The cell surface receptors that can act only indirectly on plasma membrane-bound enzymes or ion channels are called G Protein.
What is G-Protein Coupled Receptor?
G proteins are trimers made up of three distinct subunits that activate adenylyl cyclase. Alpha, beta, and gamma subunits are the names of these.
Gs is the name of the nucleotide-binding site on the alpha subunit. Adenylyl cyclase is activated when GTP binds to Gs, activating it in turn. When GDP binds to the nucleotide-binding site of G-protein, it becomes inactive.
When a signaling molecule like adrenaline binds, it makes it easier for GTP to replace the bound GDP and change the Gs into its active form. The beta and gamma Gs subunits separate from the alpha subunit as Gs is activated.
Adenylyl cyclase is then activated by the Gs once it has bound GTP and its alpha subunit.
Hence, the correct answer is G protein.
Learn more about G protein here,
brainly.com/question/13857308
# SPJ4