ATP can be used to power which of the following processes?

• A. Movement of water by osmosis
• B. Facilitated diffusion of glucose
• C. Active transport of ions across a membrane
• D. Passive diffusion of oxygen into a cell

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the role of ATP in cellular processes. ATP (adenosine triphosphate) is the primary energy currency of the cell, used to power energy-requiring processes such as active transport, muscle contraction, and chemical reactions.
2. Step 2: Review the definitions of the processes listed in the problem. Osmosis is the passive movement of water across a membrane, facilitated diffusion is the passive transport of molecules like glucose via protein channels, active transport requires energy (ATP) to move ions or molecules against their concentration gradient, and passive diffusion is the movement of molecules like oxygen down their concentration gradient without energy input.
3. Step 3: Identify which processes require energy input. Among the options, active transport of ions across a membrane is the only process that requires ATP because it moves substances against their concentration gradient.
4. Step 4: Eliminate processes that do not require ATP. Osmosis, facilitated diffusion, and passive diffusion are all passive processes that occur without the need for energy input from ATP.
5. Step 5: Conclude that ATP is specifically used to power active transport of ions across a membrane, as this process requires energy to move substances against their natural concentration gradient.