EK Bio 1001 Wrong Answer? (need confirmation)

[Spiker]

Which of the following DNA lesion will NOT result in a frame shift mutation?

1 missing base pair (frame shift)
2 altered base pair (no frame change)
3 deleted base pairs (in frame mutation)
2 inserted base pairs

Answer is B

However in the explainiation it specifically explained that adding/deleting 3 bases are in frame therefor are not frame shift mutation...

I subscribed to their damn forum for nothing!

Btw does anyone else feel that alot of their passage based problems are BS?? Like it cite something in the passage for as support, but when you look back at the passage it still doesnt really support the answer.

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[Marcus Brody]

EK 1001 books are abound with errors. They pay interns to write them up, seemingly off the tops of their heads. I wouldn't spend more than 20 seconds thinking about a strange/incorrect sounding EK question. There's 1000 others...

 

[G1SG2]

Which of the following DNA lesion will NOT result in a frame shift mutation?

1 missing base pair (frame shift)
2 altered base pair (no frame change)
3 deleted base pairs (in frame mutation)
2 inserted base pairs

Answer is B

However in the explainiation it specifically explained that adding/deleting 3 bases are in frame therefor are not frame shift mutation...

I subscribed to their damn forum for nothing!

Btw does anyone else feel that alot of their passage based problems are BS?? Like it cite something in the passage for as support, but when you look back at the passage it still doesnt really support the answer.

I don't see what's wrong with that answer? Altered base pair means the base pair itself was changed. For example, Suppose you originally had:

XXY-XXY-XXY-XXY

and you changed it to

XXX-XXY-XXY-XXY

You simply altered/changed a base and thus the base pairing-you did not insert or delete a base. The codons are still going to be read in their original frame.

However in the explainiation it specifically explained that adding/deleting 3 bases are in frame therefor are not frame shift mutation...

Answers A, C and D do not say anything about adding or deleting in multiples of 3. A and C are the same (deletions); D is an insertion. Unless otherwise stated, assume they are not in multiples of 3 and will cause a frameshift.

 

[MD2B in 2010]

Which of the following DNA lesion will NOT result in a frame shift mutation?

1 missing base pair (frame shift)
2 altered base pair (no frame change)
3 deleted base pairs (in frame mutation)
2 inserted base pairs

Answer is B

However in the explainiation it specifically explained that adding/deleting 3 bases are in frame therefor are not frame shift mutation...

I subscribed to their damn forum for nothing!

Btw does anyone else feel that alot of their passage based problems are BS?? Like it cite something in the passage for as support, but when you look back at the passage it still doesnt really support the answer.

The reason why choice B is right is because a frameshift mutation is specifically "deletions or insertions", not alterations or substitutions in DNA. Alterations in DNA make point mutations, non-sense/missense/sense codons, etc.., but a frameshift mutation is specifically deletions/insertions in DNA that change the reading frame. Hope this helps, its definitely correct and that is not an error.

 

[244869]

However in the explainiation it specifically explained that adding/deleting 3 bases are in frame therefor are not frame shift mutation...

I was wondering the same thing...but i encountered this in the kaplan review!!!

It doesn't make sense why they say addition/deletions in sets of 3's do not cause a frame shift because it is...

ATA-GCG-TAT-CGC

add 3 base pairs

ATA-ATA-GCG-TAT-CGC

The reading frame has shifted...

 

[G1SG2]

I was wondering the same thing...but i encountered this in the kaplan review!!!

It doesn't make sense why they say addition/deletions in sets of 3's do not cause a frame shift because it is...

ATA-GCG-TAT-CGC

add 3 base pairs

ATA-ATA-GCG-TAT-CGC

The reading frame has shifted...

No, it has not shifted. A shift from ATA-GCG-TAT-CGC would look like this (suppose we add two bases, G and C):

AGC TAG CGT ATC GC(next base), etc...

Every codon after GC is read incorrectly. Codon 2 is read as TAG instead of GCG, three as CGT intead of TAT, and so on. We disrupted the reading frame, and essentially "shifted it". In your example:

ATA-GCG-TAT-CGC

add 3 base pairs

ATA-ATA-GCG-TAT-CGC

ATA, GCG, TAT, CGC are still read as they are in the original reading frame. You just added an extra codon, but did not disrupt the reading of the original codon. In short: to shift the reading frame, you need to disrupt the reading of the codons in their multiples of 3. If you retain the original codon, there is no frameshift. ATA before=ATA after=no frameshift. ATA before does not =AGC after: thus, there is a frameshift.

 

[244869]

No, it has not shifted. A shift from ATA-GCG-TAT-CGC would look like this (suppose we add two bases, G and C):

AGC TAG CGT ATC GC(next base), etc...

Every codon after GC is read incorrectly. Codon 2 is read as TAG instead of GCG, three as CGT intead of TAT, and so on. We disrupted the reading frame, and essentially "shifted it". In your example:

ATA-GCG-TAT-CGC

add 3 base pairs

ATA-ATA-GCG-TAT-CGC

ATA, GCG, TAT, CGC are still read as they are in the original reading frame. You just added an extra codon, but did not disrupt the reading of the original codon.

So even though an extra codon was added, there is no frame shift.

Now does this apply to the addition of bases as long as it is in multiples of 3? How about non consecutive addition (not in a string of 3)?

 

[G1SG2]

So even though an extra codon was added, there is no frame shift.

As long as they are in multiples of three, then there is no frameshift.

Now does this apply to the addition of bases as long as it is in multiples of 3?

Yes.

How about non consecutive addition (not in a string of 3)?

Those would alter the reading frame. They have to be in a set of 3, inserted together in order to prevent a frameshift. If they are inserted randomly, then they would change the reading frame, and give you a frameshift mutation.

 

[bkz]

ek has an errata forum but im pretty sure you have to pay to see it Someone here may have posted the list though, I'll edit the link back in if I find it

 

[muhali3]

That's an easy question, and those damn EK interns got it wrong.

Anyways, yeah if 3 base pairs are inserted/deleted that means there will only be one extra/less amino acid created, but the rest of the codons will be read correctly.

 

[buccsmf1]

ek has an errata forum but im pretty sure you have to pay to see it Someone here may have posted the list though, I'll edit the link back in if I find it

i paid to access and it's a complete scam. they have ZERO errors listed under ANY of the 1001 questions. so apparently all 4004 of those questions have no errors..... what a joke

edit: going through my 1001s and i just found the 3rd error in the book that has been confirmed on the forum but not added to the errata section. apparently this error has been around since the 2004 edition of the book and it's still here.............. 5 years later in 09...............

 

[Spiker]

Lol i paid for it too.

So now looking back on it. Both B or C should be acceptable right?

 

[UTsksk]

B is correct, but C is in 2nd. Choice C may not cause a frameshift if there was a deletion of 3 to take away that entire codon. If that happened, there'd be one less amino acid, but the part I'm not too sure with is if that'd completely effect the sequence after that, which would lead to a frameshift. Even if I was partially right about C, B is still the best answer because it does not entail inserting or deleting.

 

[0Complications]

Lol i paid for it too.

So now looking back on it. Both B or C should be acceptable right?

I think you should go with B. I don't think C is correct. It is still a frame shift mutation.

B is the only answer that is clearly not a frame shift mutation. While deleting 3 base pairs could be less catastrophic to the organism, it is still going to shift the frame of all the subsequent bases.