Ek1001 #165

[Temperature101]

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Which of the following DNA lesions will NOT result in a frameshift mutation.

A. 1 missing base pair
B. 2 altered base pairs
C. 3 deleted base pairs
4. 2 inserted base pairs.

I thought the answer was C. For some reason, EK says that the answer is B. I think frameshift mutation occurs whenever the number of nucleotides inserted or deleted in not a multiple of three since each codon is three nucleotides. Am I wrong? This is suppose to be an easy question and EK answer said that I miss it.

 

[MShopes]

Which of the following DNA lesions will NOT result in a frameshift mutation.

A. 1 missing base pair
B. 2 altered base pairs
C. 3 deleted base pairs
4. 2 inserted base pairs.

I thought the answer was C. For some reason, EK says that the answer is B. I think frameshift mutation occurs whenever the number of nucleotides inserted or deleted in not a multiple of three since each codon is three nucleotides. Am I wrong? This is suppose to be an easy question and EK answer said that I miss it.

You are thinking that the three deleted base pairs are actually next to each other making one codon and therefore the deleted codon would not result in non-multiples of three right? That is the only reasoning I could figure out from why you chose C? Well you would be right in thinking that way but the choice C didn't indicate if they were next to each other or not. If they are just three deleted base pairs that are not next to each other, then sure they can result in non-multiples of three and therefore it is a frameshift mutation. Any ways without thinking much, any frameshift mutation would include deletions or insertions. So once you see a choice with no insertion or deletion (i.e choice B which involves base-pair mutation which is just alteration in one base pair), then it would not be frameshift mutation. For your info, basepair mutations like choice B are actually non-frameshift mutation and EK stated that.

 

[Temperature101]

You are thinking that the three deleted base pairs are actually next to each other making one codon and therefore the deleted codon would not result in non-multiples of three right? That is the only reasoning I could figure out from why you chose C? Well you would be right in thinking that way but the choice C didn't indicate if they were next to each other or not. If they are just three deleted base pairs that are not next to each other, then sure they can result in non-multiples of three and therefore it is a frameshift mutation. Any ways without thinking much, any frameshift mutation would include deletions or insertions. So once you see a choice with no insertion or deletion (i.e choice B which involves base-pair mutation which is just alteration in one base pair), then it would not be frameshift mutation. For your info, basepair mutations like choice B are actually non-frameshift mutation and EK stated that.

Thanks..I assumed the three deleted base pairs were next to each other.

 

[MShopes]

Thanks..I assumed the three deleted base pairs were next to each other.

Np...the choice didn't indicate that so we shouldn't assume it...however if that was the case, then your logic is right...you seem to master the material...good luck!

 

[MT Headed]

Judging by the answer in the back of the book, I think it it is a misprint and it was supposed to say "C. 2 deleted base pairs". It sounds like you know what's going on, so I wouldn't worry about it.