Consider a DNA template strand of the following sequence: 5'-A...

Question

Consider a DNA template strand of the following sequence: 5'-A C T G C C A G G A A T-3'.

A) What is the sequence of the corresponding DNA coding strand? Include directionality.

DNA Template Strand: 5'-A C T G C C A G G A A T-3'.

DNA Coding Strand:

B) What is the sequence of the corresponding mRNA strand? Include directionality.

mRNA Strand:

Accepted Answer

Okay, everyone. Consider a DNA template strand of the following sequence. What is the sequence of the corresponding DNA coding strand include directionality? Okay. So we have our particular strand of DNA basis here, and we're trying to find what is the sequence of the coding strand. So remember when we're talking about transcription and translation, an mRNA or an RNA transcript that is complementary to the an mRNA or an RNA transcript that is complementary to the template strand. And the coding strand is the other strand that is not used by RNA polymerase. However, the coding strand gets its name because it should have the same code as the RNA being created because it is also complimentary to the template strand. But it's a little bit different because remember that RNA has Us instead of Ts, and DNA has Ts instead of Us. So remember that DNA has thymine, while RNA will have uracil. Okay? Don't forget that. Okay. So what we have to do first is we have our template strand here in yellow, and we just need to find the complementary DNA coding strand. So the first thing that I like to do is I like to put my in order. I like to identify the ends of the strand of nucleotides, and we know that the template strand and the coding strand should be anti parallel to one another, meaning they're going in different directions. So I can see that this end of the template strand is 5 prime. So I'm going to make this end of the coding strand 3 prime, and this one down here 5 prime. So now, I know for sure that they are anti parallel. So now, I can go through and I can make the complimentary bases. So the first base I have here is a, so that means we need a t, and then gac ggtc. Oh, running out of room. I'm gonna have to move this. T t a, put my 5 prime back on. Okay. So now if you're doing a worksheet or homework or a test, I would always recommend going back and double checking that your complimentary bases are correct and that you wrote everything down well because that's a super common mistake. So everything looks good to me. So that is going to be our DNA coding strand complementary to our template strand. So now the next part of the question says, what is the sequence of the corresponding mRNA strand? Again, include directionality. So the mRNA strand that is being created should be complementary to the template strand just like the DNA coding strand. So now for simplicity, you could just do the same thing and make and figure out which of bases are complementary just like we did for the coding strand, or we could just write the code of the DNA coding strand and replace all the t's with us. Because if you think about it, the DNA coding strand is complementary to the template strand and so is the mRNA. We just have to make sure that there are no thymines in our mRNA and replace those thymines with uracils. So, again, we're just gonna pretty much rewrite what we've already got. But instead of a t that I see here and here and right here, I'm just gonna replace them with uracils. So we're gonna have u g acgguccuua5 prime. And this makes total sense because the directionality is correct. Technically, the mRNA strand is still anti parallel to the DNA template strand, and it has the same code as the coding strand, except it has uracils instead of thymeins. Okay, everyone. Hopefully, that makes sense. Let's move on to our next video.

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