Which definition describes a receptor? 1. A cell component to which a drug binds in a ...

Correct Answer: 1

Rationale 1: A cell component to which a drug binds in a dose-dependent manner is a receptor.
Rationale 2: Present only in the drug's target tissue is incorrect because receptors are present not only in the drug's target tissue, but in many other tissues in the body. It often is drug effects at sites other than the target tissue that result in side effects.
Rationale 3: Required to drug action is incorrect because although most drugs act via receptor-mediated mechanisms, some drugs do not act at specific receptors.
Rationale 4: Analogous to the key in the lock-and-key model of drugreceptor interaction is incorrect because a receptor is analogous to the lock in the lock-and-key model of drugreceptor interaction.

Global Rationale: A cell component to which a drug binds in a dose-dependent manner is a receptor. Present only in the drug's target tissue is incorrect because receptors are present not only in the drug's target tissue, but in many other tissues in the body. It often is drug effects at sites other than the target tissue that result in side effects. Analogous to the key in the lock-and-key model of drugreceptor interaction is incorrect because a receptor is analogous to the lock in the lock-and-key model of drugreceptor interaction.