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

Answer 1

The movement of Na+ ions out of a mammalian cell uses active transport, which requires ATP hydrolysis, while the other options (A, B, D, and E) are passive transport processes that do not require ATP.

Step-by-step explanation:

The membrane activities that require energy from ATP hydrolysis are typically referred to as active transport. Of the options listed, Na+ ions moving out of a mammalian cell bathed in physiological saline is an example of active transport, which uses ATP to move Na+ ions against their concentration gradient, a process known as the sodium-potassium pump.

Facilitated diffusion of chloride ions (option A), movement of water (option B), movement of glucose molecules into a bacterial cell (option D), and movement of carbon dioxide out of a paramecium (option E) are all examples of passive transport. During passive transport, substances move down their concentration gradient through the membrane without the need for ATP, using mechanisms such as diffusion, osmosis, or facilitated diffusion through specific protein channels or carriers.