True or false. A receptor may act as a signal. Explain and justify your answer.

Question

True or false. A receptor may act as a signal. Explain and justify your answer.

Answer 1

This is a somewhat misleading question, and would depend on the grade you are in. The receptor actually is NOT a signal, but rather is a transducer of some other signal. This may be a little more advanced, but that would be correct. In introductory and beginning courses, one may describe a receptor as a signal, but it's really reacting to some other signal that activates the receptor or inhibits it.

Explanation: A receptor is a protein and reacts to some ligand (a substance that binds to the receptor), and then causes some reaction or response to occur. The ligand is the first messenger, the receptor is a transducer or mediator, and then there can be a second messenger. So, the first and second messengers are considered as signals, and the receptor is considered as a mediator of the signal.