Answer :
Final answer:
The two key second messenger pathways controlled by receptors via G proteins are the cAMP pathway and the Phosphoinositide (or calcium) pathway, each involving distinct molecules and mechanisms to transmit signals within the cell. So the correct option is: a. cAMP pathway
Explanation:
The 2 key second messenger pathways controlled by receptors via G proteins are the cAMP pathway and the Phosphoinositide (or calcium) pathway. The cAMP pathway involves the activation of adenylyl cyclase, which converts ATP to cAMP. cAMP then activates protein kinase A (PKA), leading to phosphorylation of target molecules and altering cell function. The Phosphoinositide pathway, on the other hand, involves the activation of phospholipase C (PLC), which then cleaves a membrane-bound phospholipid into diacylglycerol (DAG) and inositol triphosphate (IP3). DAG activates protein kinases, while IP3 induces the release of calcium ions from internal stores, further propagating the signal through additional phosphorylation events or direct effects on cellular processes.
