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Video in TIB AV-Portal: Polysaccharides

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This is the third (and final) quarter of the organic chemistry series. Topics covered include: Fundamental concepts relating to carbon compounds with emphasis on structural theory and the nature of chemical bonding, stereochemistry, reaction mechanisms, and spectroscopic, physical, and chemical properties of the principal classes of carbon compounds. This video is part of a 27-lecture undergraduate-level course titled "Organic Chemistry" taught at UC Irvine by Professor Susan King. Index of Topics: 00:20 - Reduction Reactions of Sugars 02:55 - Disaccharides 10:03 - Cellulose 12:14 - Starches 16:25 - Sweeteners, Fats, and Drugs Derived from Sugars 29:46 - Amino Sugars 30:36 - N Glycosides
Glucose Fructose Chain (unit) Carbohydrate Chemical reaction Alcohol Zigarettenschachtel Computer animation Redox Pemoline Disaccharide Sugar Thermoforming Biochemistry
Glucose Chain (unit) Digestate Chemical property Carbohydrate Oligosaccharide Polysaccharide Süßstoff Cholesterol Alpha particle Saccharose Molecule Cellulose Enzyme Colourant Lipide Helix Sugar Solubility Biochemistry Lysergic acid diethylamide Zahnpasta River source Alcohol Branch (computer science) Polymer Cobaltoxide Isotopenmarkierung Ionenbindung Gum arabic Stereochemistry Glykogen Ice sheet Hydroxyl Cross-link Deterrence (legal) Diet food Starch Redox Beta sheet Active site Setzen <Verfahrenstechnik> Fructose Hydrogen bond Carbon (fiber) Biodiesel Glykoside Water Mannitol Gesundheitsstörung Recreational drug use Drop (liquid) Computer animation Functional group Zuckeralkohole
Glucose Semiotics Chain (unit) Insulin Amine Süßstoff Chlorine Saccharose Molecule Cyanohydrine Sugar Cell membrane Xylose Calcium Galantamine Lysergic acid diethylamide Omega-6-Fettsäuren Walking Chemical reaction Cancer Wine tasting descriptors Electronic cigarette Artificial leather Azo coupling Chemical compound Polymer Home remedy Cobaltoxide Stuffing Isotopenmarkierung Gum arabic Biosynthesis Candy Chocolate Deoxyribose Ester Xylitol Reaction mechanism Sprayer Ribose Hydroxyl Food Diet food Potato chip Sweetness Cell (biology) Tube (container) Redox Cryogenics Storage tank Sea level Mixture Pain Process (computing) River mouth Fructose Setzen <Verfahrenstechnik> Stickstoffatom Glucosamin Ketone Carbon (fiber) Aldehyde Baking Blausäure Glykoside Mannitol Recreational drug use Computer animation Functional group Zuckeralkohole Disaccharide
Computer animation
good afternoon we're going to get started this our last let your last lecture evoke M bittersweet moment right all right so
we are going to finish up the carbohydrates chapter and then I will have a discussion after this and then I will have office hours from two to three extra office hours and then I will see you at the review tonight okay any questions before we get started any questions about the final nobody huh yes there will be terminology for carbohydrates but not any IU Pack nomenclature okay any other questions yes he asked if we have to memorize the open chain forms of the only sugar that you have to memorize is that glucose and fructose I'll put the top really loud can you guys quiet down so I can hear her ah doggone it off to email you about that once I write the test don't you know you about that okay any other questions over here yes what the review is from 6 to 8 in HS LH right FiOS I lecture hall ok anything else HS LH used to be called BIOS I lecture hall now it's h SL h alright so we were left off last time almost finishing talking about reactions of sugars and so III ended with reduction and so this is an alder tall and you can see the Oh L is for alcohol so that's an alder tall and we also talked about the fact that when you reduce that sugar you turn it into something that's a chiral so even though it has three planes of symmetry I mean three stereo centers it has this cleanup Cemetery so it is actually a chiral alright let's talk about disaccharides all right so we were talking about the
different types of linkages one for Prime one six Prime and one one Prime and you need to be able to know how to label those linkages all right and so we were tall so talking about reducing sugars and non reducing sugars so let's label these as reducing sugars we have as long as we have one anomeric carbon as a hemiacetal then it is a reducing sugar so this is a hemiacetal so that's a reducing sugar that's a hemiacetal so that's also a reducing sugar so if you oxidize this you'll oxidize right here this will still stay intact okay so you're gonna oxidize right here you're gonna oxidize right here this ring will still stay intact all right so this is a reducing sugar and this is also a reducing sugar all right so we've also talked about the fact that what did we label this one for prime glucose itta clink egde here's gentie bios it's a beta one six prime glucose itta klinken two glucose units and so we have sugar number one this is glucose and this is also glucose the one six prime linkages rare and disaccharides it's usually common as branch points and polysaccharides so if you have a long saccharide chain then the one six prime is the branches cross linking between the two chains but here is an example of a real beta one six Prime in a in a disaccharide and so we do recognize this as glucose you recognize this is glucose so this right here is beta because that oh that oh our group is equatorial so it's beta and it is bonded through carbon one this is one two three four