Which models describe theories of drug-receptor interaction?

• A. Lock and Key model and induced fit model
• B. Induced fit model
• C. Lock and Key model
• D. Allosteric model

Answer: (A)

Two classic ways to envision drug–receptor binding are the lock-and-key idea and the induced-fit idea. The lock-and-key model imagines a rigid fit where the drug’s shape matches the receptor’s binding site exactly, so binding occurs only if the shapes align perfectly. The induced-fit model allows some flexibility: when the drug binds, the receptor (and sometimes the drug) adjusts its shape to create a snug, stable interaction. Together, these perspectives cover how drugs recognize and bind receptors—either through an initially complementary fit or by conformational changes that optimize binding. The allosteric model describes modulation via a different site that alters receptor activity, which is a distinct mechanism from the classic binding theories, so it’s not required to describe the primary drug–receptor interaction here.