Question

select the true statements. facilitated diffusion is a form of active transport. facilitated diffusion makes it possible for charged molecules to cross the cell membrane without being repelled by phospholipid tails. in facilitated diffusion, molecules move down their concentration gradient to reach equilibrium. once equilibrium is reached via facilitated diffusion, molecules stop moving completely.

Explanation:

• Facilitated diffusion is a form of passive transport (not active transport), so the first statement is false.
• Charged molecules cannot easily cross the cell membrane due to the hydrophobic phospholipid tails. Facilitated diffusion uses transport proteins, allowing charged molecules to cross without being repelled, so the second statement is true.
• In facilitated diffusion, like all diffusion processes, molecules move down their concentration gradient (from higher to lower concentration) until equilibrium is reached, so the third statement is true.
• At equilibrium, molecules continue to move back and forth across the membrane, just at an equal rate in both directions (net movement is zero), so the fourth statement is false.

Answer:

• "Facilitated diffusion makes it possible for charged molecules to cross the cell membrane without being repelled by phospholipid tails."
• "In facilitated diffusion, molecules move down their concentration gradient to reach equilibrium."