How to Memorize Amino Acids - Online Tutor, Practice Problems & Exam Prep

To effectively memorize amino acids, utilize mnemonics like GAVLYMP for non-polar amino acids and "fat young whippersnappers" for aromatic ones. Understand the structures: glycine (G), alanine (A), valine (V), leucine (L), isoleucine (I), methionine (M), proline (P), phenylalanine (F), tyrosine (Y), and tryptophan (W). For polar amino acids, remember "Santa's team crafts new quilts" for serine (S), threonine (T), cysteine (C), asparagine (N), and glutamine (Q). Lastly, "dragons eat, knights riding horses" helps recall charged amino acids: aspartic acid (D), glutamic acid (E), lysine (K), arginine (R), and histidine (H).

Memorizing Amino Acids

In this video, we're going to consolidate all of the memory tools for memorizing all of the amino acids. So if you're looking for a good strategy to memorize all of the amino acids, I can recommend 2 things. The first is to continue to watch clutch prep biochemistry videos. The more you watch, the more you'll get a hang of these memory tools. And the second is to get lots and lots of practice. If you print and fill out this particular page and complete it from memory about 3 times or so, you'll start to get a better hang of the memory tools, namely GAVLYMP, which are the non polar amino acids. So, for the non-polar amino acids, the mnemonic is GAVLYMP, where each of these letters represents the one-letter code for all of the nonpolar amino acids. The first one that we have is G, and G stands for glycine, so we can put the one-letter code above. Glycine's R group is so easy that it just glides right on through. It's just one of the easiest ones, so it's literally just a hydrogen. Next, we have Alanine. Alanine's one-letter code is A. Just like A is the first letter of the alphabet and it's easy to remember, Alanine's R group is pretty easy to remember because it's just a methyl group. It's just a simple little CH₃. Also, just like A is the first letter of the alphabet, it's the leader for all of the other letters in the alphabet. We can see that Alanine really acts like a leader to a lot of these other amino acid structures. We can see that already when we go to our next amino acid Valine. Valine's one-letter code is V. What we'll see is that Valine is just Alanine with a V shape. So, there's Alanine with these 2 methyl groups coming off of it. Now the next one is Leucine, and Leucine's one-letter code is L. Leucine is really just a loose extension of Valine. So, the structures here are building off of one another. So, Valine built off of Alanine; it's just a V-shaped Alanine. Leucine's building off of Valine, so Leucine is a loose extension of Valine. So, all you need to do to make it a loose extension is just make the chain a little bit longer by adding a CH₂. Here's Valine here, just a looser extension of it, with an extra CH₂. The next is Isoleucine, and Isoleucine's one-letter code is I. Isoleucine is just an isomer of Leucine, so it has the same number of atoms and types of atoms. They're just arranged in a different way, and the way to remember the arrangement is to remember it's just a lopsided Valine. So, Isoleucine isn't a lopsided Valine. We draw Valine and then t make it lopsided. That is Isoleucine. Now, the next that we have is Methionine, and Methionine's one-letter code is M. Methionine's R group is shaped like an M. So what we could do is just make that M shape. Then, what we know is that at the very end there's going to be a methylthiol group. Methionine, notice that it has "meth" part for the methyl group and "thio" part for the thiol group. It has a methylthiol, and the only way to get the methylthiol is to put the sulfur right here at this position. That is Methionine's R group, and notice it has an M shape, so it goes up, down, up, and kind of right back down. Next is Proline, and Proline's one-letter code is P. Proline's R group looks like the loop of a P. Just like a P, when you draw a P, it has a backbone and then it has a loop. Well, the amino acid backbone kind of goes side-to-side, and then the loop goes like this. Proline's R group is the only one with the loop, so that's how it looks. It also looks like a pentagon because, again, it's going to loop back like this. All that we're seeing here is that they're all CH₂. We're going to have a CH₂ here, we're going to have a CH₂ here, a CH₂ here, and then it connects back to that nitrogen. Notice the number of hydrogens on the amino group is one less than all of the other amino acids. It says NH₂ here instead of NH₃, like all of the other amino acids, because the R group loops back up and connects to the amino group. Let's move on to the aromatic amino acids. There are three amino acids in the aromatic group: Phenylalanine, Tyrosine, and Tryptophan. Our mnemonic is just fat young whippersnappers. For Phenylalanine, its one-letter code is F. Phenylalanine is trying to tell you what its R group is. It's literally Alanine with a phenyl group. So, if we draw an Alanine, remember Alanine up here is just a CH₃. We draw in our Alanine, know the number of hydrogens are going to change, it's going to end up being just 2. But if we draw an Alanine with a branching phenyl group, and remember a phenyl group is just a benzene ring, there we go. That's Phenylalanine's structure. Next we have Tyrosine, and Tyrosine's one-letter code is Y. Basically, Tyrosine is feeding off of Phenylalanine. So, the same pattern here where we see things kind of feed backwards, the structures are feeding backwards. Tyrosine is feeding off of Phenylalanine. Really all we need to do to draw a Tyrosine structure is redraw Phenylalanine exactly. So we can draw our CH₂, draw in our Phenyl group. There's Phenylalanine, and then Tyrosine is having a hydroxyl group baby, so it's basically just an OH group coming off the bottom, and that's Tyrosine's R group. The last one for the aromatic amino acids is W, and W is for Tryptophan. Let me put a W up here. Tryptophan's R group tries to trip you up, but we have these great memory tools. Tryptophan is just Alanine with 2 joined rings. We know the 2 joined rings, there's a 5-membered ring and a 6-membered ring, and the 6-membered ring is the benzene, but the benzene goes at the bottom, so we're going to draw it last. Tryptophan is just Alanine with 2 joined rings, so let's draw Alanine. Alanine again is CH₃, but we know the number of hydrogens are going to change, and it's going to end up being just 2. Then we need to draw our 5-membered ring. There's our 5-membered ring. The next step is to figure out where does the nitrogen go because we know that Tryptophan has a nitrogen atom in it. To remember where the nitrogen goes, you just remember Tryptophan trips on a tripod. What that helps you remember, because a tripod has 3 legs, that helps you remember that there's going to be a 3-carbon start before you actually get to the nitrogen. We count out our carbons; here's 1, here's 2, here's 3; that means our nitrogen must go at this position here. Let's go back and erase these dots, put our