Which term describes a molecule that blocks receptor activation?

Which term describes a molecule that blocks receptor activation?

• A. Agonist
• B. Antagonist
• C. Partial agonist
• D. Inverse agonist

Answer: (B)

An antagonist is a molecule that blocks receptor activation. It binds to the receptor without producing its own activating signal, preventing an agonist from triggering a response. If it binds at the same site as the agonist, it can be overcome by more agonist (competitive antagonism). In contrast, a partial agonist still activates the receptor, just not as fully, and an inverse agonist reduces baseline receptor activity rather than merely blocking activation.

An antagonist is a molecule that blocks receptor activation. It binds to the receptor without producing its own activating signal, preventing an agonist from triggering a response. If it binds at the same site as the agonist, it can be overcome by more agonist (competitive antagonism). In contrast, a partial agonist still activates the receptor, just not as fully, and an inverse agonist reduces baseline receptor activity rather than merely blocking activation.