Amino Acid One Letter Code: Study with Video Lessons, Practice Problems & Examples

Understanding the one-letter codes for amino acids is essential for protein analysis. Eight amino acids have phonetic one-letter codes, making them crucial to memorize: Arginine (R), Asparagine (N), Aspartic acid (D), Glutamic acid (E), Glutamine (Q), Phenylalanine (F), Tryptophan (W), and Tyrosine (Y). The remaining amino acids use their first letters as codes, except for Lysine, which is K. This systematic approach simplifies amino acid identification, aiding in studies of protein structure and function.

Phonetic 1-letter Amino Acid Abbreviations

In this video, we're going to begin our discussion on the amino acid one-letter codes for all 20 of the standard amino acids. So it turns out that the one-letter amino acid codes are just a little bit more challenging to memorize than the three-letter amino acid codes. But that just has to do with the fact that there are more one-letter abbreviations of phonetic origin. And so, recall with our previous lessons on the three-letter amino acid codes, that there were only 4 amino acids with phonetic three-letter abbreviations. But with our one-letter amino acid codes, there are actually 8 amino acids with phonetic one-letter abbreviations. So that's double the amount, and that's why they're a little bit more challenging to memorize. But if we're able to commit all 8 of these one-letter abbreviations of phonetic origin to memory, then memorizing all of the other one-letter abbreviations is going to be super, super easy for you guys. And we'll be able to see how that works in our next lesson video. But for now, down below in this box, we have the 8 one-letter symbols of phonetic origin organized in alphabetical order. And so, what you'll see is in the first blank for each of these amino acids, we need to think what letter we could place to fill the sound phonetically and reveal the one-letter code in the second blank. And so for arginine, it's pretty clear that if we put an 'R' into this blank here, we can fill the sound phonetically. And so its name its sound is going to be arginine, and its one-letter code will be 'R'. Now, for asparagine, we have this blank to fill. And so if we put an 'N' into this blank, we can fill the sound phonetically for asparagine, and its one-letter code is 'N'. For aspartic acid, if we put a 'D' here for aspartic, it will reveal its one-letter code of 'D'. Now for glutamic acid, in the glutamic part, if we put an 'E' down here, we can fill the sound phonetically to give it a one-letter symbol with an 'E'. And for glutamine, up at the top here, if we put a 'Q' in here, it'll actually fill the sound phonetically. So it'll say glutamine. And glutamine, glutamine sound very similar. And so, its one-letter code is 'Q'. Now, for Phenylalanine, if we put an 'F' in here into this first blank, we can fill the sound phonetically and give it a one-letter code of 'F'. Now, for tryptophan, we have to think how Bugs Bunny would say tryptophan. And the way that he would say it is Twiptophan with a 'W'. And so if we were to put a 'W' into this blank, it'll fill the sound phonetically and its one-letter code is 'W'. And then, of course, last but not least, tyrosine's one-letter code is going to be 'Y', and we can fill the sound phonetically here with a 'Y'. And so, essentially down below in this image, what we have is a mnemonic to help you guys memorize these 8 amino acids with phonetic one-letter abbreviations. And that mnemonic is just 'nerdy WQF', or 'nerdy Waldo qualifies in Fortnite'. And so, most of you guys know what Fortnite is, but for those of you that don't, Fortnite is a competitive video game. And so, most of you guys have either played Fortnite, know someone that plays Fortnite, or know someone that has played Fortnite. But none of you guys know anybody that's played Fortnite as much as Waldo. And to tell you the truth, that's why it's so hard to find Waldo in the first place because he spends all of his time playing Fortnite up in his room all day and night. And so, with this mnemonic over here, each letter in the word nerdy represents one of the one-letter abbreviations of phonetic origin. And then WQF, of course, represents, tryptophan, glutamine, and phenylalanine, which are also one-letter abbreviations of phonetic origin. And so you can see here, we have this Waldo here, and he's pretty nerdy. He's got these glasses on and he's holding up his number one finger and he's got this sign here, this name tag that says, hello. My name is Waldo. And he's saying I'm nerdy. I qualified in Fortnite. And so by qualified, what he really means is first place, and first place can help us remember that this mnemonic here is for the one-letter amino acid codes, the first place. And that's why he's holding up number one for the one-letter amino acid codes. And so if you guys can remember, 'nerdy WQF' or 'nerdy Waldo qualifies in Fortnite', then you'll be able to remember the 8 amino acids with one-letter abbreviations of phonetic origin. And remember, these are the 8 abbreviations that you really want to spend most of your time committing to memory. Because once you've committed these 8 to memory, then memorizing all of the other amino acids is going to be much, much easier. And we'll be able to see how that works better in our next lesson video. So I'll see you guys in our next video where we'll be able to get some practice with these concepts.

