Question

21/40
which process requires atp?
active transport by na+/k+ pump
diffusion of na+
opening of voltage-gated na+ channels
diffusion of k+

Explanation:

To determine which process requires ATP, we analyze each option:

• Active transport by \( \text{Na}^+/\text{K}^+ \) pump: Active transport moves substances against their concentration gradient and requires energy (ATP). The \( \text{Na}^+/\text{K}^+ \) pump uses ATP to pump 3 \( \text{Na}^+ \) out and 2 \( \text{K}^+ \) into the cell.
• Diffusion of \( \text{Na}^+ \): Diffusion is passive (moves down concentration gradient) and does not require ATP.
• Opening of voltage - gated \( \text{Na}^+ \) channels: This is a passive process (ion movement through channels down gradient) and does not need ATP for channel opening (the voltage change triggers it, not ATP hydrolysis).
• Diffusion of \( \text{K}^+ \): Diffusion is passive, so no ATP is required.

So the process that requires ATP is active transport by the \( \text{Na}^+/\text{K}^+ \) pump.

Answer:

A. Active transport by \( \text{Na}^+/\text{K}^+ \) pump