nitrogen in here, and then, once we have our nitrogen in, it's figuring out where does the benzene go. We have to remember that the benzene group or the nitrogen is not part of the benzene group, and the benzene has to be below. So because the benzene has to be below, it can't be on either of these two sides. It can't be joined to the ring on either of those two sides, and it can't be on either of these two sides because the nitrogen would be part of the benzene, and the nitrogen cannot be part of the benzene. So then, it has to be that side there. So now we just draw in our benzene, and there's our benzene. Perfect. The very last step is to draw in our double bond, and our double bond does not touch the nitrogen or the benzene, so the only place it can go is here. Then, of course, you fill in the hydrogens at the very end, and that is the structure of Tryptophan. Now let's move on to our polar amino acids, and there are 5 polar amino acids, and the mnemonic to remember them is Santa's team crafts new quilts. The polar amino acids, you think about the North Pole, of course Santa's there, you think of Santa's team. Here we have S, Serine, and Serine just, like alcohol is a serious threat, has an alcohol group. All Serine is is, of course, our leader Alanine coming back into play. Notice that Alanine is the leader for the aromatic groups here, starting the aromatic. Now we see Alanine as the leader for the polar amino acids. Here's Serine and, of course, it's going to be building off of our leader Alanine. So it's going to be Alanine, it's going to be a CH. We know the number of hydrogens are going to change, it's going to end up being 2. Even though Santa and his team know alcohol is a serious threat, Serine and Threonine are going to have alcohols in them, they know that they can have it in moderation while they're crafting these new quilts. We can put Alanine here with an alcohol group. That's all Serine is, is Alanine with an alcohol. Then Threonine is really just building off of Serine's groups. Threonine is T, and what we're seeing is that it's building off of Serine's group. So really, all we need to do to draw Threonine is kind of redraw Serine here. Then all Threonine has is an extra methyl group, it just has an extra methyl group. So if we put in a CH₃ over here, then there's only going to be 1 hydrogen. What you can see this is Threonine's R group. Another way to remember Threonine, so its one-letter code is T, another way to remember Threonine is to remember that it has 3 parts on its only carbon. So its only carbon which is here in the center, has 3 parts: a hydrogen, alcohol group, and a methyl group. Crafting, hammer here, which spends a lot of quiet time in the Sistine Chapel, which is a church. Anytime somebody makes a noise, Cysteine is always like shh. You can remember that Cysteine is really just going to be Alanine with the SH group. It's going to use our leader Alanine again. So Alanine, remember CH, we know that the number of hydrogens are going to change, it's going to end up being 2, and it's just Alanine with a group or an SH group, a sulfhydryl group, that's it. That's Cysteine's R group. The next is Asparagine, and Asparagine's one-letter code is N. The N can help remind you guys of the amide group. Just like an N has these 2 parallel lines here, that can help remind you of the double bond in the amide group. So Asparagine is just going to be our leader Alanine again, of course. So it's going to be Alanine, which of course is just CH. We know the number of hydrogens are going to change, it's going to end up being 2. And then it's going to be our amide group, so it's going to be our C double bond O and our NH₂, and that's it. That is Asparagine's structure. So you can see we have our amide group, it's Alanine with an amide group. Our next and last polar amino acid is Glutamine, and Glutamine's one-letter code is Q, as you can see here. With Glutamine, it's got that GLUT in it, so it's going to be building off of Asparagine's structure. When you have the GLUT, you're going to have the extra butt section or the extra CH₂ group. All you have to do to draw Glutamine is to draw an extra CH₂ and you'll have Glutamine's structure. Let's go ahead and draw it in our CH₂. We know it's going to have an extra CH₂ and then we just draw in our amide. That is it. So you can see we've got our amide here and we've just got an extra CH₂. Glutamine's structure is just that right there. Now we're finally into our final and last group, the charged amino acids. The mnemonic is dragons eat, knights riding horses. Remember that the dragons eating things are negative. There's really nothing positive about a dragon trying to eat you. Dragons eating is negative, these are the negative amino acids. D and E stand for Aspartic acid and Glutamic acid. Those are the acidic ones. Dragons, they shoot out fire and acid out of their mouth, so these are the acidic amino acids. Whereas knights riding horses, which stands for Lysine, Arginine, and Histidine, are the positively charged amino acids because riding a horse is very noble, very positive. They're coming to save the day and fight the dragon, so it's very positive. Knights do not spit acid out of their mouths, so they are not acidic, they're going to be basic. For our negatively charged acetic amino acids, the first that we have is D, and D is Aspartic acid, so we can put in a D over here. Aspartic acid is really going to use our leader again all over. Notice that our leader Alanine, which is up here, was used as a leader for Phenylalanine for Serine, and it's going to be used as a leader again down here for our Aspartic acid. All Aspartic acid is Alanine, so we will draw in our CH. We know the number of hydrogens are going to change, so it's just going to be 2. With Aspartic acid, it's going to have a carboxylic acid, so it'll have a C double bond O. Remember that the carboxylic acid is acidic and it can donate a hydrogen, and when it does that, it becomes Aspartate. Let's draw Aspartate here, which has a negative charge on it. You can see we've got our carboxylate group, which is here, and it's just Alanine with a carboxylate group and that's it. That's the structure of Aspartic acid or Aspartate. The next that we have is Glutamic acid. Again, Glutamic acid, one-letter code is just E. Notice that Glutamic acid is really just building off the structure of Aspartic acid because it's got that GLUT in it, and the GLUT means that it has an extra CH₂. It has an extra butt section. All we need to do to draw Glutamic acid's structure is to draw an extra CH₂. Here's our CH₂, we know it's going to have an extra one, and then we draw in our carboxylate group. That is Glutamate's structure, so remember, Glutamic acid when it loses its hydrogen becomes Glutamate. Here's our Glutamate structure and it has a carboxylate group and the extra CH₂. So, notice it has just one extra CH₂ in comparison to Aspartic acid. That's it for the negatively charged acetic amino acids. Then we move on to our positively charged basic amino acids, and we have t