Which of the following amino acid 1-letter symbols is of phonetic origin?

• A. E.
• B. K.
• C. T.
• D. C.

Other Amino Acid 1-Letter Codes

So in our last lesson video, we talked about the 8 one-letter amino acid abbreviations of phonetic origin. And remember, it's these 8 that you really want to spend most of your time studying and memorizing because those are the hard ones to memorize. And once you've committed those 8 to memory, then memorizing all of the other one-letter abbreviations are going to be super easy for you guys as we'll see in this video. And so, what we've done is we've taken all the other one-letter codes and abbreviations and we've broken them up into 3 different groups and color-coded them as you can see here. So in our first group, we have the green group and what you'll see is that this green color here corresponds with the green color that we see throughout our image in our example down below. Now, our next group, what we have is our light blue group and again, this light blue color corresponds with the light blue color throughout our image in our example below. And then our yellow group here corresponds with the yellow amino acid in our image below. And so, what you'll also notice is that over here in pink, what we have are the 8 one-letter amino acid abbreviations of phonetic origin. And we already talked about those in our previous video, so these one-letter abbreviations are already provided for us. And so we're not going to be focusing on these, we're going to be focusing on the ones that we haven't yet talked about, which are the ones that are in blanks throughout our image. And so, in our first group, we have the green group, and what you'll see is that for amino acids with unique first letters, their one-letter code or symbol is literally just their first letter, and this applies to all of the ones that are in green in our example below. So what you'll see is that cysteine over here has a first letter of c, which is a unique first letter amongst all of the other first letters for all the other amino acids. And because it has a unique first letter, its first letter is going to be its one-letter code. And the same applies for histidine, isoleucine, methionine, serine, and valine, all of which have unique first letters and their first letter is used as their one-letter abbreviation. So pretty easy. Right? So in our next group, what we have is the light blue group. And in this group, what we'll realize is that some amino acid first letters are not unique, but the first letters are still used for these amino acids and that's because these amino acids are more commonly found in proteins throughout nature. And so, for example, both leucine and lysine start with the letter l, but overall, leucine is more commonly found in proteins than lysine. And so for that reason, leucine is prioritized with the one-letter symbol of l. And the same applies for all of the amino acids that are shaded in blue in our example below. And so, what you'll see is that alanine over here has a first letter of a, which is not a unique first letter. But alanine's first letter is still used as its one-letter code. And again, that has to do with the fact that alanine is more commonly found in proteins throughout nature, than these other three amino acids that also start with the first letter a. The same applies for glycine. Glycine's first letter is g and it is not a unique first letter, but it's still used as its one-letter code because it's more commonly found. Leucine, we just mentioned above in our example, which is more common than lysine. Proline is more common than phenylalanine, and threonine is more common than tryptophan or tyrosine. And so, at this point, what you'll notice is that we've assigned one-letter abbreviations for 19 out of 20 amino acids. And so far, all we've said is that it's just the 8 of phonetic origin and all the other ones are just the first letter so far, so super easy to remember. Remember. And so the one amino acid that has not been assigned a code yet is lysine, which is this yellow one here and it's found in this group all by itself. And so at this point, only a few letters remained in the alphabet that were not already assigned to an amino acid. And so literally, the letter k was chosen for lysine because it's the one that was closest to l, which is lysine's first letter, that wasn't already taken by another amino acid. And so lysine's one-letter abbreviation is literally just the letter k. And so, again, when you're trying to memorize these one-letter abbreviations, instead of trying to memorize all 20 of them, remember that you want to memorize the ones that are in pink. So all the ones that are in pink here are the ones that have one-letter abbreviations of phonetic origin, and there are only 8 of those. So once you've memorized those 8, all you need to know is that lysine's one-letter code is k and then all the other ones are just the first letter. So, the ones that are in the blue categories and the green categories, there's really no need to try to memorize those because they're literally the first letter of the amino acid itself. So, hopefully that'll help

Which 1-letter-code is unique in that it is neither the first letter of the amino acid nor phonetic in origin?