five six carbon one of sugar one and it's bonded through on let's let's label those in it let's knit number those in a different color through carbon number six of the second sugar one two three four five did I skip one one two three four five six no here we go through carbon number six bonded through carbon six whoops carbon six of the second sugar so therefore a beta one six prime and the glucose it ik is specific for sugar number one being glucose sucrose on the other hand is it's it's sometimes called a1 one time it's also called it's actually a one two prime and so you recognize we were going to call this is so this is of course this table sugar sugar number one is glucose notice it is this hydroxyl on glucose this o are is is alpha and it is so this is an alpha glycosidic linkage on glucose so we can call it an alpha let me just erase that alpha glucose itta clink egde on glucose notice in sucrose is unusual because it's the anomeric carbon of sugar 1 and the anomeric carbon of sugar 2 are actually the ones that are bonded together alright so this on the other hand is beta this is a beta linkage at carbon number 2 and so because we have the an americorps bit of both sugars it's a11 prime but it's actually a 1 2 prime because if you number on fructose let's number both of them this is 1 2 3 4 5 6 if you number fructose we start right here 1 2 3 4 5 6 so we're actually bonded through carbon number 2 through the oxygen on carbon 2 so if I have any kind of linkage like this on the test I would accept either a 1 1 prime or a 1 2 prime can call I either name it is this say is this a reducing sugar I'm seeing some head shaking no this is a non reducing sugar and that's because there are no hemiacetals in this in this molecule both of the anomeric carbons are bonded together yes a glycosidic is is is generic and and more specific is where you use the name for the sugar number one specific would be glucose it ik so it's a glycosidic bond so that's the generic name so when the test I'll say be as specific as possible and so you rather than writing glycosidic you would write glucose it ik or sugar number one okay questions on that anybody all right so we're not going to talk about oligosaccharides but we are going to jump right to polysaccharides and so here's cellulose a polymer of d-glucose with the beta 1-4 prime linkage you recognize that right away right so here's let's number here one two three four five six one two three four five six - what we're looking for is we're bonded through carbon number four carbon four of second sugar and
this is beta so the and and since each each of some mutant is glucose then this is a beta 1-4 prime glucose itta clink ??j-- all right and we don't have we don't have the capability of digesting cellulose humans and other mammals can't digest cellulose because we don't have the beta-glucosidase enzyme that you need to do this it's very difficult to digest so beta-glucosidase is synthesized only by bacteria so it's just like digestive bacteria of ruminants and termites so like cows when cows eat hay they have bacteria in their stomach that make this enzyme so they can break apart the cellulose bonding even so it's even still very hard for them because don't they don't they regurgitate and then swallow back again and then regurgitate and swallow back again yeah so and then even then they're only digesting about 30 30 percent of it and that's why cow droppings look like you know grass because that's all the undigested grass in there so it's really hard to digest we on the other hand are designed to digest not the beta 1-4 prime but the bathe the alpha 1-4 prime so all of the searches glycogen amylose all of the starches are alpha so where's notice we're bonded through carbon number four of the second sugar and this is alpha each one of these units is glucose so this is an alpha 1-4 prime glucose itta clink ??j-- alright and here's an example so this is this is amylose right here and this is amylopectin another sugar and so all of these bonds right here are all the ones 1 4 prime alpha 1 4 prime Glueck acidic linkages and here's what I was talking about right here so we have a long polymer chain of 1 4 prime Fluke acidic linkages and now we have one of these 1 6 prime that are that are cross linking these two polymer chains so this right here is an alpha 1 6 prime glucose itta clink ??j-- and this is called a branch point so so seriously the only difference between if we scroll back up and I will scroll back down again the only difference between cellulose which we can't digest and starts which we can digest is that we don't have the enzyme necessary to do the beta 1-4 pine linkage and completely different physical properties just because of the stereochemistry of that one carbon so because of this because if you look at the way I've drawn cellulose it actually makes long sheets like this and then there's hydrogen bonding between the sheets in starch it's not long sheets because of this settle stereochemical distance we actually this actually kinks the molecule into an alpha helix and so you have all these hydroxyls on the outside which interact with the environment so you get a lot of hydrogen bonding and so these are all water-soluble cellulose of course is not water-soluble that's why when it rains our trees don't dissolve our grass doesn't dissolve okay so they don't hydrogen bond but the starches do so pretty trippy when you think about that that's just the stereochemistry at one at one site in the molecule so so this is alpha linkage kinks the polymer chain into an alpha