Question

active transport and facilitated diffusion are different because active transport ______.

• is resistant to the effects of denaturation
• uses atp to power the movement of materials across a membrane
• only moves solute molecules with a concentration gradient
• uses a protein to move materials across a membrane

Explanation:

1. Analyze each option:

• Option 1: Active transport involves proteins (like pumps) which can be denatured, so it's not resistant to denaturation. Eliminate this.
• Option 2: Active transport requires energy (ATP) to move substances against their concentration gradient. Facilitated diffusion is passive (no ATP use). This matches the key difference.
• Option 3: Active transport moves solutes against the concentration gradient, while facilitated diffusion moves with it. So this is incorrect.
• Option 4: Both active transport (e.g., pumps) and facilitated diffusion (e.g., channel/carrier proteins) use proteins. So this is not a distinguishing factor.

Answer:

B. uses ATP to power the movement of materials across a membrane