In this video, we're going to begin our discussion on derivatives of monosaccharides. So recall that in our previous lesson videos, we mentioned that there are simple sugars in nature that have the exact formula here, CnH2nOn, but there are also complex sugars in nature that can actually deviate from this exact formula. And so really, these complex sugars are just derivatives of the simple sugars. And so, we can call these monosaccharide derivatives or otherwise complex monosaccharides. Now, your professors and your textbooks, sometimes they'll say monosaccharide derivatives, other times they'll say complex monosaccharides. And so now you guys know what they're referring to. And so really, these monosaccharide derivatives or complex monosaccharides are just chemically modified monosaccharides. And so if they're chemically modified, that means that they can deviate from this exact formula here and so what we'll see is that these monosaccharide derivatives, they will take the hydroxyl groups of simple sugars and replace them with other chemical groups. Such as, for instance, phosphate groups, carboxylic acids, or amino groups. And so when it comes down to it, really there are just 5 major groups of monosaccharide derivatives. And so you can see those 5 major groups down below in our image. And so the first is going to be sugar phosphates. The second is going to be sugar alcohols. The third is going to be deoxy sugars, the fourth is going to be amino sugars, and the fifth are going to be sugar acids. And so as we move forward in our course, we're going to talk about each of these 5 different groups of monosaccharide derivatives in their own separate videos. And so we'll start with the sugar phosphate, so I'll see you guys in our next video.
Derivatives of Monosaccharides - Online Tutor, Practice Problems & Exam Prep
Derivatives of Monosaccharides
Video transcript
Derivatives of Monosaccharides
Video transcript
Alright. So, the first group of monosaccharide derivatives that we're going to talk about are the sugar phosphates. And so as you may have already guessed, sugar phosphates are just carbohydrates that are covalently attached to phosphate groups. As we move forward through our course, sugar phosphates are going to make up part of the structure of nucleotides. Of course, nucleotides make up the structure of nucleic acids such as DNA. Notice below we're showing you a DNA molecule, and we're zooming in on this region of the DNA molecule here. You can see that we have these carbohydrates or these sugars, and notice that the sugars are covalently attached to phosphate groups. You can see that we have another sugar here that is also covalently attached to another phosphate group. It's true that the structure of DNA does include sugar phosphates. Later in our course, we'll talk more details about the exact structure of DNA, but for now, we're focusing just on sugar phosphates.
You'll also note that later in our course when we're talking about carbohydrate metabolism, you'll find that sugar phosphates are going to be an important intermediate in the pathways of both carbohydrate metabolism, and carbohydrate catabolism; breaking things down and building things up. Again, we'll talk more about this later in our course. If you take a look at this box over here, what you'll notice is that we've got this D-glucose molecule here, which is a carbohydrate that we can metabolize. Notice that through phosphorylation, we can take the D-glucose molecule and get a D-glucose 6 - phosphate molecule. Notice that the D-glucose molecule is now covalently attached to this phosphate group here. We'll see many different intermediates in the pathways of carbohydrate metabolism and catabolism that include these sugar phosphates. This sugar phosphate can continue through carbohydrate metabolism through the glycolysis pathway here. But again, we'll talk a lot more about carbohydrate metabolism later in our course, and right now, we're just focusing on sugar phosphates. They make up part of the structure of DNA, and they're going to be important intermediates and carbohydrate metabolism and catabolism.
That concludes our introduction to sugar phosphates. In our next video, we'll be able to talk about the next group of sugar derivatives, which are the sugar alcohols. So I'll see you guys there.
Derivatives of Monosaccharides
Video transcript
Alright. So the next group of monosaccharide derivatives are the sugar alcohols, also known as aldotols. Sugar alcohols or aldotols are just sugars whose carbonyl group is reduced to an alcohol group or an OH group. When this happens, every single carbon atom of the sugar is going to have its own alcohol group. Usually, these sugar alcohols or aldotols are going to have the suffix -itol added to the end of the name.
If we take a look at our example of sugar alcohols down below right here, notice that we have the linear monosaccharide D-glucose right here. Through the process of reduction, we can reduce this aldehyde group into an alcohol group, an OH group here. We're also adding on this hydrogen atom right here. We're able to generate the molecule sorbitol which, notice that when we look at every single one of its carbon atoms, they all have their own alcohol group and so it is also easy to identify sugar alcohols or aldotols. That concludes our brief introduction to sugar alcohols and aldotols, and I'll see you guys in our next video when we talk about the third group of monosaccharide derivatives, deoxy sugars.
What is the name of the sugar alcohol produced when D-ribose is reduced?
Derivatives of Monosaccharides
Video transcript
Alright. So the third group of monosaccharide derivatives that we're going to cover are the deoxy sugars. Now, deoxy sugars are just going to be sugars that are missing at least one hydroxyl group, and usually, the hydroxyl groups are missing due to the replacement with hydrogen atoms. A classic deoxy sugar is the sugar 2-deoxy-D-ribose. This prefix "deoxy" is used to indicate deoxy sugars. Now, 2-deoxy-D-ribose is the primary building block of DNA in all organisms, and so later in our course, when we focus our attention on nucleic acids and DNA structure, we will definitely revisit this idea of deoxy sugars.
