Final answer:
Cell-surface receptors are integral proteins located on the surface of a cell that bind to external ligand molecules. They are involved in signal transduction, converting extracellular signals into intracellular signals. There are different categories of cell-surface receptors, including enzyme-linked receptors, ion channel-linked receptors, and G-protein-linked receptors.
Step-by-step explanation:
Cell-surface receptors are integral proteins that bind to external ligand molecules. They are located on the surface of a cell and span the plasma membrane. These receptors are involved in signal transduction, where an extracellular signal is converted into an intracellular signal. The three general categories of cell-surface receptors are enzyme-linked receptors, ion channel-linked receptors, and G-protein-linked receptors.
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