molec bio q

[BombayBombshell]

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since you guys are soooo good at answering my oh so random questions.... here's another one 🙂 ...it's a stupid little molec bio question...i haven't taken biochem since undergrad so the old gray matter is having a tough time...here ya go:

a nucleotide encoding 4 aa nr the amino end terminus of a 10kd protein 5 ACT GAT TGC GTT 3...and then this sequence is mutated by a inserting A in the second condon so basically you have now ACT GAA TTG CGT . so what is likely to follow? a. altered cell-cycle checkpoint b. decr. rate of transcription c. protein truncation d. single aa subs

so i dont see any stop codons so i r/o 'C.'..r/o 'D' because, well, you arent adding an extra aa just a nucleotide...anyway i went w/ A. figured a mutation would screw up cell-cycle checkpoint?!! ok ok so i'm pulling stuff out of my a$$...can ya tell?!
~brin

 

[Idiopathic]

I would say protein truncation. Anytime you have a framshift mutation, you are likely to encounter a stop codon earlier than you normally would have otherwise. Just because it aint there, dont mean it aint happening. The others dont make sense to me.

Me, also pulling things out of you-know-where.

 

[MedicinePowder]

that's a pretty good question. i would go with truncated protein. as our in-hourse attending, Idiopathic noted: frameshift mutations are likely to lead to truncated proteins.

 

[inositide]

The answer is definitely truncated protein. Whenever they ask you the consequence of a framshift mutation, the answer is almost always that it resutls in a truncated protein. The reason is that although you dont see a stop codon in the sequence they give you in the question, but it is assumed that you will encounter a stop codon somewhere along the way. just make sure to read the question to make sure they dont say that this region is some kind of specific promoter or enhancer, because in that case, you would get decreased mRNA. This is a very common question on board type exams so I would just memorize it as such. Don't go searching for the stop codon.

 

[BombayBombshell]

yay!! thanks!!....now, if someone can tell me how i can log onto sdn during the test, i'm golden 🙂 ... till then i guess i'll just have to keep at it... 🙁

thanks everyone!!!

brin