The shell of a shrimp is composed of chitin. If you eat a boiled shrimp without removing the shell, will your body break the shell down into its component sugars? Explain. (Hint: Compare chitin’s structure to that of amylose and cellulose.)

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Hello, everyone and welcome back. Our next problem says in a biochemistry class, the student learns about the structural components of fungal cell walls. The most important component of the fungal cell wall is Chitin. It is structurally similar to cellulose, but it cannot be broken down into a simpler component. Sugar. Explain choice. A says Chitin cannot be broken down due to its disulfide bonding. Unlike cellulose, Chitin is composed of N acetylglucosamine units, which makes it more susceptible to enzymes that won't break down polysaccharides like cellulose BK cannot be broken down due to the presence of alcohol groups. Unlike C cellulose Chitin is also composed of amine units which makes it less susceptible to enzymes that won't break down polysaccharides. Like cellulose. Sea kitten cannot be broken down due to its branched structural composition. Unlike cellulose, Chitin is composed of branched galactose units which makes it less susceptible to the enzymes that break down polysaccharides. Like cellulose or D kitten cannot be broken down due to its unique structural composition. Unlike cellulose, Chitin is composed of n acetylglucosamine units, which makes it less susceptible to the enzymes that break down polysaccharides like cellulose. Well, let's think about the similarities and differences between cellulose and chin and the big difference is they have different subunits. So cellulose is composed of glucose monomers, but the units of Chitin while based on glucose are actually in acetylglucosamine units. So we know our answer has to be one of choice a or choice d both of which describe kitten as being composed of these type of units. So let's just take a quick look at this structure so that we can see have in mind what that looks like. So I've pasted in the structures of cellulose on the left here, saw you was and there's just two representative units. Here. We have two glucose units and they're connected by a beta 14 G like acidic bond between the units. And then when we look over here on the right, that's the structure of Chitin. And we see it's, you know, very similar, there's this ring based on glucose, but then with the addition and we'll highlight this in pink of this amid structures here. So there's an NH and then ac double bond to O and then ch three making those units. And acetylglucosamine units. Now notice that the bond here in kitten is also a beta 14 gly acidic bond. So we know that the enzymes that break down polysaccharides and their monosaccharide break the glyco cytic bonds. So why wouldn't cellulose, which is what breaks down cellulose be able to break the same bond in Chitin if it's the same exact type of bond. And the answer is those different structural units because remember that our enzymes are very specific to the shape of the substrates. And the difference in the sub units there makes the shape different enough that the cellulose can't, you know that the chin will not fit in the cellulose active site. And therefore it won't be able to break it down. So that's going to lead us to our answer choice here, which is choice D that it cannot be broken kit and cannot be broken down to the unique structural composition. It's composed of these anise glucosamine units which make it less susceptible to the enzymes that break down polysaccharides like cellulose. When we look at choice. A first of all, it says it cannot be broken down due to its disulfide bonding. We don't have any sulfur here. There's not disulfide bonding going on correctly describes the units. But then it says this makes it more susceptible to enzymes that won't break down polysaccharides like cellulose, but that's backwards and doesn't make any sense because it's the cellulose that gets broken down and the Chitin that does not. So that's why A is incorrect. Choice B makes the same mistake. And they explain about enzymes saying Chitin is less susceptible to enzymes that won't break down polysaccharides. So that's already incorrect. And then the first part of it says it cannot be broken down due to the presence of alcohol groups, but cellulose also has alcohol groups, of course. So cellulose also has these and then it goes on to say Chitin is also composed of amine units. Well, it does have this amine in it but this is not the correct description of what's going on. So rule out choice B and then finally choice C has the correct description of the enzymes. Says Chitin is less susceptible to the enzymes that break down polysaccharides like cellulose. So that part is correct. But then it says kitten cannot be broken down due to its branched structural composition saying unlike cellulose, Chitin is composed of branched galactose units. Well, this is incorrect. So we saw it's composed of N acetylglucosamine units and neither of them is branched, both cellulose and Chitin. Another structural similarity is that they are composed of straight chains or this making this fiber structure packed in layers. And you can compare that to if there were alpha 14 gly acidic linkages like an alos that creates a helical structure. So once again, why is it that kitten despite its similarity to cellulose in its structure cannot be broken down into a simpler component structure. And the answer is that it cannot be broken down due to its unique structural composition. And Chin is composed unlike glucose of n acetylglucosamine units, which makes it less susceptible to the enzymes that break down polysaccharides like cellulose. See in the next video

The shell of a shrimp is composed of chitin. If you eat a boiled shrimp without removing the shell, will your body break the shell down into its component sugars? Explain. (Hint: Compare chitin’s structure to that of amylose and cellulose.)

Verified video answer for a similar problem:

Key Concepts

Chitin Structure

Digestive Enzymes

Comparison with Amylose and Cellulose