Bio Question(examkrackers)

[Ali-karimi]

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allright,

I have one question form 1001 bio ek( even though the question is really easy but i get confused). the question is:
which of the following DNA lesions will not result in a frame shift mutation?
A. 1 missing base pair
B. 2 altered base pair
C. 3 deleted base pairs
D 2 inserted base pairs

I did eliminate choice A and D but i think B and C are both right..Any Idea ? your help will be appreciated.

 

[mj1878]

allright,

I have one question form 1001 bio ek( even though the question is really easy but i get confused). the question is:
which of the following DNA lesions will not result in a frame shift mutation?
A. 1 missing base pair
B. 2 altered base pair
C. 3 deleted base pairs
D 2 inserted base pairs

I did eliminate choice A and D but i think B and C are both right..Any Idea ? your help will be appreciated.

In all answers except B you have base pairs either inserted or deleted. C is basically the same as A, unless the three bps that are deleted constitute a frame themselves, which it doesn't say. With B, you are neither inserting nor deleting any base pairs; you are only altering them, which means that you're swapping A for G or C for T or something like that. It won't cause a frame shift, because the number of base pairs in the DNA has not changed.

 

[Sundarban1]

If you go to examkrackers.com there is a forum where you can ask questions about problems from the subject books, for future reference of course.

 

[pslee]

I guess that Answer is three because it is in multiple of three. because the added(or deleted) nucleotides are in multiple of three, it wouldn't cause much of a problem for translation. It is in section 2 of the EK biology book.

 

[pslee]

😡

 

[pslee]

 

[DrChandy]

allright,

I have one question form 1001 bio ek( even though the question is really easy but i get confused). the question is:
which of the following DNA lesions will not result in a frame shift mutation?
A. 1 missing base pair
B. 2 altered base pair
C. 3 deleted base pairs
D 2 inserted base pairs

I did eliminate choice A and D but i think B and C are both right..Any Idea ? your help will be appreciated.

The answer is C, because eliminating 3 consecutive base pairs will result in the loss of one amino acid, but the reading frame will still be conserved.

 

[remo]

The question doesn't sound like it was worded very well but the answer is probably C. B (altering 2 bases) could cause a frameshift if it changed where the start site was.

 

[laputan]

Yea, I remember that question. I put C and got it wrong. As mj explained, the "3 deleted basepairs" are not necessarily 'in-frame', (also they may not even be consecutive), so B is the only one where basepairs are only "altered", and there's no shifting of the reading frame.

That book rocks by the way, I'm upto 12 in BS and it's Feb.

 

[pslee]

actually,laputan is correct. Altered pair is change such as A-T into T-A, which might not cause major damage in translation. Others might be changing the sequence entirely. Sorry for my misunderstanding. The answer i think is B.

 

[KeyLime]

I would have missed it by putting C has the correct answer also. That's a tricky one.

 

[DrBowtie]

Initially when you think of frame shift you think of 1 or 2 bp insertion so naturally kinda jumps out at you as the right answer.

However, while as someone said if the 3 were nonsequential then it would be the same as 3 separate frameshifts.

B must be the correct answer since it would worst case scenario produce a wrong protein but the reading frame would be uninterupted.

 

[DrChandy]

Edit: B is correct. Sorry for the confusion.

As previous posters pointed out, C is applicable only if the deletion is sequential, which the problem does not state that it is.