Which of the following is an example of a first or second messenger?
A) peptide hormone
B) G protein-coupled receptor
C) protein kinase
D) cyclic nucleotide phosphodiesterase

Question

Quizplus · Accepted Answer

Peptide hormone is an example of a first messenger as it directly binds to a receptor on the cell surface and initiates signal transduction. G protein-coupled receptor, protein kinase, and cyclic nucleotide phosphodiesterase are all components of the signal transduction pathway but are not first or second messengers themselves.

Which of the Following Is an Example of a First