When adenylyl cyclase is activated.
a. steroids are produced.
b. calcium ions are released from intracellular stores.
c. CAMP is formed.
d. CAMP is broken down.
e. protein kinases are metabolized.
The correct answer and explanation is :
The correct answer is c. cAMP is formed.
Explanation:
Adenylyl cyclase is an enzyme that plays a crucial role in cell signaling. It is typically activated by various signals, including hormones, neurotransmitters, or other signaling molecules. When adenylyl cyclase is activated, it catalyzes the conversion of ATP (adenosine triphosphate) into cyclic AMP (cAMP), a secondary messenger molecule that mediates many cellular responses.
- Activation of Adenylyl Cyclase: This process often begins when a ligand (such as a hormone like adrenaline or glucagon) binds to a G-protein-coupled receptor (GPCR) on the surface of a target cell. This receptor is coupled to a G protein that, when activated, stimulates adenylyl cyclase. The enzyme then converts ATP into cAMP.
- Role of cAMP: cAMP acts as a secondary messenger within the cell. It plays a central role in transducing signals from the cell surface to intracellular targets, amplifying the signal. cAMP activates protein kinase A (PKA), which then phosphorylates various target proteins, leading to a wide variety of cellular responses, including changes in gene expression, metabolism, ion transport, and cell growth.
- Why the other options are incorrect:
- a. Steroids are produced: Steroid production is not directly linked to adenylyl cyclase activation. Steroid hormones are synthesized from cholesterol and typically involve different signaling pathways.
- b. Calcium ions are released from intracellular stores: While calcium signaling is important in many cellular processes, the activation of adenylyl cyclase specifically leads to cAMP production, not calcium release.
- d. cAMP is broken down: This happens through the action of phosphodiesterases, which degrade cAMP into AMP, but this is not a direct result of adenylyl cyclase activation.
- e. Protein kinases are metabolized: Protein kinases, like PKA, are activated, not metabolized, by cAMP.
Thus, the primary function of activated adenylyl cyclase is the formation of cAMP, which then triggers various signaling cascades in the cell.