Use the genetic code table in the chapter and the DNA sequence below to answer the following questions:
3'-TACATAAAATAATGGCGTTCTATT-5'
a. What would the mRNA sequence be, based on the provided DNA sequence?
b. What would the corresponding polypeptide sequence be for this DNA sequence?
c. What tRNA anticodon loop would correspond to the third codon of the mRNA?
d. What would the mRNA and polypeptide sequences be if the second adenine in the DNA was deleted?

Question

Use the genetic code table in the chapter and the DNA sequence below to answer the following questions:

3'-TACATAAAATAATGGCGTTCTATT-5'

a. What would the mRNA sequence be, based on the provided DNA sequence?

b. What would the corresponding polypeptide sequence be for this DNA sequence?

c. What tRNA anticodon loop would correspond to the third codon of the mRNA?

d. What would the mRNA and polypeptide sequences be if the second adenine in the DNA was deleted?

Accepted Answer

Hi everybody. The next question says, the sequence of the coding strand of A DNA is five prime and then a TGCCC TT GCTAATC three prime, what will be the sequence of MRN, a transcribed from this coding strand of DNA? We have four answer choices. Um And one thing that's important to note is that some are written in the three prime to five prime direction and others in the five prime to three prime direction, you always have to be aware of that with DNA or RN A sequences that we're going in the right direction. So we're given our DNA sequence in the five prime to three prime direction. But we need to remember what coding strand means. We can get ourselves a little confused um when we're trying to think about which DNA strand is being copied. So we have the DNA, we have a coding strand. And if that's in the five primed to three prime direction, we would have a complimentary template strand. So that will have complementary base pairs in the three prime to five prime direction. So that will be our double helix. And then I'll draw in red, I have the DNA in blue, when the MRN A is synthesized, it is complementary to the template strand. That's why it's called the template strand is a template for the new RN A molecule. So our MRN A is now in the five prime to three prime direction. Notice that this will make our MRN A strand identical to the coding strand of DNA except for the T bases in DNA. The thy means being replaced by Uricol in the MRN A, which is why it gets its name of coding strand. Since you can look at the DNA code, know what the RN A sequence will be and then what the code on for the protein will be. But sometimes I almost always write it out like this with the three strands just so I don't get myself turned around and mixed up what I'm thinking about what the base sequence should be and which direction it's going in. So we know our MRN A needs to be identical to the DNA sequence we're given with the exception of replacing teas with U. So let's look through our answer. Choices. Choice A is written in the three prime to five prime direction. So we actually need to start from the right hand side to check it. So that's important, I'm going to write a little arrow going in that direction. So I have five prime and then CT A. So I already know it's incorrect because it's the, it's matching up with the other direction. So when we look at this choice A, it's written three prime A TGCCC, it's identical, including TS, but written three prime to five prime. So it's just mixed up in both ways. Um And not our correct answer. So let's look at choice B, it's written in three prime to five prime or excuse me, the five prime to three prime direction. So we can start reading left to right. And we see our first three DNA bases are a TG. And here we have a UG. So that's correct. Same order U replace this T and then CCC and then the DNA has TT G. So our R A has our DNA has CT A and we have CU A on the RN A and then our DNA has a TC and our RN A has a UC. So choice B is in the correct direction, the correct order and with the U in there correctly. So it is our answer and we'll just briefly look at CND even though we know they're incorrect. Which C choice C uh it's a matching sequence with the usual placing TS, but it's in the wrong order as it's written three prime to five prime. And then choice D is written three prime to five prime. So we'd have to again look from the right hand side and we see that it is not correct. It's actually complementary to the coding strand of the DNA rather than the same sequence. So at least what looking briefly at the right hand side, so that's incorrect as well. So once more, the correct sequence of MRN A transcribed from this coding strand of DNA is choice B in which it is identical in sequence except for replacing the TS with use and also in the same direction five prime to three prime as the coding strand is written. See you in the next video.

Verified video answer for a similar problem:

Key Concepts

Transcription and mRNA Synthesis

Genetic Code and Translation

tRNA Anticodon and Codon-Anticodon Pairing