Question

multiple choice question
which of the following uses atp to move substances across a membrane?

primary active transport
passive diffusion
osmosis
facilitated diffusion

Explanation:

• Passive diffusion: Moves substances down concentration gradient without energy (including ATP), so incorrect.
• Osmosis: Is the diffusion of water, also passive and no ATP use, incorrect.
• Facilitated diffusion: Uses transport proteins but still moves down gradient, no ATP, incorrect.
• Primary active transport: Directly uses ATP to move substances against their concentration gradient, so this is correct.

Answer:

A. Primary active transport