Consider this pathway: epinephrine → g protein-coupled receptor → g protein → adenylyl cyclase → camp. identify the second messenger.
a. camp
b. g protein
c. gtp
d. adenylyl cyclase

a. cAMP

Explanation:

Secondary messengers are signaling molecules which are present intracellularly and play a great role in amplification of a signal during signal transduction pathway.

cAMP, DAG and IP3 are common secondary messengers in GPCR signalling. GPCR are largest family of cell surface receptors which are associated with various functions like control of blood vessel dialation, interstitial epithelial cells, glycogen breakdown, inflammation, photoisomerization reaction etc.