試題詳解

22. Membrane transport describes different ways for molecules to across the cell membrane. Which of the following statements is   correct   regarding membrane transport?

(1) In facilitated diffusion, molecules move across the membrane through a protein channel or carrier down their concentration gradient.

(2) The presence of aquaporins in the cell membrane facilitates the active transport of water molecules into and out of the cell.

(3) Secondary active transport does not directly utilize ATP but relies on the electrochemical gradient created by primary active transport.
(A) 3 only
(B) 1 and 2
(C) 1 and 3
(D) 2 and 3
(E) All of above are correct.