• A. I.
• B. L.
• C. K.
• D. G.
• E. T.

Convert the following amino acids into their 1-letter codes: Glycine, Isoleucine, Valine, Tryptophan, Proline.

• A. G, I, V, T, P.
• B. L, I, V, Y, P.
• C. G, L, V, W, P.
• D. G, I, V, W, P.

Complete the amino acid abbreviation chart below from memory.

So here's a pretty hefty practice problem that wants us to recall all of the amino acid abbreviations that we've learned thus far. The directions say to complete the amino acid abbreviation chart below, from memory. To keep things in the same order that we learned them, we're first going to fill the chart with the 3-letter amino acid codes in these larger blanks throughout our chart. After we complete the chart with the 3-letter amino acid code, we'll switch over to the 1-letter amino acid code and complete the chart with the smaller blanks throughout our chart. Recall with the 3-letter amino acid codes that there were only 4 amino acids with 3-letter codes of phonetic origin, and those were the 4 that we really wanted to spend most of our time committing to memory because once we memorize those 4, memorizing all the other 3-letter amino acid codes is going to be super easy since they're literally just the first three letters of the amino acid itself. We had a mnemonic to help us memorize the 4 amino acids with phonetic three-letter codes; that mnemonic is "asparagus or asparagine chilling on 3 tropical islands." The "3" here helps us remember that this mnemonic is specifically for the phonetic three-letter codes. From memory, ASN is for asparagine, GLN is for glutamine, TRP is for tryptophan, ILE is for isoleucine. Applying them to our chart, asparagine is ASN. Glutamine is GLN. Isoleucine is ILE. Tryptophan is TRP. Now that we've completed those 4 amino acids with 3-letter codes of phonetic origin, all of the other amino acid three-letter codes are super easy because they're literally just the first three letters of the amino acid itself. For instance, alanine's 3-letter code is Ala, arginine is Arg, aspartic acid is Asp, cysteine is Cys, glutamic acid is Glu, glycine is Gly, histidine is His, leucine is Leu, lysine is Lys, methionine is Met, phenylalanine is Phe, proline is Pro, serine is Ser, threonine is Thr, tyrosine is Tyr, and valine is Val. Most of these amino acids are super easy to memorize, and the only ones we needed to commit to memory are the ones highlighted in blue because they are of phonetic origin. Now that we've completed all of the 3-letter amino acid codes in our chart, we're going to move on to our one-letter amino acid codes. With our one-letter amino acid codes, there were 8 amino acids that had one-letter codes of phonetic origin. These were the ones that we wanted to spend most of our time memorizing because once we committed those 8 to memory, memorizing all the other letter codes was super easy. The mnemonic that helps us memorize the phonetic one-letter codes is "nerdy WQF." If you remember "nerdy WQF," you'll recall the 8 amino acids with one-letter codes of phonetic origin. Specifically, N is for asparagine, E is for glutamic acid, R is for arginine, D is for aspartic acid, Y is for tyrosine, W is for tryptophan, Q is for glutamine, and F is for phenylalanine. Now that we've labeled all of these one-letter codes as phonetic, we know that the remaining one-letter codes are going to be super easy because it's just the first letter of the amino acid or K for lysine. K is the unique amino acid code that is neither phonetic in origin nor the first letter of the amino acid. Other one-letter amino acid codes are just the first letter of the amino acid itself: A for alanine, C for cysteine, G for glycine, H for histidine, I for isoleucine, L for leucine, M for methionine, P for proline, S for serine, T for threonine, and V for valine. By focusing our memory specifically on these phonetic abbreviations down below, we can reduce a lot of our memory load and memorize these amino acid abbreviations much easier. We'll be able to get more practice utilizing all of these abbreviations as we move along through our course and as we tackle our next set of practice problems. See you guys in our next practice video.

Convert the following 3-letter amino acid codes into 1-letter codes to answer the following question:

How does NASA organize a party?

