[Campbell Biology P.894] Based on the information provided, if the sexual dysfunction drug V... | Practice Question

Based on the information provided, if the sexual dysfunction drug Viagra inhibits an enzyme that breaks down cyclic GMP cGMP , and assuming tomato leaf cells have a similar enzyme, what would be the predicted effect of applying Viagra to aurea mutant tomato leaves regarding de-etiolation?

  • A: It would lead to a more complete de-etiolation response.
  • B: It would have no effect on de-etiolation, as *aurea* mutants lack the cGMP pathway.
  • C: It would inhibit de-etiolation further, making the leaves even paler.
  • D: It would cause a normal de-etiolation, indistinguishable from wild-type plants.

Explanation

The text mentions that 'the injection of cGMP into aurea tomato leaf cells, for example, induces only a partial de-etiolation response.' If Viagra inhibits the enzyme that breaks down cGMP, it would lead to higher levels of cGMP. Higher cGMP levels would then enhance the existing partial de-etiolation pathway in aurea mutants, leading to a more complete response.