Transcription question

[indsha008]

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The base sequences of codons 57-58 in the cytochrome b5 reductase gene is CAGCGC. The mRNA produced upon transcription of this gene will contain the sequence :

A. GCGCTG
B. CUGCGC
C. GCGCUG
D. CAGCGC
E. GUCGCG

Dumb explanation given to it in the notes. Cant understand it..

Thanks

 

[bbydoc]

The base sequences of codons 57-58 in the cytochrome b5 reductase gene is CAGCGC. The mRNA produced upon transcription of this gene will contain the sequence :

A. GCGCTG
B. CUGCGC
C. GCGCUG
D. CAGCGC
E. GUCGCG

Dumb explanation given to it in the notes. Cant understand it..

Thanks

Its C.
As for the explanation:
It can either be C or E.
the 3-5 DNA sequence is CAGCGC.
but mRNA is produced from 5-3. so it has to be C.
see how E is C 3-5? thats how they try to trick you.

 

[indsha008]

Hi bbydoc. Thanks for your reply ...

THis question is in Kaplan Lecture notes ...
THey have given right answer as D. Explanation given is that - "since the sequence in the question stem represents a coding strand, mRNA is same as coding strand except replacing T with U"..

I dont get it how is the bp in question from a coding strand !!

I also chose C 🙁 ...

any suggestions or is the answer wrong ?

 

[bbydoc]

Hi bbydoc. Thanks for your reply ...

THis question is in Kaplan Lecture notes ...
THey have given right answer as D. Explanation given is that - "since the sequence in the question stem represents a coding strand, mRNA is same as coding strand except replacing T with U"..

I dont get it how is the bp in question from a coding strand !!

I also chose C 🙁 ...

any suggestions or is the answer wrong ?

DAMN!
The kaplan answer is right!
C would be the right answer if the sequence in the stem was the anti-sense strand, the strand oppoiste to the sense strand!
Me and you assumed they gave us the codons that is copied (the anti-sense strand bit). but they just gave the gene which is on the sense strand! and the sense strand (coding strand) as mentioned in the explanation is the same as mRNA sequence.

 

[indsha008]

DAMN!
The kaplan answer is right!
C would be the right answer if the sequence in the stem was the anti-sense strand, the strand oppoiste to the sense strand!
Me and you assumed they gave us the codons that is copied (the anti-sense strand bit). but they just gave the gene which is on the sense strand! and the sense strand (coding strand) as mentioned in the explanation is the same as mRNA sequence.

But where does it mention that it is not the template strand but the coding strand ? I still dont get it !!

 

[bbydoc]

But where does it mention that it is not the template strand but the coding strand ? I still dont get it !!

well it is not mentioned specifically but it is implied, it says gene and genes are on the coding strand, so you have to assume it is on the coding strand unless told otherwise. thats my understanding.

 

[engineeredout]

Wow what a load of ****. Who cares about these kinds of semantics besides awkward biochemists who wear bow ties and their pants up to their nipples?

 

[iblunk]

Yeah...this is kind of a ****ty semantics questions. I would've missed it too. Reading it again, I think b/c it says "codon" which correspond with amino acids. If they just said gene, i would still assume they were talking about the template strand.