Convention for Anticodon

[SoulinNeed]

If we see on the MCAT an anticodon written AGG, should we assume that it's written 5-3, because that is the convention for regular codons, or will they identify the direction on the exam?

If this anticodon is AGG, written 5-3, would that make the codon CCU, following the convention that codons are written out in their 5-3 convention? I guess my main question is, should I always write things out 5-3, codons and anticodons? Thanks.

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[MedPR]

If we see on the MCAT an anticodon written AGG, should we assume that it's written 5-3, because that is the convention for regular codons, or will they identify the direction on the exam?

If this anticodon is AGG, written 5-3, would that make the codon CCU, following the convention that codons are written out in their 5-3 convention? I guess my main question is, should I always write things out 5-3, codons and anticodons? Thanks.

Yes, If MCAT has an anticodon written "AGG" then its corresponding codon is 3'-UCC-5'. I'm pretty sure the 5'-3' designation will be made to avoid ambiguity, unless it is a question that is directly testing your knowledge of 5'-3' processing.

 

[ljc]

Yes, If MCAT has an anticodon written "AGG" then its corresponding codon is 3'-UCC-5'. I'm pretty sure the 5'-3' designation will be made to avoid ambiguity, unless it is a question that is directly testing your knowledge of 5'-3' processing.

This. Sometimes answer choices will be provided 3->5 just to try and trip you up, but in general, EVERYTHING is written 5->3, unless otherwise noted. If there is no 5'-3' or 3'-5' designation, assume it is 5'-3'. Although for what it's worth, I've only ever seen one question (on practice MCATs) that didn't write out the designation, and the question was simply asking "AUGUUAA (or something similar) -- Is this strand RNA or DNA?," so such a designation would have been completely pointless.

 

[MedPR]

This. Sometimes answer choices will be provided 3->5 just to try and trip you up, but in general, EVERYTHING is written 5->3, unless otherwise noted. If there is no 5'-3' or 3'-5' designation, assume it is 5'-3'. Although for what it's worth, I've only ever seen one question (on practice MCATs) that didn't write out the designation, and the question was simply asking "AUGUUAA (or something similar) -- Is this strand RNA or DNA?," so such a designation would have been completely pointless.

Doing TBR passages/questions makes you think questions like that would never ever ever ever ever show up on an MCAT. I'm really hoping these TBR passages end up being significantly harder than MCAT.

 

[ljc]

Doing TBR passages/questions makes you think questions like that would never ever ever ever ever show up on an MCAT. I'm really hoping these TBR passages end up being significantly harder than MCAT.

It's from AAMC Bio 5R. I had to stop a second and think "is that REALLY what they're asking?"

The actual question is:
A researcher has a short polynucleotide strand with the following base sequence: AUCCCUGG. This strand must be:
A) Template DNA
B) DNA
C) RNA
D) a peptide

 

[MedPR]

It's from AAMC Bio 5R. I had to stop a second and think "is that REALLY what they're asking?"

The actual question is:
A researcher has a short polynucleotide strand with the following base sequence: AUCCCUGG. This strand must be:
A) Template DNA
B) DNA
C) RNA
D) a peptide

Template DNA for sure 😉

 

[SaintJude]

Sorry, just to be clear..the answer is D? The base sequence they are referring to is an RNA anticodon-doesn't that translate to a mRNA message of a peptide?

 

[milski]

Sorry, just to be clear..the answer is D? The base sequence they are referring to is an RNA anticodon-doesn't that translate to a mRNA message of a peptide?

C. He has a polynucleotide. It has A/G/C/U nucleotides, which means it's an RNA. DNA would have A/G/C/T and a peptide would not be a polynucleotide nor really a strand.

 

[MedPR]

Sorry, just to be clear..the answer is D? The base sequence they are referring to is an RNA anticodon-doesn't that translate to a mRNA message of a peptide?

It's C. The question is about a string of nucleotides, making it either DNA or RNA. Since there are uracils, it is RNA. To be a peptide, it would have to be a string of amino acids, which consist of a side chain, carboxyl group, and amine group. The side chain, of course, is coded for by a 3 nucleotide codon.

 

[Temperature101]

Looking at the question, I thought it was a very easy question. But when I see people answer anything other than C (RNA)..I said to myself: Am I missing something here? Glad to know the answer is C...It can not be a peptide since it is not a multiple of three nucleotide (codon), which specifies AA...It is not a templale DNA or a DNA due to uracil in the strand. By the way, I dont think we should expect easy question like that in the mcat...

 

[ljc]

Looking at the question, I thought it was a very easy question. But when I see people answer anything other than C (RNA)..I said to myself: Am I missing something here? Glad to know the answer is C...It can not be a peptide since it is not a multiple of three nucleotide (codon), which specifies AA...It is not a templale DNA or a DNA due to uracil in the strand. By the way, I dont think we should expect easy question like that in the mcat...

That's from an official AAMC practice test. From my experience with practice tests, there are at least 2-3 like this on each test. They test something so basic that it trips many people up, who begin second guessing themselves, and then get it wrong. It's a test of how confident you are in the material.

 

[SaintJude]

Very true, I thought it was C at first. But then, thought "hmm..too easy-- Am I missing something?" And because, as ljc said, I wasn't clear on my definition of what a base sequence was, I second-guessed myself and then opted for another wrong answer choice.

Now I'm clear on the fact that A base sequence is simply "the order of the nucleotide bases in a DNA or RNA molecule" But, perhaps it's something to be ashamed of, I just wasn't sure of this prior to this question.

 

[Class1P]

The more I study for the MCAt the more I realize it really is all about how confident you are with the material. Even if you don't know the correct equation, as long as you deeply understand the concept you can usually get the answer right.