An enzyme is required to convert the inactive form of a drug into the active form.A completely dominant change from the G to the C allele increases activity of the enzyme.Too much of the active form of the drug can lead to tremors.Too little of the active form of the drug renders it ineffective.Which scenario is most likely?
A) Individuals with the GC genotype are more likely to have tremors from the drug than those with CC.
B) Individuals with the GC genotype are more likely to have tremors from the drug than those with GG.
C) The drug is more likely to be ineffective in individuals with the GC genotype than in those with GG.
D) The drug is more likely to be just as effective in individuals with the GC genotype as in those with CC.
E) The drug is less likely to be ineffective in individuals with the GG genotype than those with GC.

Question

Quizplus · Accepted Answer

The GC genotype results in increased activity of the enzyme, which can lead to too much of the active form of the drug, causing tremors. Therefore, individuals with the GC genotype are more likely to have tremors from the drug than those with GG. Option A is incorrect because CC genotype is expected to have even higher activity of the enzyme than GC, which would lead to even more tremors. Option C is incorrect because individuals with the GC genotype have more active enzyme and would therefore have more active drug, making it less likely to be ineffective. Option D is incorrect because CC genotype would have even higher enzyme activity than GC, which would make the drug more effective. Option E is incorrect because individuals with the GG genotype would have lower enzyme activity, which would result in less active drug and potentially render it ineffective.

An Enzyme Is Required to Convert the Inactive Form of a Drug