Stereochemistry of Monosaccharides

in this video, we're going to begin our lesson on mono sacha ride stereo chemistry. So before we actually get started, I want to point out that most of the information in this topic is actually going to be review from your old organic chemistry courses. And I want you guys to note that way back in some of our previous lesson videos, we actually did an organic chemistry review for your biochemistry course, and we covered a lot of organic chemistry topics in MAWR detail. And so, if you're looking at a lot of the terminology and vocabulary on this page and it's completely unfamiliar to you, then be sure to go check out those older lesson videos on organic chemistry review before you actually move on with this video here. Alright, so that being said, let's go in and talk about what we have on this page. And so it's important to note that the three D structures of linear mono sacha rides are commonly displayed on pieces of paper using Fisher projections, and so throughout our lesson on carbohydrates, we're going to continue to see lots and lots of Fisher projections, and so notice over here on the far left. We've got this really cool image to help remind you guys of an important feature, Fisher projections. And that is that all of the horizontal bonds that go from side to side and every Fisher projection are actually popping out of the page as wedges. And so notice Over here we have this three dimensional sugar molecule, and we're shining this flashlight down on the three d sugar molecule to create this shadow of the sugar molecule on this yellow plane. And if we were to draw that shadow onto a piece of paper, we would get the Fisher projection. And so notice that the horizontal bonds here in the Fisher projection correspond with bonds that air popping out of the page as wedges. And so that's important to keep in mind when we're considering the stereo chemistry of Fisher projections. So now we can move on to the terms that we have over here in this table on notice, the first time that we have our constitutional ice MERS and recall that ice MERS or just different molecules with the same chemical formula. So constitutionalism er's are on Lee going to differ in their constitution or the connectivity of the atoms and a classic example are glycerol to hide and die hydroxy acetone or D J, and noticed they have the same chemical formula but different connectivity of atoms. Now, the next time that we have our stereo, I summers and again these air eizember, so they have the same exact chemical formula. But this time they don't differ in the connectivity of the atoms. Instead, they differ in their three dimensional space, which is what the prefix stereo is referring to. And so notice that these two molecules Onley differ in the three dimensional space of this hydroxyl molecule that we see over here. Now, the next term that we have is, uh, in the anti MERS and an anti MERS air. Just a specific type of stereo is, um er and recall that they are just non super imposible mirror images. And so a classic example our our hands. So our left hand is a mirror image of the right hand and they're non super imposible since we can't perfectly overlap them in space when they're facing the same direction. And so that applies to these molecules over here D glass or outside and Elvis or Al Jihad, which are mirror images of one another. And again, we cannot superimpose them or overlap them in space. Now, the last time that we have down below our Dia stereo MERS, which are really just another type of stereo I summers. But Darius Dia stereo MERS this time are not mirror images, and so we can see down below that these two structures air not mirror images of one another because they differ in their three dimensional space. The configuration here. And so that's why we've got this broken mirror to represent the Dia stereo. And so this here concludes our introduction to the stereo chemistry of mono sack rides. And again, if you need a review, make sure to go back and check out those older lesson videos. So I'll see you guys in our next video.

in this video, we're going to remind you guys how to calculate the number of stereo is a MERS that a molecule has. And so the number of stereo I summers that a molecule has is going to be equal to two raised to the power of n, where N is equal to the number of Cairo carbons that the molecule has. And so recall from your previous organic chemistry courses that a Cairo carbon is literally a carbon atom that is covertly bound to four distinct chemical groups or for different chemical groups. And so, in our example, down below, we're going to circle all of the Cairo centers or Cairo carbons, for that matter, these air synonyms of one another. And we're going to determine how maney stereo ice summers each of the following molecules has. And so we'll start with this molecule over here on the left hand side and looking at its first carbon on the left. What we need to realize is that there are two hydrogen atoms branching off that aren't being shown, and that means that there are two bonds leading to the same chemical group of a hydrogen atom, and so that means that this carbon atom does not have four distinct chemical groups, since it has two of the same chemical groups, and the same logic applies for this carbon atom appear. It's also bound to two hydrogen atoms that aren't being shown, which means that it is not a Cairo carbon. Now, this carbon atom right here is also not a Cairo carbon because it has a double bond, meaning that it has to bonds leading to the same chemical group, which means that it won't have four distinct chemical groups. And so the Onley Cairo carbon in this entire molecule right here is this carbon right there that's circled. And so notice that the hydroxyl group going down is different than this group going to the right, which is different than this group going to the left, which is different than the invisible hydrogen atom that isn't being shown. And so this circled carbon is a Cairo carbon because it has for distinct chemical groups. And so now that we've circled all of the Cairo centers in this molecule, let's go ahead and calculate the number of stereo I summers and as we mentioned above, number of stereo ice MERS is to to the end. So too on then n is the number of Cairo carbons which is one for this molecule. So to race the one and that is of course, equal to two. So there are two stereo I stammers that this molecule has now looking at this molecule over here we could do the same looking at each Cairo looking for the Cairo carbons. And if we look at this carbon atom right here on the far left, it has a double bond which we already know means that it's not going to be a Cairo carbon. And then when we look at this carbon over here, notice that it has two hydrogen atoms branching off, which means that it won't have four distinct chemical groups. And of course, that means that it's not going to be a Cairo carbon. And so the Onley Cairo carbons are right here in these positions and noticed that all four of these carbon atoms are Cairo because they all have four distinct chemical groups attached. And so now that we've identified the four Kyrill centers in this molecule, let's calculate the number of stereo ice MERS, which again is to race to the end. And so we have to, and this time is going to be four. Since there are four Cairo carbons, and if you take your calculators and type in to race to the fourth power, you'll get an answer of 16. So this molecule has 16 stereo ice summers. And so this here concludes our lesson on how to calculate the number of stereo I summers and will be able to apply this moving forward in our practice problems, so I'll see you guys in our next video.

