43. Which of the following statements concerning the action of G proteins on adenylate cyclase is true? I. G proteins always serve to activate adenylate cyclase. II. G proteins always serve to inhibit adenylate cyclase. III. Some G proteins activate adenylate cyclase, while others inhibit it. IV. G proteins do not act on adenylate cyclase at all. 9

Some G proteins activate adenylate cyclase, while others inhibit it.

Explanation:

G proteins helps in the signal transduction process that transfer message in the body. GPCRs (G-protein-coupled receptors) are located on the surface membrane of the cell.

The G protein can activates the protein or might deactivate the proteins that helps in the adenylate cyclase. The particular phosphorylation and dephosphorylation process at different sites by the G proteins can result in activation and inactivation of adenylate cyclase.

Thus, the correct answer is option (C).

law of conservation of matter

conduction is the transfer of thermal energy (heat in transfer) due to collisions between the molecules in the object. collisions between adjacent atoms and molecules transfer kinetic energy from the warmer to the cooler object. the objects must be in physical contact.