Fill-in the missing R-groups for the following peptide from memory: D-I-F-C-R-Q.

So this practice problem wants us to fill in the missing R groups for the following peptide from memory, and the peptide is D I F C R Q. Each of these letters is the one-letter symbol for the corresponding amino acids. To solve this problem, we're going to need to remember our mnemonics for memorizing the amino acids, which are GAV LIMP, fat young whipper snappers or FYW, Santa's team crafts new quilts, and dragons eat knights riding horses. The first one that we have is D, which falls under the "dragons eat knights riding horses". "Dragons eat" is shaded green because these are the negatively charged acidic amino acids. Recall that each of these first letters in the mnemonics, they all use alanine as a starter. So, aspartic acid or D is going to use alanine, and we know the number of hydrogens is going to change, it's going to end up being 2. Aspartic acid is an acid because of the presence of carboxylic acids. Aspartic acid can donate a hydrogen and become aspartate, so let's draw aspartate here, the charged one. Aspartate is going to have a carboxyl group branching off the alanine, so it's just alanine with a carboxyl group, and that's it. That is the structure of aspartic acid. The next we have is I for isoleucine, which is found up here. Remember that isoleucine is an isomer of leucine, and remember isomers have the same atoms and types of atoms but a different arrangement of those atoms. The arrangement actually comes from valine, so isoleucine is just a lopsided valine. For our second amino acid up here, we draw in valine. Here's our valine, upside down, and then we just need to make it lopsided. Perfect. That's isoleucine. Now, isoleucine is done. We proceed to F which stands for phenylalanine. Here we have phenylalanine and remember phenylalanine's name is literally telling you what its R group is. It's alanine with a phenyl group. So we draw alanine, changing the hydrogens to end up being 2, and it's okay, it's alanine with a phenyl group and a phenyl group is just a branching benzene ring. That's phenylalanine. Next is C, standing for cysteine, which is found right here. Cysteine sounds like the Sistine Chapel. Sistine spends a lot of quiet time in the Sistine Chapel, which is a church. Anytime somebody makes a noise, cysteine is always like "shh". Cysteine is just alanine with an SH group or a sulfhydryl group. All we do is put in alanine, and the hydrogens are going to end up changing, it's going to end up being 2. It's alanine with an SH group, and the SH group is a sulfhydryl found right here. Then we have R, and R stands for arginine. Arginine, remember, has a mixture of both lysine and histidine. It has parts of the knight's sword and the horse. With an R, think of how many pointy ends there could be to poke someone with, and we know there are 1, 2, 3. That tells us there's a 3 carbon start to our chain. So we draw CH2 CH2 CH2. There's our 3 carbon start, and just like there are 3 pointy ends in our carbon, there must be a triangular nitrogen structure. It's N, C, and N; the C is double bonded to another nitrogen. At this point, all you need to do is fill in the hydrogens. This one's going to have 1, this one will have 2, this one will also have 2, and it's this nitrogen here that's double-bonded that's going to have a positive charge. That's the structure of arginine. Last, now that we have arginine, is Q, which stands for glutamine. Glutamine has that "GLUT" in it, and so glutamine is found over here. Glutamine structure, remember, branches off of asparagine structure. It's literally just asparagine with an extra CH2. All we need to draw its structure is to put in an extra CH2, and then draw an amide (C double bond O with the NH2 on it). That completes the glutamine structure, and this completes this practice problem.

