Question

which of the following proteins bind to molecules or ions that change their conformation and carry them across the membrane?
a channel proteins
b gated channel proteins
c carrier proteins

Explanation:

• Option a: Channel proteins form pores for molecules/ions to pass through via facilitated diffusion, without binding to them or changing conformation.
• Option b: Gated channel proteins open/close in response to stimuli (e.g., voltage, ligands) but still function as pores, not by binding and changing conformation to carry substances.
• Option c: Carrier proteins bind to specific molecules/ions, undergo a conformational change, and transport the substance across the membrane (e.g., glucose transporters). This matches the description in the question.

Answer:

c. carrier proteins