P-glycoprotein is an example of carrier mediated protein used in facilitated diffusion.

• A. True
• B. False
• C. Not sure
• D. Depends on the drug

Answer: (B)

Understanding the difference between facilitated diffusion and active transport is key. P-glycoprotein is an efflux transporter in cell membranes that uses energy from ATP hydrolysis to pump a wide range of drugs out of cells. This energy-consuming process is active transport, not facilitated diffusion, which is carrier-mediated but occurs passively down a concentration gradient without energy input. Because P-glycoprotein actively expels drugs rather than simply helping them move down a gradient, the statement is false. Remember that facilitated diffusion is passive; P-glycoprotein is an active efflux transporter and a major player in reducing drug absorption and in multidrug resistance.