Which of the 20 standard amino acids can be grouped into the following categories?

a. Contain cyclic/ring structures.                                                     b. Sulfur-containing.

So this practice problem asks, which of the 20 standard amino acids can be grouped into the following categories? The first category is containing a cyclic ring structure, and the second category is sulfur-containing. And so, whenever you're considering the 20 amino acids, you should think about the mnemonics that we have. And so those are "Gav limp, fat young whippersnappers" or "FYW, Santa's Team Crafts New Quilts," and "Dragons Eat Nights Riding Horses." And so, we're considering all 20 of these and, first, we're going to work with our first group, so contains cyclic or ring structures. And when you think about cyclic ring structures, you should automatically think about the aromatic amino acids because they all have those benzene rings, which are cyclic structures. And so for the aromatic amino acids, remember that it's just FYW, fat young whippersnappers. So we'll put all three of these over here under this category. So phenylalanine, tyrosine, and tryptophan all have cyclic ring structures. In addition to that, though, we need to check some of the other groups just to make sure that there are no other ring structures. And when we go through, what you'll notice is that P, so P up here for proline, remember has a ring structure. It actually has a cyclic R group. And so remember that it's got a backbone and its R group does a loop and it connects back up to the amino group. And so, proline is going to be included in this group as well. And in addition to that, down here, what we have is histidine. And you can't forget that histidine is alanine with a 5-membered ring. So, histidine also has a ring, so we can add histidine into this group as well. And, these are the five amino acids that have cyclic ring structures. So, that answers part a. Now, for part b, it says sulfur-containing and it turns out there are only two amino acids that fall into this group, and these are methionine and cysteine. So remember that methionine has that "thio" in it. So that "thio" is referring to the thiol group or the, the sulfur that's in its R group. And so methionine has a sulfur atom. And then cysteine, remember, is, spends quiet time in the cysteine chapel, so, it has an SH group, an SH group. And so, both methionine and cysteine can be categorized into this group, so methionine as well as cysteine. And these are the only two amino acids that are sulfur-containing. So this concludes this practice problem, and I'll see you guys in our next video.

Fill-in the blanks & R-groups for each of the α-amino acids from memory.

