Which of the Following Membrane Activities Require Energy from ATP

Question

Which of the following membrane activities require energy from ATP hydrolysis?
A) facilitated diffusion of chloride ions across the membrane through a chloride channel
B) movement of water into a cell
C) Na⁺ ions moving out of a mammalian cell bathed in physiological saline
D) movement of glucose molecules into a bacterial cell from a medium containing a higher concentration of glucose than inside the cell
E) movement of carbon dioxide out of a paramecium

Accepted Answer

Moving the Na⁺ ions against their concentration gradient requires energy in the form of ATP hydrolysis. A is incorrect because facilitated diffusion does not require energy from ATP hydrolysis. B is incorrect because movement of water into a cell by osmosis does not require energy. D is incorrect because movement of glucose down its concentration gradient does not require energy from ATP hydrolysis. E is incorrect because movement of carbon dioxide across the membrane occurs by simple diffusion and does not require energy from ATP hydrolysis.