Ligand-Induced Conformational Change in Receptors

Steps:

• Recall that cell signaling involves ligands binding to specific receptors on or in cells.
• Evaluate each option against basic principles of receptor-ligand interactions.
• Identify that binding typically alters receptor shape to trigger signaling.
• Confirm the option matching this mechanism as correct.

Why B is correct:

• Ligand binding induces a conformational change in the receptor, activating intracellular signaling pathways, as defined in receptor theory.

Why the others are wrong:

• A: Receptors are specific; each recognizes only certain ligands, not all in the body.
• C: Most receptors are on the cell surface or membrane; intracellular receptors exist but are not universal.
• D: Ligands are produced by specific cells, not all cells in the body.

Final answer: B