all right, so in this video, we're going to introduce MONOS, aka Ride A Palmer's. So what in the world are a Palmer's? Well, A Bombers are really just a specific type of dia steri, um, and recall from our previous lesson videos that dia steri a MERS are just stereo items that are not mirror images, which means that farmers are also not mirror images. And so to remind you that the bombers are not mirror images, we have this big broken mirror here toe again remind you that they're not mirror images. But more specifically, embalmers are going to be die astir rumors that differ on Lee in the configuration of just any one single Cairo carbon. And so the Onley difference between two epi Mars is again going to be the configuration of just one single Cairo carbon. So if we take a look at our image down below, you can see that we have an example of a pair of a plumber's. And so on the left hand side we have the structure for D glucose. And on the right hand side, we have the structure of D manos and D glucose and de manos differ from each other and on Lee, the configuration of one single Cairo carbon. And that is the Cairo carbon that is highlighted in this pink box. And so de manos. Instead of having the hydroxyl group pointing to the right of the Fisher projection like what D Glucose has? De Manos has its hydroxyl group pointing to the left, and instead it's hydrogen is gonna be pointing to the right. And so because de manos and D glucose differ from each other again Onley in the configuration of just one single Cairo carbon that makes them a Palmer's. And again, all embalmers are not going to be mirror images. And so that concludes our introduction to mono Sacha Ride a Palmer's and we'll be able to get some practice utilizing this concept as we move forward in our course. So I'll see you guys in our next video

in this video, we're going to do a review of the different types of MONOS, aka Ride Ice Hammers. And so really, none of the information in this video is new information. It's all review from our previous lesson videos. And so if you already feel comfortable with all of the terms on this page, then feel free to skip this video if you'd like. However, if you're struggling even just a little bit with any of these terms, then feel free to stick around because this is an excellent way to be ableto visualize how all of these different terms relate toe one another. Alright, so let's get started with this flow chart and notice at the very top. Here we have the term ice summers, which recall are just different molecules with the same exact molecular formula. And really there are two branches of ice summers. We have the constitutionalism er's and we have the stereo. I summers now constitutionalism er's are going to be ice summers that have the same exact chemical formula. But they have different connectivity of the atoms, and a classic example is glycerol to hide and die hydroxy acid tone where you can see just by focusing on the Carbonnel group that they have different connective ity of the atoms. They're connected in a different way now. The other branch of Ice summers are the stereo is a MERS, which actually have the same exact connectivity, unlike constitutionalism er's. But they have different spatial three D arrangement, and that's why we've got these three D glasses over here. Now stereo is a MERS. Themselves can also be broken up into two different categories, and those are the Ananta MERS over Here and the DIA hysteria MERS over here. And so an ant Humor's recall are non super imposible mirror images and so clearly here we have a mirror, and these two molecules are mirror images of each other. And so this is going to be de glycerol died. And this is L. Glaser Aldo Hide, and this is a classic example of an anti MERS. Now die a stereo MERS. On the other hand are stereo is summers that are not mirror images such as, for instance, D glucose and deep Paltrow's notice that they have to Cairo carbons uh, that are not going to be opposite configurations, and so that makes them die a stereo MERS. Now, as we already mentioned, a very specific type of dia steri Um er is the Obama. And so a bombers are going to be dia stereo MERS that have different configuration at any one Cairo carbon. And so if the two molecules Onley differ in the configuration of one Cairo carbon that will make them UNEP immer and again, a classic example is D glucose and D manos, which Onley differ in the configuration of this one hydroxyl group at the C two carbon. And so really, this concludes our flow chart, and we'll be able to get some practice applying all of these concepts in our next couple of videos, so I'll see you guys there.