Which sequence of events correctly describes the mechanism of a carrier protein in facilitated diffusion?

• A. Carrier protein forms a tunnel, solute passes through, carrier returns to original shape.
• B. Solute diffuses through lipid bilayer, carrier protein assists in movement.
• C. Solute binds to carrier protein, carrier undergoes conformational change, solute is released on the other side of the membrane.
• D. Carrier protein uses ATP, solute binds, solute is transported across the membrane.

Answer: (C)