helix therefore we have increased hydrogen bonding therefore its soluble in water cellulose is not so most of the hydrogen bonding and cellulose is happening between its own molecules and not with the water in the environment and so glycogen is similar to amylopectin but has more of these 1/6 prime cross-links questions on polysaccharides anybody yeah we have 3 more pages left no four more pages it's awesome ok so I want to move on to talk about some other things with sugars sweeteners fats drugs derived from sugars so I don't know if you're aware that you know the latest research is coming out about cholesterol and heart disease and fat is not the M an enemy that it was painted out to be actually sugar is the enemy sugar is the reason why yeah we Lal love sugar but sugar is the problem not fats and that's why while we have while we have cut down on fat we have increased our sugar intake and people have gotten heavier and more heart disease okay so there's a lot of interest in artificial sweeteners we like things sweet I mean that were naturally made that way so why don't we have some artificial sweeteners that we can use that aren't going to have this effect and so here's some some common artificial sweeteners that you probably have run across these guys here D glues the tall the mannitol diesel at all Z Multi tall D multi tall these are sugar alcohols if you've ever gone on an Atkins diet the Atkins diet where you're not supposed to have any carbohydrates or very low carbohydrates you're familiar with these alcohols this is actually sorbitol so if you look on labels you'll see this in a lot of gums toothpaste things like that they don't want it they want your toothpaste to taste good but they don't want to put sugar in it right because it's just going to feed the bacteria that eat your gums away I mean your teeth away so they add sorbitol cuz it's sweet this is made from reduction
of what with sugar yes it's made from reduction of glucose then there's de mannitol on this is reduction from from reduction of nanos and then d xylitol actually is a really good one because it it prevents bacteria from sticking to mucous membranes and adhering to cells and the gum nasal passages and all of this kind of stuff so this is made from rejection of xylose so it prevents bacteria from adhering to cells in the nose mouth gums etc so if you chew a gum that's made with xylitol it's actually going to cut down on the number of cavities that you have hearing tube bacteria and gum nasal passages so they used to also use this in nasal spray to nasal passages and mouth I guess that would be your gums right it also aids in rima know it binds to calcium and AIDS in reminyl men remineralizing your teeth so it's got a lot of good qualities and then there's maltitol again if you've ever been on an Atkins diet and you have these sugar-free candies or sugar-free chocolates and things like that and and what they warn you on the label is don't eat too much or it will cause severe gastric disturbances and they really do mean that they really really do mean that my sister when I was a teenager my sister ate a whole bag of sugar free candy and her stomach was out to here like this honestly it was just she was look like she was seven months pregnant and she was in a lot of pain so you really they really do mean that so maltitol also a sugar alcohol all of the sugar alcohols are difficult to digest so it's okay if you have some in some gum that's not very much but if you're eating a food that is significantly sweetened with these it causes a lot of gastrointestinal distress we'll say difficult to digest excess causes well we'll just bull just kind of likes a severe gastrointestinal that sounds I can't even spell today intestinal issues we'll just say issues rather than getting specific so and then this is this is sucralose Splenda also an artificial sweetener it actually has zero calories and it's made from sucrose so it goes through I'm like a three or four step process and during that process this Oh H on fructose gets converted to a chlorine this gets converted to a chlorine and this gets converted to a chlorine but it also appears so during synthesis because remember this is from this is from sucrose so that had that hydroxyl that this chlorines replacing should be equatorial and it's not so during synthesis c4 on glucose memorizes so we change to the other epimer alright and then there's some newer things TD tagatose is actually they're trying to build a market for D tagatose as an as a natural naturally occurring sweetener so this is naturally occurring it is 92% as sweet as sucrose but it only has 38 percent of the calories it has a localized low gloat low glycemic index so it doesn't have really any effect on insulin levels very little effect on insulin levels blood sugar and the problem is that it when you when you bake with it it turns things black so your baked goods problem turns baked goods black so you can't really bake with it so it Browns too quickly the holy grail for people who would like to make a lot of money on artificial sweeteners is El glucose if you could make El glucose economically it tastes exactly like glucose tastes just like sugar it bakes just like sugar but it is not digested by the body so you could have everything that you eat right now if you could come up with a inexpensive synthesis of El glucose I think people would be even really willing to pay lots of money for it because it tastes exactly real so maybe somebody out here is going to come up with a synthesis of El glucose and we can use that the problem