Hey guys. In this video, we're going to utilize and compile all of the memory tools for memorizing the 20 alpha amino acids into one single video. And so it's going to be a pretty long video, so feel free to fast forward to any portion that's going to help you guys out the most. Now for those of you that have already memorized the 20 alpha amino acids, then that is great news. And if you're short on time, then feel free to skip this entire video since all of the information is a review from our previous lesson videos and there's no new information. But, if you're struggling to memorize these 20 alpha amino acids, even just a little bit, then this video is going to be super helpful for you guys, especially since the memory tools will not only help you in your current biochemistry course, but they will also help you moving forward as you transition into perhaps medical school or graduate school or really any professional field that might expect you to memorize these 20 alpha amino acids. Now guys, trust me on this one. I've tried looking and you won't find another video like this one outside of Clutch Prep that utilizes all of these memory tools to memorize these 20 alpha amino acids. So take advantage. Watch this video as many times as you need to in order to get a good grasp on these memory tools and to memorize these 20 alpha amino acids. Now that being said, you'll get the most value out of this video after you first attempt to fill out all of the blanks and the R groups on this page for each amino acid, from memory yourself before you first watch this video. So, you can use this video to fill in the remaining blanks and the remaining R groups after you've first given it a try yourself. And so we're first going to start off by remembering the mnemonics that help us, group these 20 alpha amino acids into 4 different groups. And so after we do that, then we're going to identify phonetic three-letter codes in each group, phonetic one-letter codes in each group, and then fill out the remaining amino acid codes. And then we'll fill in the R groups, utilizing memory tools for all of the amino acids in each group. Then at the very end, we're going to utilize memory tools to identify the essential amino acids. And so, we'll start off with our nonpolar amino acids which are our hydrophobic or water-fearing amino acids. And you can think about my buddy Gavin, who goes by Gav, and so he recently hurt his leg and so he's not able to run. He has to limp around everywhere. And he's been afraid of water ever since he was 2 or 3 years old, so he's very hydrophobic. And so whenever he's sitting on the beach and a huge wave comes his way, he always gets up really quickly, grabs his crutches, and he limps away as fast as he can. And so you think about our mnemonic GAV LIMP, where each of these letters represents a one-letter amino acid code for the 7 nonpolar amino acids. Now for the aromatic amino acids, you think about the aromatic benzene ring. And so you think about our fat, young whippersnappers. Now for the polar amino acids, you think about the North Pole. And of course, we know that Santa Claus is in the North Pole, so you think about Santa's team crafting new quilts every year for Christmas. And then for our charged amino acids, you think about our mnemonic, dragons eat knights riding horses. And so those are the 4 mnemonics that help us, remember the 4 groups that those amino acids fall into. And so going back up to our nonpolar hydrophobic amino acid group, we're going to identify any phonetic three-letter codes, and the mnemonic that helps us memorize the 4 phonetic three-letter codes is just asparagus or asparagine, chillin' on 3 tropical islands. And so recall that the 3 is only here to help us remember that this mnemonic is specific to the three-letter amino acid codes. And so ASN is for asparagine, GLN is for glutamine, TRP is for tryptophan, and ILE is for isoleucine. And so what do you guys think? Looking at this nonpolar amino acid group, are there any amino acids that have a phonetic three-letter code? Yes. That's right. So taking a look at isoleucine here, ILE, notice that it is part of our nonpolar group because the I here is for isoleucine. And so what we can do is we can put isoleucine's 3-letter code over here. Now notice that none of the other amino acids in this group have a phonetic three-letter code. So that means that their phonetic three-letter code is going to be super easy because it's literally just the first three letters of the amino acid itself. And so g is for glycine, so it's going to be g l y. A is for alanine, a l a. V is for valine, v a l. L is for leucine, which is l e u. M is for methionine, m e t. And p is for proline, which is p r o. Now, moving on to our phonetic one-letter codes, recall the mnemonic that helps us memorize those is just nerdy, Waldo, qualifies, and Fortnite. And so are there any, looking at this nonpolar amino acid group, what do you guys think? Are there any that have a one-letter code of phonetic origin? No, that's right. So notice that none of these in the nonpolar amino acid group have a phonetic one-letter code, which means that its one-letter code is going to be super easy because it's literally just the first letter of the amino acid itself or k for lysine. But lysine is not part of this group so it's literally just going to be the first letter of the amino acid itself. So for glycine, it'll be g. For alanine, a. Valine, v. Leucine, l. Isoleucine, I. Methionine, m, and proline, p. Alright. So now we can move on to our next group, the aromatic amino acids. And so what do you guys think? Are there any of these aromatic amino acids that have a phonetic three-letter code? Yes. That's right. So recall that tryptophan so if we go back up to our phonetic three-letter code, recall that tryptophan does have a phonetic three-letter code and tryptophan is the w in our mnemonic. And so what we can do is we can put tryptophan's 3-letter code over here. Now for the others, they do not have phonetic three-letter codes, so it's literally just going to be the first three letters of the amino acid itself. So for phenylalanine, it'll be p h e, which is the f here. For tyrosine, it'll be t y r. Alright. So how about the phonetic one-letter codes? Are there any phonetic one-letter codes in this aromatic amino acid group? Yes. That's right. All 3 of them have phonetic, one-letter amino acid codes. So the f here is going to be for phenylalanine, the y is for tyrosine, and the w is for tryptophan. And so all of those fall into our nerdy WQF mnemonic. Now, moving on to the polar amino acids down below, are there any that have a phonetic three-letter code of origin? Yes. That's right. So take a look at asparagine and glutamine. And so asparagine and glutamine, if we go back up to our three-letter code, so asparagine and glutamine are both part of the polar amino acid group. And so down below, we can go ahead and indicate that they have phonetic three-letter codes. And so a spare gene is going to be, this one over here, and glutamine will be over here. So how about for phonetic one-letter codes? Are there any in the polar amino acid group that have phonetic one-letter codes? What do you guys think? That's right. So notice that, both asparagine and glutamine also have phonetic one-letter codes, and so, we can go ahead and place those in here as well. And so that means that all of the other amino acids, for the three-letter codes, it's literally just going to be the first three letters of the amino acid itself. And so for serine, it's going to be s e r. For threonine, it's going to be t h r. For cysteine, it'll be c y s. And then for the one-letter codes, because these are not of phonetic origin, it's literally just going to be the first letter of the amino acid itself. So for serine, it'll be s, for threonine, it'll be t, and for cysteine, it'll be c. Alright. So pretty easy so far. Right? So now moving on to the charged amino acids, what do you guys think? Are there any of, the charged amino acids that have phonetic three-letter codes? No. That's right. So none of these have phonetic three-letter codes, which means that their three-letter codes is