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  #1  
Old 04-13-2010
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Molecular mRNA OK but no Enzyme Activity?

A 2-month-old, breast-fed baby that was normal at birth begins to develop GI problems and cirrhosis of the liver. Molecular analysis indicates a normal amount of galactose-1-phosphate uridyl transferase mRNA, but no observable enzyme activity. Which of the following would be the best possible explanation for this?


A. Gene deletion
B. Nonsense mutation
C. Premature transcription termination sequence in the DNA
D. Promoter mutation
E. RNA splicing mutation
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Old 04-14-2010
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could it be D- promoter mutation?
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Old 04-14-2010
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Default mRNA ok but no enzyme activity

i think the and is nonsense mutation bcos of early stop codon. pls post the ans.
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Old 04-14-2010
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I also think D
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Old 04-14-2010
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Yeh i think ur rt. it could be D
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Old 04-15-2010
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you got it wrong guys.The correct answer is B.
A nonsense mutation is a mutation in the DNA that leads to a premature stop codon when the mRNA is being translated into protein. The mRNA would be transcribed correctly, but when the protein was being translated, it would be stopped prematurely, leading to a truncated protein.

A promoter mutation in the DNA, if it caused the gene in question to be less actively transcribed would result in a diminished amount of message
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Old 04-15-2010
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Quote:
Originally Posted by sam01 View Post
you got it wrong guys.The correct answer is B.
A nonsense mutation is a mutation in the DNA that leads to a premature stop codon when the mRNA is being translated into protein. The mRNA would be transcribed correctly, but when the protein was being translated, it would be stopped prematurely, leading to a truncated protein.

A promoter mutation in the DNA, if it caused the gene in question to be less actively transcribed would result in a diminished amount of message
arrgghhh!!... lol...thx. honestly i looked at it again, and u're so ryte!! i was actually lazy to think of what nonsense mutation meant again.

thank u thank u.

here's an idea. post more questions on biochem if u come across any. i need this teaching!
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Old 04-15-2010
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Quote:
Originally Posted by Seetal View Post
arrgghhh!!... lol...thx. honestly i looked at it again, and u're so ryte!! i was actually lazy to think of what nonsense mutation meant again.

thank u thank u.

here's an idea. post more questions on biochem if u come across any. i need this teaching!
No prob.i m posting one right now
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Old 07-24-2010
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if the translation is terminated quickly then how could it become galactose 1 phosphate uridyl transferase it would become a different protein with less no of amino acids no sam pls explain it in a more detailed way
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Old 07-24-2010
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Smile Who said it's still there!

Quote:
Originally Posted by devareddy View Post
if the translation is terminated quickly then how could it become galactose 1 phosphate uridyl transferase it would become a different protein with less no of amino acids no sam pls explain it in a more detailed way
Who said it's still G1PUT, the question is saying G1PUT mRNA, it did not say G1PUT protein
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Old 07-24-2010
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now i understood laith thanks
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  #12  
Old 07-29-2011
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B ) kaplan q bank question ...
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