So this practice problem wants us to convert the following 3 letter amino acid codes into their one letter amino acid codes to answer the following question, how does NASA organize a party? And so really this is the first practice problem that's asking us to convert amino acid 3 letter codes directly into amino acid 1 letter codes, which we can provide down below underneath each corresponding dotted line. And so when we're memorizing amino acid abbreviations, we know that we should focus most of our time memorizing the abbreviations of phonetic origin. And so the mnemonic that helps us memorize the phonetic three letter codes is just asparagus or asparagine chilling on 3 tropical islands. And so we know that the 3 here is specifically to help us remember that this mnemonic is for the phonetic three letter codes. By spending a lot of time committing these four three letter abbreviations to memory, we know that ASN is specifically for asparagine, GLN is for glutamine, TRP is for tryptophan, and ILE is for isoleucine. And so, if it's not one of these 4 three letter codes, then we know that the 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 if we go through and scan all of these three letter codes here, notice that there's only one three letter code of phonetic origin, and of course, that is asparagine, ASN. And all of the other three letter codes here are not of phonetic origin. And so that means their first three letters are literally the three letter code. Now for the one letter phonetic code, recall that the mnemonic to help us memorize them is just nerdy WQF. And so we know that this stands for Nerdy Waldo qualifies in Fortnite. And so, by spending a lot of time memorizing these 8 amino acid one letter codes of phonetic origin, we know that an N represents asparagine, E is glutamic acid, R is arginine, D is for aspartic acid, Y is for tyrosine, W is for tryptophan, Q is for glutamine, and F is for phenylalanine. And so what we're going to do is, as we provide the one letter codes down below, we're going to put the one letter codes that are phonetic origin in red. And the ones that are not in phonetic origin, we'll put them in black. And so for our first amino acid here, THR, that is specifically for threonine. And threonine is not, one of these amino acid one letter codes of phonetic origin. And so we can put a T down below because we know it's literally going to be the first letter of the amino acid itself. And the same applies for HIS, which stands for histidine. And so, its first letter here of H, it's going to be its one letter code, because it's not part of our mnemonic here. Now, for glutamic acid, notice that glutamic acid is actually part of our phonetic one letter codes, and that's because glutamic acid is the E here. And so because glutamic acid has a phonetic one letter code, we can put it in red down below with an E. Now, the same applies for TYR, which is for tyrosine. And tyrosine's one letter code is Y, so down below, we can put Y in red. And then, PRO is actually for proline, and proline is not one of these 7 phonetic one letter codes. So it's literally just going to be the first letter, which is P. For leucine, the same exact applies. So LEU is for leucine, and it is not one of our phonetic one letter codes. So its one letter code is literally going to be its first letter, so we can put L here. Same applies for ALA, which is for alanine. It's going to be its first letter because it's not part of our mnemonic for the phonetic one letter codes. Now for asparagine, it actually is. So recall that asparagine's one letter code is an N here. And so, it has a phonetic three letter code, as well as a phonetic one letter code of N. For GLU, we already did previously. So notice the GLU is for glutamic acid, which we already did, and its one letter code is an E. And we'll put that in red, since it is one of our phonetic, one letter codes. And then, of course, threonine, we already did previously as well. And threonine is not one of our phonetic one letter codes, so we can put it down below as the first letter being T. And so, really, that answers our practice problem. And so how does NASA organize a party? Well, they plan it. So that concludes this practice, and I'll see you guys in our next video.

Convert the following 3-letter amino acid codes into 1-letter codes to reveal the sentence.