literally just going to be the first three letters of the amino acid itself. And so for aspartic acid or, aspartate, it'll be a s p. For glutamic acid, it'll be glu. For lysine, it's going to be l y s. For arginine, it'll be a r g. And for histamine, it'll be h I s. Now, are there any of these that have a phonetic one-letter code? What do you guys think? Well, that's right. So notice that aspartic acid has a one-letter code, of phonetic origin, so we can put that in. So does glutamic acid, and, so does lysine and arginine. And so, lysine is k and arginine is r. And histidine is the only one that does not have a phonetic one-letter code in the charged amino acid group. And so it's literally just going to be the first letter of its, of the amino acid itself. And so now we filled in all of the abbreviations for all 20 of the alpha amino acids. So now what we're going to do is go back up and we're going to fill in the R groups for each of these amino acids. Now recall that glycine's r group is so easy. It literally just glides right on through, and so that's because it's a hydrogen atom. It's the smallest, R group of them all and the easiest to remember. Now alanine, because a is the first letter of the alphabet and that's easy to remember, alanine's R group is also pretty easy to remember because it's literally just a methyl group or a CH three group. And so, just like alanine is or just like a is the first letter of the alphabet and it's the leader for all of the other letters of the alphabet, alanine pretty much acts like a leader amino acid for a lot of the amino acids, and we'll be able to see that moving forward in this video. Now, next what we have is valine, and already valine is going to be using alanine as its, it's going to be using alanine as a leader. So essentially what you're going to see is these arrows that go back, show how these amino acid structures feed off of the ones that are neighboring. And so valine is literally just alanine with a v shape. So it's going to be a CH 2 here or a CH, and it's going to have a v shape, so 2 methyl groups coming off, and that is valine structure. Now, leucine, which is next, is literally just going to be a loose extension of valine. So leucine's structure is feeding off of valine structure. And so, again, it's going to be a loose extension of valine, so it's literally just going to have a CH 2 and then it's going to have a c h, and then it will have the v shape. And so by loose extension, we just mean that it has an extra c h 2 in here in comparison to this valine. Now, isoleucine, which is the next one, is really an isomer of Leucine. So it has the same exact chemical formula but it, arranged in a different format. And so isoleucine structure really branches off of valine structure. And so isoleucine is really just a lopsided valine. And so, by a lopsided valine, all we need to do is draw a valine, and then we need to make it lopsided. And so that is isoleucine structure. Now for methionine, its r group looks like an m. It's one-letter code. And so literally, it goes down, it goes back up, and then it goes back down, and you can see that it's got this m-looking shape to it. But because methionine has the meth, has the meth in it, so it stands for a methyl thiol, so it has a methyl group and a thiol group, we know that that has to go at the very end of the molecule. And so essentially what we're going to have is the same m here, but at the very end, there's going to be a sulfur atom and a, methyl group coming off of it. And so that is methionine structure, looks a little bit like an m. Now for proline structure, you can think of this p here really does look like a proline structure. So you can think the backbone of the p, just like the backbone of the amino acid, is going to be going across like this. And the loop of the p here is really like the R group of proline. So it's like a flipped p. And you can also think proline pentagon. And so, literally, what you'll see is that it's going to make a pentagon shape that loops back up. And so this pentagon is just made up of a bunch of, methylene groups or a bunch of c h two groups. So essentially, it's going to have a c h two here. It'll have another c h two over here, another c h two here, and then it'll link back to the original nitrogen. And so notice that it has an n h two on its amino group rather than an NH 3 like all of the other amino acids, and again, that's because it has a cyclic r group. And so that is it for all of the nonpolar amino acids, and so we can move on to the aromatic amino acids. Now for the aromatic amino acids, we're starting off with f which is for phenylalanine. And phenylalanine is literally trying to tell you what its r group is. It's literally just alanine with a fetal group. And so if we go back up a little bit, we can see that alanine is a leader amino acid. So it's going to lead for the 1st amino acid that is part of the aromatic amino acid group. And so, alanine is a CH 3, so we know that the number of hydrogens are going to change. It's going to end up being 2, and so it's going to be alanine with a phenyl group or a branching benzene ring coming off of it. And so that is it, that is phenylalanine structure and that is it for phenylalanine. Now, tyrosine is feeding directly off of phenylalanine structure. So, essentially what we have here is that Tyrosine is phenylalanine with a hydroxyl group baby coming off the bottom. And again, the baby is going to be coming off of the bottom of the benzene ring, not the side or the top or anything crazy like that. It's going to be coming off the bottom. And so all we need to do is draw phenylalanine exactly, so there is phenylalanine. And then for tyrosine, we need to draw a hydroxyl group baby coming off the bottom, And that is it for tyrosine structure. Now for tryptophan, it's really going to try to trip up you up because it's our group is pretty complicated, but we have good memory tools that's going to help us remember this. And so tryptophan is literally just alanine with 2 joined rings branching off. The first is a 5-membered ring and the second is a benzene ring that's going to go below the structure. And because it goes below, we're going to draw that 6-membered ring last. So we can go ahead and draw an alanine, so it's going to be CH, and we know that the number of hydrogens are going to change to, And then it's going to have a 5-membered ring coming off of it. So there's the 5-membered ring. And again, we're going to draw the 6-membered ring, the benzene ring, last since it goes below the structure. So next, what we need to do is determine where this nitrogen atom goes. And so what can help us remember where the nitrogen atom goes is that, tryptophan trips on a tripod, and a tripod has 3 legs on it so that can help us remember that there's a 3 carbon start before you actually get to the nitrogen. And so that means that we here's 1 carbon, here's 2 carbons, here's 3 carbons, and our nitrogen can go right at this position over here. And so we can go ahead and get rid of these dots here and put our nitrogen at this position. And then, of course, what we're going to do is draw in our benzene ring. Now our benzene ring has to go below. So we know that it can't go on this side. It can't be joined to the ring on this side because it would be above. It can't be joined to the ring on this side because it would be above. And, also, the benzene ring does not include the nitrogen. So the nitrogen is not part of the benzene. And so that means that the benzene ring can't be joined on this side, and it can't be joined on this side. And this is the only side that the benzene ring can be joined to. So that means that here we can put our benzene ring. And, essentially, all we need to do is fill in the double bond, and the double bond does not touch the benzene ring or the nitrogen atom. So the only place that that double bond can go is, right at this position here. And so, of course, we gotta fill in our hydrogen atoms and that is it for tryptophan structure. And so now, we can move on to our next amino acids which are the polar amino acids. And, of course, the first amino acid that we have is serine. And, again, serine's

