1
concept
Starch
3m
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in this video, we're going to begin our lesson on the poly Sacha ride starch. So it turns out that the poly Sacha ride starch actually has two different forms. And those two different forms of the poly Sacha ride starch are the AM alos form and the, um alot pectin form. And so notice here in our table for the poly Sacha Ride column. We're showing you starch, but we're also telling you that starts has two different forms the Melo's form and the Melo pectin form. And what you'll notice here in this table is that these first columns here that air boxed in applied to all forms of starch am alos and amel, OPEC and included. And so they are going to be exactly the same when it comes to all of these boxes that we have box in. And so really, the Onley way, the ambulance and amel OPEC and differ from each other is in this last box over here. And so we'll talk about that when we get there. But let's go ahead and get started. So, um, all forms of starch am alos and ml OPEC that included are going to be home Oh, Polly Sacha rides Which of course, we know from our previous lesson videos just means that it's going to be made up of just one single type of repeating sugar unit and that repeating sugar unit is going to be de glucose for both the AM alos and AM alot pectin form. Now all of these d glucose residues in the starch molecules are going to be linked to each other via Alfa 14 Glick acidic linkages, which is a little bit different than the Glick ascetic linkages of our previous Polly Sacha rides that we talked about. And so, in our course, the Alfa configuration in the Glock ascetic linkage of Polly sack rides is going toe indicate an energy storage function. And so starch both am alos and am alot pectin eyes going to serve as an energy storage molecule and plant cells. And so the organism is of course, going to be plants. Now again, notice that for all of these boxes here, they're going to be identical for both forms of starch am alos and Emel OPEC in and again, the only way that they differ is through this last box Over here the branched box. And so this is what distinguishes am alos from Amla pectin. And so am alos uh, in terms of being branched, it's actually not going to be branch. So it has absolutely no branching in the AM alos form of starch. However, the AMLO pectin form of starches kind of pectin. It's like pecking all over the place, so it definitely is going to be branch. So in terms of branching, weaken, say yes and all of the branch points in M. L O pectin are going to be associated with Alfa 16 like acidic linkages which will be able to visualize a little bit better in our next a couple of videos when we talk about Pamela pectin specifically. But for now, this year concludes our table here for the two forms of starch am alos and amel OPEC. In and in our next lesson, video will be able to talk a little bit more about Melo specifically. So I'll see you guys in that video
2
concept
Starch
1m
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So in this video we can visualize How am alos is an un branch form of starch just like what we said up above in our chart in our last lesson video. And so when you take a look at this image down below, notice that it's representing the structure of am alos and notice that am alos structure is indeed on branch. It's just a long linear chain here Now notice. Over here Towards the end, we're showing you the AM alos does actually form this helical loops. But still, the change themselves are UN branch. And there's no side chains coming off of these, uh, am alos structures. And so, if we take a closer look at the individual sugar units here in Amorosa structure, you'll notice that all of these are just straight d glucose molecules. And they're all linked via these Alfa 14 Glick acidic linkages. Now, if we take a look at the dice aka right here that's found within, uh, am alos structure, uh, you'll note that this is a dice accurate that we talked about in our previous lesson videos. And so we have to d glucose molecules that are linked via an Alfa one forg like acidic linkage. This is, of course, gonna be the dice, aka ride mall toes. And so recall from our previous lesson videos, we said that maltose is digestible to most animals. And so if maltose is digestible to most animals, that's going to translate to starch, also being digestible to most animals. And so this year concludes our lesson on how am alos is an UN branch form of starch. And in our next lesson, video will be able to take a closer look at a Melo pectin, so I'll see you guys there.
3
concept
Starch
2m
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All right, So in this video, we can visualize How am alot? Pectin is really just a branch form of am alos And so the AM alot pectin branch points are going to occur on average, every 24 to 30 residues or so and they're going to be linked via Alfa 16 like acidic linkages instead of Alfa 14 Gleick aesthetic linkages. But again, this is on Lee going to occur at the branch points. And so if we take a look at our image down below notice, it's supposed to be representing am alot pectin structure and so notice. Here we have our main chain of am alot pectin And so it goes through like this and then coming off of the main chain. We have these branches that I'm highlighting here in blue and so all of these blue our branches off of the main chain. So this is really the main difference between am alot pectin which is branched and am alos, which is up above and is not branched. And so if we zoom in here on one of the branch points what you'll notice if we get rid of these colors here uh that the branch point right here is connected to the main chain via an Alfa 16 Gleick Ascetic linkage. And really, it's on Lee These branch points that are going to contain the Alfa 16 linkages. And so these circled branch points and red down below will also have Alfa 16 Gleick acidic linkages. But all of the other linkages that we see are going to be Alfa 14 Gleick acidic linkages throughout the entire thing again, The Onley ones that are gonna have Alfa 1/6 like acidic linkages are the branch points. And so this year concludes our video on AM alot pectin structure and how it's a branch form of am alos and we'll be able to get some practice applying the concepts that we've learned in our next couple of videos. So I'll see you guys there
4
Problem
Which of the following is a structural polysaccharide in plant cells?
A
Glycogen.
B
Amylose.
C
Chitin.
D
Starch.
E
Cellulose.
5
Problem
Cellulose fibers resemble ___________ in proteins; whereas amylose’s structure is similar to _____________.
A
α-helices; β-sheets.
B
β-sheets; α-helices.
C
β-sheets; the hydrophobic core.
D
α-helices; β-turns.
E
β-turns; coiled-coils.
6
Problem
Cellulose, an unbranched β(1-4)-linked homopolysaccharide of D-glucose, differs from starch in that starch is:
A
A β-1,6-linked D-mannose homopolysaccharide that is branched.
B
A β-1,6-linked D-glucose homopolysaccharide that is unbranched.
C
An α-1,6-linked D-glucose homopolysaccharide that can be branched or unbranched.
D
An α-1,4-linked D-glucose homopolysaccharide that can be branched or unbranched.
E
An α-1,4-linked D-mannose homopolysaccharide that is branched.