So this practice problem is really similar to our previous practice problem where it wants us to convert the following 3-letter amino acid codes into the 1-letter amino acid codes in order to reveal the sentence. And so we know that when we're memorizing all of the amino acid abbreviations, we want to spend most of our time memorizing the amino acid abbreviations of phonetic origin. And the mnemonic that helps us memorize the phonetic three-letter codes is just asparagus or asparagine chilling on 3 tropical islands. And so we know that the 3 here helps us remember that this mnemonic is specifically for the phonetic three-letter codes. And by spending a lot of time memorizing these four three-letter codes, we know that ASN is for asparagine, GLN is for glutamine, TRP is for tryptophan, and ILE is for isoleucine. And so looking at our 3-letter codes here, we can highlight all of the ones that have phonetic three-letter codes. And so we know that ile is for isoleucine, and we have ile ILE again here for isoleucine. Then we have ASN for asparagine, and that is it. All other three-letter codes that are provided are not of phonetic origin. And if it's not phonetic origin, if it's not one of these 4, three-letter codes, then we know that the 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 for the one-letter codes of phonetic origin, the mnemonic that helps us memorize those 8 amino acids is just nerdy WQF, which of course stands for nerdy Waldo qualifies in Fortnite. And by spending a lot of time with these one-letter amino acid codes, again, we know that the n is for asparagine, e is for glutamic acid, r is for arginine, d is for aspartic acid, y is for tyrosine, w is for tryptophan, q is for glutamine, and f is for phenylalanine. And so if it's not one of these 8 phonetic one-letter codes, then the one-letter code is going to be really really easy because it's literally just the first letter of the amino acid or k for lysine. And so notice here, in our mnemonic we have lys, which stands for lysine. And because lysine is literally the only amino acid one-letter code that is not either the first letter of the amino acid itself or phonetic in origin, it is actually the one-letter code of k. So we can go ahead and put a k here for this lysine. And so, we can go through each of these, three-letter codes and convert them into the one-letter code. And if it's in, if it's a one-letter code of phonetic origin, we'll color code it in red. And if it's not, then we'll color code it in black. And of course, k here is unique because it's neither the first letter nor is it phonetic in origin. And so for isoleucine, we know that its one-letter code is going to be its first letter just I, and we know that because it's not part of our mnemonic over here for the phonetic one-letter codes. So down below, we can put an I, and that will apply for this isoleucine as well over here. And, it also applies for LU, which is for leucine, and leucine is not part of these one-letter phonetic codes; we can put an l over here. Glutamic acid, on the other hand, is. So glutamic acid's one-letter code is e, and it is phonetic in origin. And so glu is for glutamic acid, and so glu will be e, and we can put it in red down below. Now, cys is specifically for cysteine, and cysteine does not have a phonetic one-letter code. And so that means it's going to be its first letter of just c. The same applies for ala, which is for alanine, and it's going to be a one-letter code of a, its first letter, since it's not phonetic in origin. And then asparagine, we know actually is. So asparagine's one-letter code is an n. And so, Asparagine has a phonetic 3-letter code, as well as a phonetic one-letter code of n. Now, ASP is specifically for aspartic acid, and aspartic acid actually has a phonetic one-letter code of a d. And so down below, we can put d for aspartic acid. And then the same goes for Tyrosine. Tyrosine is TYR, is its three-letter code, but its one-letter code is phonetic in origin, and it is a y. And so, down below for tyrosine, we can put a y. And so, really, we've completed this practice problem here, and the sentence that's revealed is just, "I like candy." And that completes this practice problem, so I'll see you guys in our next video.

Match the amino acid with the appropriate 1-letter-code.