Match the amino acid to the type of R-group it has:

Leu ____                                   1. Hydroxyl-containing

E ____                                      2. Acidic

K ____                                      3. Basic

Ser ____                                  4. Sulfur-containing

C ____                                     5. Nonpolar aromatic

W ____                                    6. Nonpolar aliphatic

So this practice problem wants us to match the amino acid to the type of R group that it has. And the first amino acid listed is leu, which is leucine, and leucine's one letter code is 'L'. Recall that the way we memorize all the amino acids is by memorizing those mnemonics, and the mnemonics are Gav Limp, Fat Young Whippersnappers, Santa's Team Crafts New Quilts, and Dragons Eat Nights Riding horses. 'L', as you can see, falls here at this position. Remember that 'L' is leucine, which is just a loose extension of valine. When you look at our R group here, it's not hydroxyl containing, it's not acidic, basic, it doesn't have a sulfur. It is nonpolar, but it's not aromatic or it would be a 'Fat Young Whippersnapper'. That means that '6' must be the only choice, non-polar and aliphatic, and that is Leucine's R group. So we can go ahead and put a '6' here. Now our next one is 'E' and 'E' stands for glutamic acid, which is found here. Glutamic acid falls into the negatively charged acidic group, and it doesn't have a hydroxyl group, it's not sulfur containing, it's not aromatic, so the only group that glutamic acid falls under is the acidic group here. So, we can put here for 'E', glutamic acid, a number '2' and cross that off. Then, 'K' here, remember, stands for lysine and lysine is found here at this position, which means that it is a positively charged basic amino acid. Just like we did before, it doesn't have a hydroxyl group, it's not sulfur containing, it's not aromatic, so that means that lysine must be basic and so we can put a '3' here for that and cross it off. The next one is 'SER' and 'SER' stands for serine and serine's one letter code is just an 'S'. When we go and look at serine over here, notice that serine is using alanine as a leader and it's going to have an alcohol group, so it's just alanine with an alcohol. Because it has an alcohol, it's going to be hydroxyl containing. That means that our next one here, serine, is just going to be a '1', and we can cross this off. Then, what we have next is 'C', and 'C' stands for cysteine, and cysteine is found right here at this position here. Cysteine, remember, spends time in the Sistine chapel or church, and whenever someone makes a noise, cysteine says 'sh'. So cysteine is really just alanine with an SH group or a sulfur containing group. And, 'W' is tryptophan and tryptophan falls under the Fat Young Whippersnappers group, which is our aromatic group. And of course, that means that 'W' or tryptophan must be non-polar and aromatic, so we can go ahead and cross that off. This concludes this practice problem and I'll see you guys in our next one.

Name the amino acids that contain each of the following in their R-groups:

a) Hydroxyl group: __________________                      e) Sulfur atom: ­­­­­­­__________________

b) 2^nd chiral carbon: __________________                    f) Amino group: __________________

c) Amide group: __________________                          g) Acidic group: __________________

d) Basic group: __________________                           h) Aromatic ring: __________________

