AP BIOLOGY

Detailed explanation-1: -First step in the G protein mediated signaling cascade is binding of an agonist/ligand to GPCRs, so these molecules form an important part of this pathway.

Detailed explanation-2: -Reception – This is the first stage of the cell signaling pathway. During this stage, a signaling molecule binds to a receptor protein located on the surface of the cell or inside the cell.

Detailed explanation-3: -When a signaling molecule binds to its receptor, it alters the shape or activity of the receptor, triggering a change inside of the cell. Signaling molecules are often called ligands, a general term for molecules that bind specifically to other molecules (such as receptors).

Detailed explanation-4: -A ligand binds to a receptor, leading indirectly to activation of adenylyl cyclase, which converts ATP to cAMP. cAMP binds to protein kinase A and activates it, allowing PKA to phosphorylate downstream factors to produce a cellular response.