is is that with all these artificial sweeteners is whenever you're ingesting large amounts of something that's not digested it causes problems with your intestines okay so the so digestive issues and the other thing they're finding is that that these are artificial sweets and sweeteners are alter the brains taste and response signaling signaling so people luta who do these all the time they crave more sugar number one nor real sugar but after a while they lose the ability to just distinguish between something that's artificially sweetened and really sweetened so it's like you you have something that's artificially sweetened and your body says I want more of that because I'm not really getting the sugar that I'm thinking I'm getting from that it kind of messes with that signaling so really the bottom line is you really need to eat less sugar you know lose our sweet tooth all right so this is olestra key can you can you dig out the sugar that's buried in this molecule what is that it's also made from sucrose and what they've done very clever they they put long long acid chains so basically this is fake fat thick is not digestible
it's it's completely fake fat um these are long chains so these are fatty acids but the body doesn't have the ability to hydrolyze these esters so they stay on and they get passed right through the body I don't even know if this is still around anymore they used it and there was light lays do they still sell light lays I don't know again lots of problems when you ingest food that's not to be digested so gastrointestinal problems if you eat too many you know of these Lay's chips and everything that the sad thing is is they they put like thirty thirty years and two billion dollars to develop and I don't think it really has taken off and two billion dollars and of course the sad news is now that's not the culprit sugar is so that was like a wasted you know effort right so again it's fake fat two hundred to be digested all right and this is so that's olestra this is a disaccharide found in the seats of food such as cherries peaches and apricots when it's carefully hydrolyzed at low temperature the product is oxidized you get this compound late role which was very big in the 70s as an alternative cancer treatment and what happens is if you notice right here if you hydrolyze this and it is hydrolyzed when it goes into your body if you hydrolyze it's a glycoside and if you hydrolyze the glycoside you get glucose plus and hopefully you'll recognize the functional group on this molecule right here well would that functional group you called it's a cyanohydrin right is that a reversible reaction forming a cyanohydrin yes it undergoes and it will draw it down here because I didn't leave myself enough room it undergoes reverse cyanohydrin formation in the body to yield an aldehyde and HCN hydrogen cyanide and this is actually catalyzed by beta-glucosidase so catalyzed beta-glucosidase and so a lot of people a lot of people died from taking late roll and so it was like everybody it was kind of one of these things where it was sort of painted as this is the miracle drugs your doctor doesn't want you to know about because they want to use their own drugs that they're making money on and they don't want you to get well because then they won't have any patients you really need to try it so people would go down to Mexico to take the late roll and they would end up dying so because it's cyanide you're giving yourself cyanide anyway just thought you'd like that story so a couple more different sugar types and we're going to finish early today all right so what does this molecule look like it's glucose but one of the this hydroxyl right here has been changed to an amine so this is d cloody on glucosamine popular natural remedy for arthritis it's mixed with chondroitin to treat osteoarthritis so it's very popular thing that you could buy in a lot of stores it's not really super proven to be effective but a lot of people feel it is and they still buy it so that's that's a good example of that and then there's n glycosides which are like glycosides except instead of an oxygen here you'd have a nitrogen so here's an example right here we'll draw this here and we'll get a little practice drawing chairs I'm drawing a squiggly line of because of course I have a mixture of an immerse and the mechanism for this is going to look just like the mechanism for when we formed a glycoside earlier in this chapter okay so the same exact thing we have a little bit of acid catalyst that means going to we're going to kick off this hydroxyl and then the means going to attack and so you can also find this mechanism is the same as formation of a carbon carbon ol amine which is similar to a hemiacetal and that from a ketone or an aldehyde which we learned in on page 46 of the notes all right so that's an end glycoside again related to a glycoside and the only difference here is that we have a nitrogen rather than an oxygen there and so there's two end glycosides of two sugars d-ribose two deoxyribose are particularly note noteworthy so here's D ribose and here's two deoxyribose so we're missing the hydroxyl here and when we make it end glycoside of these we get cited e and two deoxyadenosine pretty awesome you learned about that already right didn't know there were certain glycosides did you and it probably wouldn't have been able to draw a mechanism for those for that formation but now you could write all right we're gonna stop right there if you guys have test questions or any
questions you can come on up thank you thank you