Draw in the R-groups from memory for each of the polar amino a...

Question

Draw in the R-groups from memory for each of the polar amino acids.

Structures of polar amino acids: Serine, Threonine, Cysteine, Asparagine, Glutamine.

Accepted Answer

So this practice problem wants us to draw in the r groups from memory for each of the polar amino acids. So when we think about the polar amino acids, we think about the North Pole and we think about our mnemonic for memorizing the 5 polar amino acids, which is Santa's team crafts new quilts. And so we know that even though Santa and his team know that alcohol is a serious threat, where the serious here is for serine and the thre is for threonine, that Santa and his team, they can have alcohol in moderation while they're crafting their new quilts and it's totally fine. And so that helps us remember that both serine and threonine are the only 2 amino acids of these 5 that actually have alcohol groups in their R groups. And so what you'll recognize is that because S here, serine, is the first amino acid of this group, it's the leader amino acid of this group. And so, serine is really going to be following our leader amino acid, alanine. And so serine is literally just alanine or, CH 2 here with an alcohol group branching off of it. And so, it will have an Oh group and really, that is it for serine structure. Now, next what we have is TNT is for threonine, and we know that threonine is also going to have an alcohol group. And really, threonine structure is based right off of serine structure. So, they feed off of each other here. And so threonine is really going to look just like serine here with the alcohol group coming down. But instead of having 2 hydrogens, it's only going to have 1 hydrogen coming off, and then on the other side, it's going to have a methyl group, a c h three group. And so we can remember that threonine has three parts surrounding its central carbon atom in its R group. And so the 3 groups are the hydrogen, the alcohol group, and the methyl group. And so that is it for threonine structure. Now moving on, next what we have is the c, and the c is for cysteine. And in our mnemonic, we know that the cysteine is really a hammer, and we know that it's actually, standing for crafting. It's that crafting hammer. And that crafting hammer spends a lot of quiet time in the Sistine Chapel, which is a church. So when we think about the North Pole, we think about Santa Claus, we think about Christmas, and we think about church. And then, we know that Sistine spends a lot of quiet time in the Sistine Chapel. And so whenever somebody makes a noise, cysteine is always like, Shhh. And so literally cysteine is just our leader amino acid alanine, so CH 2, with a SH group coming off, or an SH group. And so literally, this is cysteine's structure. Now moving on, next what we have is the n, and the n is specifically for asparagine. And so asparagine's R group, we know has an, amide group in it. And so we can, remember that because it's one letter code, the n, has these 2 parallel lines in it, and those two parallel lines remind us of a double bond. And the nitrogen that's present, tells us that there's a double bond with a nitrogen, and that reminds us of the amide group. And so, literally, asparagine is just our leader amino acid alanine with an amide group coming off. And so, we can draw alanine, so we know the hydrogens are gonna change it too. And then it's gonna have an amide group branching off, which is just a c double bond o with an NH 2 coming off. And so this here is our amide group, and you can see that it's essentially just alanine with an amide group branching off, and that is it for asparagine structure. Now, moving on, what we have next is the q, and the q is for glutamine. And glutamine structure is really based right off of the asparagine structure, kind of like how threonine structure is based off of serine structure. And so with glutamine, because it has the glute in it, the glute reminds us of our gluteus maximus or our butt section. And so if you're missing the butt section, you're going to be a little bit shorter, but because glutamine actually has the glute in it, it's going to have an extra butt section or an extra CH 2. And so, essentially it's going to be exactly the same as a spare gene, but it's going to have an extra CH 2. So we can go ahead and start to draw its structure over here, so it's going to be a CH 2. We know that it's going to have an extra CH 2. And then it's going to have the amide group at the very bottom. And so this is it. So an n h 2. Let's make that a little bit clearer here. Perfect. So this is it for a, glutamine structure. You can see we have the amide group at the bottom, and it has an extra c h 2 that asparagine doesn't have because glutamine has that extra glute in it. And so that is it for glutamine structure. And so that concludes this practice problem, and hopefully that helped you guys refresh a lot of those memory tools that we learned in our previous lesson video, and we'll be able to get even more practice utilizing all of these concepts and memory tools as we move along through our course. So I'll see you guys in our next video.

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Draw in the R-groups from memory for each of the polar amino acids.

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