Final answer:
G-protein-coupled receptors involve a multi-step process to activate intracellular pathways, while ligand-gated receptors are ion channels that respond directly and quickly to ligand binding by allowing ion passage through the membrane.
Step-by-step explanation:
The major difference between reception based on G-protein-coupled receptors (GPCRs) and reception based on ligand-gated receptors lies in their mechanisms of action and location. GPCRs interact with an intracellular G-protein, which can then affect an ion channel or an enzyme within the cell membrane. This is a multi-step process where the ligand binding to the GPCR leads to G-protein activation followed by subsequent intracellular signaling events. Conversely, ligand-gated receptors are a type of ion channel that opens to allow ions such as Na+ and K+ to pass through the plasma membrane in direct response to ligand binding, leading to an immediate change in the cell's membrane potential.
G-protein-coupled receptors have seven transmembrane domains with a specific extracellular domain for ligand binding and a G-protein-binding site on the cytoplasmic side. This enables cell signaling through a series of cyclic events, including GDP and GTP exchange, activation of other proteins, and eventual deactivation and reassembly of the G-protein for a new cycle. This complex signaling process can regulate various physiological responses, such as vision, taste, and immune responses. In contrast, ligand-gated receptors provide a more straightforward and faster response to the presence of a signaling molecule by directly controlling ion flow across the membrane.