All the three subunits alpha, beta and gamma should bind to each other for G proteins to act
C
G proteins act as inhibitory and excitatory because of difference in alpha subunit
D
G protein is bound to GTP in resting state
High-Yield Explanation
Alpha subunit of GPCR has got adenyl cyclase stimulation of inhibition of adenyl cyclase- responsible for actions of GPCR Pg.no 46 KD TRIPATHI SEVENTH EDITION