Polysaccharides - Video Tutorials & Practice Problems
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concept
Polysaccharides Concept 1
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Now, polysac rides also called glycans. They can be enormous with over 1 million units while at the same time, their composition can stay relatively simple. Now, we're gonna say they usually consist of one or two mono sac rides that are repetitively linked together. Now, their functions come in two types. We have those polysaccharides that are basically structural support. So those were mark green and then we have those that act as energy storage, those who mark in red. If we take a look at our chart here, we have our most common polysaccharides. The sources where they come from, are they from animals? Are they from plants? Are they from something other? We talk about the different types of linkages they possess and then some descriptions in terms of that particular polysaccharide. Now first we have cellulose and we know that cellulose, its origin is in plants. We're gonna say when it comes to cellulose, it's unbranched and it possesses beta 14 glyco cytic linkages. So here are our 14 linkages. Now, here we're going to say that they compose plant cell walls and they typically have thousands of repeated units together, thousands of them linked together in this beta 14 linkage setup. Next, we have kin kin is also a structural support polysaccharide. Its source is various because it's connected to anthro pods. Um like lobsters, it's connected to insects. It's even connected to fungi, fungi. Now, here we're gonna say just like cellulose, it's unbranched and it has beta 14 linkages. What's the difference? The difference is that in cellulose in position two, we have these oh groups on each of these rings that oh group is modified when it comes to king. Here, it's gonna have an amide or amide group instead. So we have NH connected to a carbon connected to ach three and that's what's happening here for each one. Here. We'd say that it forms the exoskeletons of like these lobsters and different insects, but just like cellulose, it's involved in cell walls but not of plants, of fungi. So it deals with fungi, fungal cell walls, alos and then we have Amy Lope and then we have Glycogen. These are all dealing with energy storage. The first two are connected to plants. The last one is connected to animals. Us, if we take a look here at Alos here, we're gonna say that it is unbranched but it has alpha 14 glyco cytic linkages. So these are alpha here. We're gonna say that this one here. This makes up about 20% of all plant starch starch, plant starch has these two as its primary components, 20% of it coming from Ame the rest of it coming from Amlo pin alo Pectin is a bit different. It still has alpha 14 glyco cytic linkages, but it also has alpha 16 glyco cytic linkages. This one again makes up about 80% of all plant starch. It has some branching in the form of this alpha 16 Glyco cynic linkage. Then finally, we have glycogen which is related to animals to us. We have the same types of connections. We have our alpha 14, not alpha 16 linkages. This is kind of a nickname for it is animal starch because of the similar branching. But our branching occurs much more often. We have much more extensive branching. Every certain number of monosaccharide units. We have a 16 branching group. We have much more than we would for a plant. And that's because animals are more, more mobile, we move more. So we require more energy. These branching sites are a way of packing in more monosaccharide. So that when we need that energy, we can break down these sugars to supply the animal with the much needed energy they need to move, right? So just remember these last 2 may be similar, but Glycogen has way more branching involved, right? So these are our most common types of polysaccharides, those that are in structural support and those that are in energy storage and then they have different sources. Whether they be from plants various or animal.
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example
Polysaccharides Example 1
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In this example, we need to match each of the following statements with the correct polysaccharides. So option one, we have Amycin and Glycogen two, we have just glycogen and three, we have cellulose. All right. So for the first one, it says it's an unbranched polysaccharide composed of beta 14 glyco cytic linkages. When it comes to Amy Lectin and Glycogen, they have branching groups, they have alpha 16 branching groups. So they would be out. That means the answer is option three, cellulose has unbranched is an unbranched polysaccharide. And also it's the only one with beta linkages for the next one. A polysaccharide that is stored in mush muscle tissues. All right. So where do these polysaccharides come from? And we think about it, we'd say that glycogen has to be the answer here because glycogen source is animals and we're talking about muscle tissues, we wouldn't talk about muscle tissues with plants. Here we talk about fibrous tissue that's different. So here this would have to be two. And then finally, this is a polysaccharide containing alpha 14 and alpha 16 glyco cytic linkages. This is true of both Amycin and Glycogen So option one would be our final answer here. So this is how we would basically match each of the statements with the correct polysaccharide.
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Problem
Problem
Which plant-based polysaccharide possesses only a-1,4 glycosidic linkages?