Cells that respond to peptide hormones usually do so through a sequence of biochemical reactions involving receptor and kinase activation. In order for cells to respond, it is necessary for first and second messengers to communicate. This is possible because ________.
A) peptide hormones always enter the cell membrane and elicit a response without assistance from other messengers
B) hormones alter cellular operations through stimulation of a gene directly
C) G protein acts as the link between first and second messengers
D) the hormone receptor complex moves into the cytoplasm as a unit
Answer: C