AAMC Bio Question Pack Volume 1 #29

[bellowbruins]

Hello,

I am so confused with the question 29. I thought A is the answer but then AAMC said it is D and its explanation makes me even more confused. It's like I kinda get it but not really lol. Please help me

Qn 29) Phenylketonuria is a genetic disorder caused by mutation in the gene for the enzme phenylalanine hydroxylase, which eliminates its enzymatic activity. Could an antisense drug help individual with this order?
A. Yes, if it binds to the mRNA of the phenylalanine hydroxylase gene and prevents its translation.

B. Yes, if it is incorporated into the chromosomes and prevents the expression of the phenylalanine hydroxylase gene.

C. No, because mRNA does not persist in the cytoplasm of the cell.

D. No, because blockage of phenylalanine hydroxylase gene expression will not remedy the original disorder.

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[joe_1395]

It's D because the disease is associated with a dysfunctional enzyme, not the gene. Repressing the gene will not have an effect on the specific enzyme

 

[bellowbruins]

Hello, I thought when you bind the gene, all the products could have improved? yes no? I am so confused by the wording

 

[joe_1395]

an antisense drug will prevent the gene from becoming what it's supposed to become. you essentially inhibit it's translation so you will not fix the problem of PKU

 

[Gswish12]

A little late to the party but i guess this would be helpful for anyone in the future....The answer is D because the antisense mRNA binds to the sense mRNA, and therefor disables it. In this specific question, an antisense drug for someone with a dysfunctional gene/protein would disable that gene/protein from being expressed. But remember, the person is suffering from a dysfunctional protein, and when you take away that protein they now have no dysfunctional protein...and no proper functioning protein bc they have a genetic mutation. So in short, taking away a broken enzyme means that there is now no enzyme at all. No good enzyme, no bad enzyme. Both result in a bad outcome that doesnt fix the problem.

 

[BobbyKoch]

A little late to the party but i guess this would be helpful for anyone in the future....The answer is D because the antisense mRNA binds to the sense mRNA, and therefor disables it. In this specific question, an antisense drug for someone with a dysfunctional gene/protein would disable that gene/protein from being expressed. But remember, the person is suffering from a dysfunctional protein, and when you take away that protein they now have no dysfunctional protein...and no proper functioning protein bc they have a genetic mutation. So in short, taking away a broken enzyme means that there is now no enzyme at all. No good enzyme, no bad enzyme. Both result in a bad outcome that doesnt fix the problem.

only took a year, but I agree this is a better answer.