試題詳解

16. Hormone X produces its effect in its target cells via the cAMP second messenger system. Which of the following will produce the greatest effect in the cell?
(A) A molecule of cAMP applied to the extracellular fluid surrounding the cell.
(B) A molecule of cAMP injected into the cytoplasm of the cell.
(C) A molecule of hormone X applied to the extracellular fluid surrounding the cell.
(D) A molecule of hormone X injected into the cytoplasm of the cell.
(E) A molecule of activated, cAMP-dependent protein kinase injected into the cytoplasm of the cell.