Drug Action Exam 1 Practice Test

Drug-receptor interactions are dynamic; the induced fit idea recognizes that the receptor binding site can flex and change shape to snugly accommodate the drug. This flexibility helps explain how slight changes in a drug’s structure can dramatically affect binding and how receptors can adapt to optimize contact with the ligand, often triggering the right conformational change to initiate signaling. The rigid lock-and-key view is too limited because it treats the receptor as an immutable shape, whereas real receptors are capable of rearranging to improve binding and function. Receptors do change shape upon binding, which is why “never change shape” isn’t accurate. Binding typically occurs at orthosteric (active) sites, though allosteric sites also exist and can modulate activity, so saying binding happens only at allosteric sites isn’t correct.