Which definition describes a receptor?

Question

1. A cell component to which a drug binds in a dose-dependent manner
2. Present only in the drug's target tissue
3. Required to drug action
4. Analogous to the "key" in the lock-and-key model of drug–receptor interaction

Answer 1

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 drug–receptor interaction is incorrect because a receptor is analogous to the "lock" in the lock-and-key model of drug–receptor 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 drug—receptor interaction is incorrect because a receptor is analogous to the "lock" in the lock-and-key model of drug—receptor interaction.