So this practice problem wants us to name the amino acids that contain each of the following in their R groups. And so the first one listed is a hydroxyl group. And remember that the way we memorize the amino acids is by these mnemonics Gav Limp, Fat Young Whippersnappers, Santa's team crafts new quilts, and dragons eat knights riding horses. And so for the hydroxyl group, basically, the strategy is to go through the amino acids and determine which one has a hydroxyl group. And so for the first seven, what you'll realize is that they do not have a hydroxyl group. But once we get to our second category, phenylalanine does not, but tyrosine does because tyrosine, which is Y here, is basically phenylalanine with a hydroxyl group. So we can go ahead and add tyrosine or Y to our list. Now the next two are serine and threonine. So tryptophan doesn't have one, but the next two in our next group are serine and threonine, which remember, even though "alco" is a serious threat, so "serious" for serine and "threat" for threonine, that, they do have alcohols in them or hydroxyl groups. And so serine and threonine, we can add to our list here, so serine and threonine. And so none of the other ones actually have just hydroxyl groups. Now for b, it says a second chiral carbon. Now we know that all the amino acids except glycine, of course, are chiral. Glycine is the only one that is achiral, and so all of them have at least one chiral carbon, which is the alpha carbon. But there are some that actually have a second chiral carbon in their R group, and really the only way to be able to figure this out is to draw and look for it. And so when you look through these amino acids, you'll realize that isoleucine, so this one here, when you draw its R group, so remember, isoleucine is an isomer of leucine and it, is basically a lopsided valine, so we can draw valine and make it lopsided. So this carbon here in the middle, this carbon, and this carbon are both chiral. So isoleucine is one, so we get rid of this R group really quick and add isoleucine in there. So isoleucine has one, second chiral carbon and so does threonine. So threonine has three parts on its only carbon. So if we draw its only carbon, which is C, it has three parts, a hydrogen, a methyl group, and a hydroxyl group. And so this carbon, as well as this carbon, are chiral. So threonine is the other one, so we can add that one in as well. And so we'll add that in. So those are the only two with a second chiral carbon. Now for an amide group, recall that the asparagine, so asparagine, which is here, and glutamine, which is Q here, they both have amide groups. So we can add those to our list. So asparagine and glutamine. And then for the basic group, that's an easy one because we memorized our mnemonic like that. So remember, knights riding horses, which is right here, down here, it's K, R, and H. These three are the positively charged, so they're positively charged basic amino acids. So, knights riding horses or K R H, which is lysine, arginine, and histidine, are the three basic amino acids. Now for e sulfur atom, we had a previous practice problem that highlighted this and there are only two amino acids with sulfur atoms, and those are, of course, methionine, which is here, and cysteine, which is here. So methionine has a methyl thiol, so it has that sulfur. And then cysteine, of course, has the SH group or the sulfhydryl group. Those are the only two with sulfur atoms. For amino groups, there are only three that actually have just an amino group, and those three are, of course, our basic amino acids. So it's lysine, arginine, and histidine. And then for the acidic groups, we know that it's going to be our two acidic amino acids. So our dragons eating our negatively charged acidic amino acids because dragons spit acid out of their mouths, so these are negatively charged and acidic, so of course, it's going to be aspartic acid and glutamic acid. And then for our aromatic rings, we know that's going to be pretty easy too because this is just going to be our aromatic amino acids here. So fat young whippersnappers, so F Y W. And so this concludes this practice problem, and I'll see you guys in our next video.

Here’s what students ask on this topic:

What are some effective mnemonics for memorizing amino acids?

Mnemonics are a great way to memorize amino acids. For non-polar amino acids, use GAVLYMP: Glycine (G), Alanine (A), Valine (V), Leucine (L), Isoleucine (I), Methionine (M), and Proline (P). For aromatic amino acids, remember 'fat young whippersnappers': Phenylalanine (F), Tyrosine (Y), and Tryptophan (W). For polar amino acids, use 'Santa's team crafts new quilts': Serine (S), Threonine (T), Cysteine (C), Asparagine (N), and Glutamine (Q). Lastly, for charged amino acids, 'dragons eat, knights riding horses' helps recall Aspartic acid (D), Glutamic acid (E), Lysine (K), Arginine (R), and Histidine (H).

How can I remember the structures of non-polar amino acids?

To remember the structures of non-polar amino acids, use the mnemonic GAVLYMP. Glycine (G) has a simple hydrogen R group. Alanine (A) has a methyl group (CH₃). Valine (V) is alanine with a V-shaped extension. Leucine (L) is a loose extension of valine with an extra CH₂. Isoleucine (I) is an isomer of leucine, resembling a lopsided valine. Methionine (M) has a methylthiol group, forming an M shape. Proline (P) has a unique loop structure, resembling a pentagon.

What are the one-letter codes for aromatic amino acids?

The one-letter codes for aromatic amino acids are: Phenylalanine (F), Tyrosine (Y), and Tryptophan (W). These amino acids can be remembered using the mnemonic 'fat young whippersnappers'.

How do I differentiate between polar and non-polar amino acids?

Polar amino acids have side chains that can form hydrogen bonds, making them hydrophilic. Use the mnemonic 'Santa's team crafts new quilts' for polar amino acids: Serine (S), Threonine (T), Cysteine (C), Asparagine (N), and Glutamine (Q). Non-polar amino acids have hydrophobic side chains. Use GAVLYMP for non-polar amino acids: Glycine (G), Alanine (A), Valine (V), Leucine (L), Isoleucine (I), Methionine (M), and Proline (P).

What mnemonic can help me remember charged amino acids?

To remember charged amino acids, use the mnemonic 'dragons eat, knights riding horses'. Dragons (D and E) represent the negatively charged acidic amino acids: Aspartic acid (D) and Glutamic acid (E). Knights riding horses (K, R, and H) represent the positively charged basic amino acids: Lysine (K), Arginine (R), and Histidine (H).