Question

facilitated diffusion is a protein-facilitated movement of solutes across a membrane from an area of higher concentration to an area of lower concentration. which of the terms best describes facilitated diffusion?
○ osmosis
○ ion pump
○ active transport
○ passive transport

Explanation:

1. Analyze each option:

• Osmosis: Movement of water across a semi - permeable membrane, not solutes in general, so it's not the answer.
• Ion pump: Requires energy (ATP) to move ions against concentration gradient, which is active transport, not related to facilitated diffusion.
• Active transport: Moves substances from low to high concentration (against gradient) and requires energy. Facilitated diffusion moves from high to low, so not active transport.
• Passive transport: Moves substances from high to low concentration (down gradient) without energy. Facilitated diffusion (protein - facilitated, high to low) fits this as it doesn't require energy and moves down concentration gradient.

Answer:

D. passive transport