":"00:46.699 ","End":"00:51.095","Text":"I\u0027ll go through this one-by-one and talk about it."},{"Start":"00:51.095 ","End":"00:54.875","Text":"Glycolipids and lipopolysaccharides are cell membrane components."},{"Start":"00:54.875 ","End":"00:57.590","Text":"That is the basis for this entire lesson,"},{"Start":"00:57.590 ","End":"00:58.940","Text":"so this is a true statement,"},{"Start":"00:58.940 ","End":"01:00.545","Text":"therefore, it is not our answer."},{"Start":"01:00.545 ","End":"01:04.710","Text":"B. Like the oligosaccharide moieties and glycoproteins,"},{"Start":"01:04.710 ","End":"01:08.780","Text":"those a membrane lipids are found on the outer face of the plasma membrane."},{"Start":"01:08.780 ","End":"01:14.180","Text":"We mentioned that the oligosaccharide moieties or the glycolipids are generally and"},{"Start":"01:14.180 ","End":"01:19.040","Text":"possibly always found on the outer face of the plasma membrane."},{"Start":"01:19.040 ","End":"01:22.865","Text":"Therefore, this is a true statement and not our answer."},{"Start":"01:22.865 ","End":"01:25.655","Text":"Now in the case of glycolipids,"},{"Start":"01:25.655 ","End":"01:28.250","Text":"the lipid is usually embedded in the membrane,"},{"Start":"01:28.250 ","End":"01:32.645","Text":"whereas in the glycoprotein the protein itself is also bound to the membrane,"},{"Start":"01:32.645 ","End":"01:37.745","Text":"but not necessarily embedded where the lipid can be part of the membrane itself."},{"Start":"01:37.745 ","End":"01:42.600","Text":"Now, C. Lipopolysaccharide, LPS,"},{"Start":"01:42.600 ","End":"01:47.690","Text":"are the dominant surface feature of the outer membrane of gram-negative bacteria,"},{"Start":"01:47.690 ","End":"01:50.765","Text":"such as E-coli and salmonella."},{"Start":"01:50.765 ","End":"01:56.830","Text":"Well, this again is true and therefore not our answer."},{"Start":"01:56.830 ","End":"02:00.470","Text":"D. These molecules are prime targets of antibodies and"},{"Start":"02:00.470 ","End":"02:05.525","Text":"therefore important determinants of the serotype of bacterial strains."},{"Start":"02:05.525 ","End":"02:11.870","Text":"Well, we did mention that antibodies recognize these and therefore"},{"Start":"02:11.870 ","End":"02:17.285","Text":"these specific LPS structures"},{"Start":"02:17.285 ","End":"02:23.975","Text":"allow us to identify the bacteria and we defined what the word serotype mean,"},{"Start":"02:23.975 ","End":"02:26.300","Text":"meaning that these are strains that are"},{"Start":"02:26.300 ","End":"02:29.480","Text":"distinguished on the basis of antigenic properties."},{"Start":"02:29.480 ","End":"02:32.450","Text":"These molecules are prime targets"},{"Start":"02:32.450 ","End":"02:35.180","Text":"of the antibodies produced by the vertebrate immune system in"},{"Start":"02:35.180 ","End":"02:37.070","Text":"response to bacterial infection and are"},{"Start":"02:37.070 ","End":"02:41.345","Text":"therefore important determinants of the serotype of bacterial strains."},{"Start":"02:41.345 ","End":"02:43.520","Text":"True statement, not our answer."},{"Start":"02:43.520 ","End":"02:49.235","Text":"E. Lipopolysaccharides of bacteria are toxic to humans and other animals."},{"Start":"02:49.235 ","End":"02:52.295","Text":"Well, this isn\u0027t necessarily true."},{"Start":"02:52.295 ","End":"02:54.440","Text":"They can be toxic,"},{"Start":"02:54.440 ","End":"02:59.030","Text":"but they aren\u0027t by definition toxic to humans and other animals,"},{"Start":"02:59.030 ","End":"03:00.875","Text":"therefore, this is false."},{"Start":"03:00.875 ","End":"03:05.760","Text":"This is an inaccurate statement and therefore our correct answer."},{"Start":"03:05.760 ","End":"03:09.094","Text":"Part 2, correct the false statement."},{"Start":"03:09.094 ","End":"03:12.755","Text":"Considering E is our false statement to correct it,"},{"Start":"03:12.755 ","End":"03:15.080","Text":"we can say the lipopolysaccharides of"},{"Start":"03:15.080 ","End":"03:19.490","Text":"some bacteria are toxic to humans and other animals."},{"Start":"03:19.490 ","End":"03:21.290","Text":"For example, they\u0027re responsible for"},{"Start":"03:21.290 ","End":"03:23.450","Text":"the dangerously lowered blood pressure that occurs in"},{"Start":"03:23.450 ","End":"03:28.160","Text":"toxic shock syndrome resulting from gram-negative bacterial infections."},{"Start":"03:28.160 ","End":"03:32.490","Text":"With that, we completed this exercise."}],"ID":30547},{"Watched":false,"Name":"Exercise 13","Duration":"48s","ChapterTopicVideoID":28979,"CourseChapterTopicPlaylistID":293021,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.700","Text":"Welcome back to another exercise on the lesson covering glycolipids."},{"Start":"00:05.700 ","End":"00:07.950","Text":"What are gangliosides?"},{"Start":"00:07.950 ","End":"00:12.870","Text":"Gangliosides are membrane lipids of eukaryotic cells in which the polar head group,"},{"Start":"00:12.870 ","End":"00:15.510","Text":"the part of the lipid that forms the outer surface of the membrane,"},{"Start":"00:15.510 ","End":"00:18.480","Text":"the round shape is a complex oligosaccharide"},{"Start":"00:18.480 ","End":"00:22.335","Text":"containing sialic acid and other monosaccharide residues."},{"Start":"00:22.335 ","End":"00:25.440","Text":"Some of the illegal saccharide moieties of gangliosides,"},{"Start":"00:25.440 ","End":"00:27.825","Text":"such as those that determine human blood groups,"},{"Start":"00:27.825 ","End":"00:31.680","Text":"are identical with those found in certain glycoproteins,"},{"Start":"00:31.680 ","End":"00:35.500","Text":"which therefore also contribute to blood group type determination."},{"Start":"00:35.500 ","End":"00:38.885","Text":"Like the oligosaccharide moieties of glycoproteins,"},{"Start":"00:38.885 ","End":"00:42.364","Text":"those of membrane lipids are generally possibly"},{"Start":"00:42.364 ","End":"00:47.070","Text":"always found on the outer face of the plasma membrane."}],"ID":30548}],"Thumbnail":null,"ID":293021}]

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