If we take a look at our example down below, you can see the deoxy sugars in DNA. Notice over here on the left, we have the furanose form of beta-D-ribose. Notice that this alcohol group on C2. If it is replaced with a hydrogen atom or simply if we just remove the oxygen here, then what we can get is deoxyribose. We can convert beta-D-ribose into beta-D-2-deoxyribose just by replacing the alcohol group with a hydrogen atom on the C2 carbon. This 2 indicates that it's the second carbon here that is going to have the alcohol replaced. Beta-D-2-deoxyribose here is the sugar found in DNA. You can see that we have DNA over here, and we're taking a zoom-in of the DNA. You can see that, within the structure of DNA, we do have this deoxy beta-D-2-deoxyribose in there.
This concludes our introduction to the deoxy sugars group of monosaccharide derivatives. In our next lesson video, we'll talk about the fourth group of monosaccharide derivatives which are the amino sugars. So I'll see you guys there.
Derivatives of Monosaccharides
Video transcript
Alright. So the fourth group of monosaccharide derivatives that we're going to talk about are the amino sugars. Amino sugars are just sugars that are going to contain an amino group rather than containing a hydroxyl group at that position. As we'll see moving forward in our course, amino sugars are going to be commonly found in many oligosaccharides as well as polysaccharides. For example, chitin, which is a polysaccharide that we're going to talk more about later in our course. These amino sugars usually have the suffix "amine."
If we take a look at our example below of amino sugars, notice that we're starting off with a beta-D-glucose molecule over here. If we replace one of the hydroxyl groups here with an amino group, what we've got is beta-D-glucosamine, and notice that the ending has this suffix "amine" in it. This concludes our introduction to amino sugars, and in our next lesson video, we'll talk about the fifth and final group of monosaccharide derivatives, the sugar acids. So, I'll see you guys in that video.
Derivatives of Monosaccharides
Video transcript
Alright. So in this video, we're going to talk about the 5th and final class of monosaccharide derivatives, which are the sugar acids. Sugar acids are just carbohydrates with carboxylic acid groups, and there are 3 main types of sugar acids that you should know. The first type is the aldonic acids. The second type is the uronic acids, and the third type is the alderic acids. You'll notice that I intentionally capitalized the letter A in Aldonic, the letters U and R in Uronic, and the letters A and R in Alderic. That's because we're going to utilize this as a memory tool to help us distinguish between these three different types of sugar acids. But before we introduce that memory tool, let's first go ahead and identify what each of these 3 sugar acids is.
The aldonic acids are going to be aldoses whose C1 aldehyde group is oxidized into a carboxylic acid. Aldonic acids usually have the suffix -onic. Now the next class, uronic acids, these are just sugars whose highest numbered carbon is oxidized into a carboxylic acid. Uronic acids usually have the suffix -uronic. And then, of course, last but not least, we have the alderic acids, and these are going to be sugars whose lowest and highest numbered carbons are oxidized to carboxylic acids. Alderic acids are usually going to have the suffix -aric.
What you'll notice again, is we intentionally capitalize the letters that you see up above here. The A is the first letter of the alphabet and so that reminds us that aldonic acids are going to have their first carbon atom, the C1 aldehyde, oxidized to a carboxylic acid. So you think the first letter of the alphabet here with aldonic is the first carbon is oxidized. Now, uronic, we capitalize U and R, which are two letters that are towards the end of the alphabet. So they're closer to the end of the alphabet. And so this reminds us that it's the highest numbered or the carbon atoms towards the end of the sugars that are going to be oxidized to carboxylic acids. And then notice that aldaric acid contains the letter A, which is the first letter of the alphabet, and the letter R, which is a letter towards the end of the alphabet. And so this reminds us that aldaric acids have both the lowest numbered carbon and the highest numbered carbon oxidized to carboxylic acids.
If we take a look at our example down below, we're going to label the following sugar acids. Notice over here on the far right in this box, we're starting on the left with a D-glucose molecule. Notice that we have oxidation only at the C1 carbon, the aldehyde group that's at the top, the C1 aldehyde. And so it's being oxidized to a carboxylic acid. Of course, that is going to classify this because it's only the lowest numbered carbon. This is going to be an Aldonic acid. And of course, the suffix that it uses is -onic. And so this is going to be gluconic acid. So we've converted D-glucose into D-gluconic acid.
Now, in this next box over here, notice again we're starting with a D-glucose molecule once again just like we started with D-glucose over here. Except this time, notice that we have oxidation at the C6 Carbon, which is the highest numbered carbon. And so the highest numbered carbon being oxidized to a carboxylic acid is going to be a uronic acid. What helps us remember that is again, the letters 'U' and 'R' are towards the end of the alphabet, and so this is at the end of the sugar molecule here that's being oxidized and of course, the suffix that's typically used for uronic acid is just -uronic. So this is going to be D-glucuronic acid. So we've converted D-glucose into D-glucuronic acid right here.
Last but not least, over here in this last box, notice once again, we're starting with a D-glucose molecule just like the previous two. Except this time, notice that we have oxidation at both C1 and C6. So, we have oxidation at both ends, at the lowest and the highest numbered carbons, being oxidized to carboxylic acids. Again, because aldaric has the A and the R, that reminds us that it has the beginning and towards the end being oxidized. So this is again going to be an aldaric acid. And of course, the suffix for aldaric acid is just -aric. And so this is going to be D-glucaric acid. So we've converted D-glucose into D-glucaric acid.
That is it for our introduction to the sugar acids in the 3 types: aldonic, uronic, and aldaric. We'll be able to get a little bit of practice with these concepts in our next video. See you guys there!
Classify the following sugar acids as aldonic, uronic or aldaric acids: