For each of the following, give the monosaccharide units produ...

Question

For each of the following, give the monosaccharide units produced by hydrolysis, the type of glycosidic bond, and the name of the disaccharide, including α or β:

a. Chemical structure of a disaccharide showing monosaccharide units and glycosidic bond details.

Accepted Answer

All right. Hello everyone. So this question says, given the following disaccharide, whose structure is shown here for part one, when the given disaccharide undergoes hydrolysis, determine the two monosaccharide units produced. Part two says to determine the type of glyco cytic bond that holds the disaccharide together. And part three is asking to determine the name of the disaccharide. And if it is alpha or beta, now, just for the record by analyzing the structure of our disaccharide, we can see that we have this oxygen atom in between our two ring structures, right, that oxygen atom marks our glyco cytic bond, which we'll focus on later on. But for now, let's go ahead and address part one, which is asking about the monosaccharide units of this disaccharide if we were to put it through hydrolysis. Now, hydrolysis, if you recall is the addition of water to break a bond. So in this case, water would be added to our disaccharide to break the Glyco cytic bond and release our two separate monosaccharide. So here by analyzing both monosaccharide here individually, we can see that both of them have a primary alcohol group that is pointing above the rink So, just to go ahead and repeat that we have a primary alcohol group, we have a CH 20 And that's pointing upwards, this indicates that this is going to be D isomers. Both monosaccharide will be D isomers. If they were pointing down, they would be L isomers. And so considering now the monosaccharide unit on the very right side, excuse me, on the left, just to start off, we can see that the hydroxy groups of carbons 23 and four are alternating because of that, we can conclude that the monosaccharide unit on the left side must be the glucose. So now looking on the right side, we can see that the positioning of the hydroxy groups inside of the ring is consistent with the fructose. So we have d glucose and D fructose here. So now let's go ahead and switch our focus to the glyco cytic bond. And so the question is what type of glyco cytic bond is holding our dy saccharide together? Well, when reading out the question specifically part three here it mentions alpha versus beta configuration. And while that is going to be important for part two, specifically, there's a bit more information that we need to take note of. First, it's important to go ahead and keep track of the carbon atoms inside of the inside of your rings by numbering them. So here I'm numbering glucose from 1 to 6. And we can see now that carbon number one is participating in the glyco cytic bond doing the same. Now for fructose, we can see here that carbon two of fructose is participating in the glyco cytic bond. And so going from left to right in building our name here for the glyco cytic bond, it's going to be in parentheses and I would write one arrow two because on the left we have glucose which is contributing carbon number one. And on the right, we have fructose which is contributing its second carbon. And so at each position, each carbon that's participating in the glyco cytic bond has to be distinguished between alpha or beta. So let's go ahead and briefly talk about that and lets start off with buhos actually. So to understand the configuration of glucose in this disaccharide, I want to understand the relationship between the substituents branching off of carbon one and carbon five. My substituents are the oxygen participating in the glyco cytic bond and the primary alcohol group respectively. And so, analyzing these substituents, I can see that they're both trans or they're trans to each other. I should say because the oxygen of the glyco cytic bond is pointing downwards and the primary alcohol group branching from carbon five is pointing upwards. And so because the glucose subunit has that translation between those two substituents, that's alpha configuration. And so the alpha symbol would go before the number one in parentheses. So now I'll do the same thing with fructose I'll be examining the substituents branching off of carbons too and five. So, from the perspective of fructose, now, we can see that the oxygen of the glyco cytic bond points downwards. And so does the primary alcohol group branching off of carbon five because now there's sis this is beta configuration. And so the beta symbol would go after the number two in parentheses. So that's alpha 12 beta. And now for part three, we can finish off with the name of our di saccharide. Now, when naming a disaccharide as a whole or as a unit, it's important to recognize that we're going to be focusing our attention on the second monosaccharide in this case, fructose. And so fructose, as mentioned before was in the beta configuration because the two substituents branching off of carbons two and five were cysts, they were on the same side of the ring. So that's beta configuration. And if you recall a, a disaccharide composed of glucose and fructose is called sucrose. And so our answer for part three which completes this video is going to be beta sucrose and there you have it. So now we have the answers to parts 12 and three. So with that being said, if you watch this video all the way through, thank you so very much. And I hope you found this helpful

For each of the following, give the monosaccharide units produced by hydrolysis, the type of glycosidic bond, and the name of the disaccharide, including α or β:
a.

Key Concepts

Monosaccharides

Glycosidic Bonds

Disaccharides

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