Tyrosine ____                            1. W

Glutamine ____                         2. P

Glutamic Acid ____                   3. F

Proline ____                              4. Y

Tryptophan ____                       5. Q

Phenylalanine ____                   6. E

So this practice problem wants us to match the amino acid on the left over here with the appropriate one letter code on the right. And so whenever we hear one letter amino acid code, we want to think about our 8 amino acids with one letter codes of phonetic origin. And so the mnemonic that helps us memorize those 8 amino acids with phonetic one letter codes is just nerdy WQF, which of course we know stands for "nerdy Waldo qualifies in Fortnite." And so, each of these letters here represents the one letter code of an amino acid of phonetic origin. And we want to spend most of our time memorizing these phonetic one letter codes. So through spending enough time memorizing these one letter codes, we know that N is for asparagine, E is for glutamic acid, R is for arginine, D is for aspartic acid, Y is for tyrosine, W is for tryptophan, Q is for glutamine, and F is for phenylalanine. And so, looking at our first amino acid over here, notice it says tyrosine. And we know that tyrosine is like a Y, tie Y. And so tyrosine's one letter code is a Y, and it is in our phonetic one letter codes. And so because it is a Y, we can match it with the one letter code of Y, which is answer option 4. And so we can put a 4 over here. Now next, what we have is glutamine, and glutamine can really be, phonetically spelled as "cutamine." And so cutamine, if we were to put a Q here, then, what we could see is that it does have a phonetic one letter code of Q. And so because glutamine has a one letter code of Q, we can match it up with answer option 5 down below. And so we can cross off 54 since we've already matched them. Now, next what we have is glutamic acid. And, essentially, we can fill in the I here phonetically with an E. And so, what that means is that glutamic acid's one letter code is phonetic, and it is an E here. And so, because answer option 6 here is E, we can put 6 as, the glutamic acid one letter code, and we can go ahead and cross it off our list. So next, what we have is proline. And notice that proline is not one of the one letter codes of phonetic origin that we spent a lot of time committing to memory. And so because proline does not fall into this mnemonic up here, we know 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, of course, proline is not lysine, so it's not going to be K. But it is going to be the first letter of P, proline. And so what that means is it matches with answer option 2, so we can put a 2 here and cross off option 2. Now, next what we have is tryptophan. And you want to think, how would Bugs Bunny say tryptophan? And he would say it, "Twiptophan" with a W. And so, of course, that means that tryptophan has a phonetic one letter code of W and so we can go ahead and match it with answer option number 1. And, last but not least, what we have is phenylalanine. And of course, if we put an F here, in front of, phenyl, we can, phonetically, spell it. And so that means that its one letter code is going to be phonetic in origin, and it will be an F. And so, of course, that means that F, number 3 here is going to be the answer for phenylalanine. And so we can cross off all of these. So that concludes this practice problem, and I'll see you guys in our next video.

Here’s what students ask on this topic:

What are the one-letter codes for the 20 standard amino acids?

The one-letter codes for the 20 standard amino acids are as follows: Arginine (R), Asparagine (N), Aspartic acid (D), Glutamic acid (E), Glutamine (Q), Phenylalanine (F), Tryptophan (W), Tyrosine (Y), Cysteine (C), Histidine (H), Isoleucine (I), Methionine (M), Serine (S), Valine (V), Alanine (A), Glycine (G), Leucine (L), Proline (P), Threonine (T), and Lysine (K). The codes are derived either from the first letter of the amino acid or phonetic origins, making it easier to identify amino acids in protein sequences.

Why is it important to memorize the one-letter codes for amino acids?

Memorizing the one-letter codes for amino acids is crucial for efficiently analyzing and interpreting protein sequences. These codes are widely used in bioinformatics, molecular biology, and biochemistry to represent amino acids in a compact form. Understanding these codes allows students and researchers to quickly identify amino acids in protein structures, facilitating studies on protein function, interactions, and evolutionary relationships. Additionally, knowing these codes helps in writing and reading scientific literature where protein sequences are often presented using one-letter abbreviations.

What mnemonic can help memorize the phonetic one-letter codes for amino acids?

A useful mnemonic to memorize the phonetic one-letter codes for amino acids is 'nerdy WQF' or 'nerdy Waldo qualifies in Fortnite.' This mnemonic helps remember the eight amino acids with phonetic one-letter codes: Arginine (R), Asparagine (N), Aspartic acid (D), Glutamic acid (E), Glutamine (Q), Phenylalanine (F), Tryptophan (W), and Tyrosine (Y). By associating these codes with a memorable phrase, students can more easily recall the one-letter abbreviations during exams and practical applications.

How are the one-letter codes for amino acids determined?

The one-letter codes for amino acids are determined based on two main criteria: phonetic origin and uniqueness of the first letter. Eight amino acids have phonetic one-letter codes: Arginine (R), Asparagine (N), Aspartic acid (D), Glutamic acid (E), Glutamine (Q), Phenylalanine (F), Tryptophan (W), and Tyrosine (Y). For the remaining amino acids, the first letter of their name is used as their one-letter code if it is unique. If the first letter is not unique, the more commonly found amino acid in proteins is prioritized. Lysine is an exception, using 'K' as its code because 'L' is already taken by Leucine.

What are the challenges in memorizing the one-letter codes for amino acids?

The main challenge in memorizing the one-letter codes for amino acids lies in the phonetic origins of some codes, which are not always intuitive. For example, Glutamine is represented by 'Q' and Tryptophan by 'W,' which do not directly correspond to their names. Additionally, distinguishing between amino acids with similar starting letters, such as Leucine (L) and Lysine (K), can be difficult. Using mnemonics and understanding the rationale behind the codes can help overcome these challenges, making it easier to recall the correct one-letter abbreviations.