What are the two primary functions of receptors?

What are the two primary functions of receptors?

• A. Binding to enzymes and catalyzing reactions.
• B. Sensing the ligand and transmitting the message (signal transduction).
• C. Generating electrical currents and pumping ions.
• D. Degrading ligands and recycling receptors.

Answer: (B)

Receptors are specialized proteins whose main job is to recognize specific signaling molecules (ligands) and then convert that binding into a cellular response. The recognition step ensures the cell responds to the right signal, and the transduction step translates that extracellular signal into an intracellular action—often through conformational changes that activate second messenger pathways, kinases, or ion channels. The result is a controlled cellular response to the external signal. The other ideas—acting as enzymes to catalyze reactions, generating electrical currents, or degrading ligands and recycling receptors—describe activities that aren’t the defining roles of receptors in the signaling sense.

Receptors are specialized proteins whose main job is to recognize specific signaling molecules (ligands) and then convert that binding into a cellular response. The recognition step ensures the cell responds to the right signal, and the transduction step translates that extracellular signal into an intracellular action—often through conformational changes that activate second messenger pathways, kinases, or ion channels. The result is a controlled cellular response to the external signal. The other ideas—acting as enzymes to catalyze reactions, generating electrical currents, or degrading ligands and recycling receptors—describe activities that aren’t the defining roles of receptors in the signaling sense.