Which of the following statements correctly describes a similarity and a difference between facilitated diffusion and active transport?

• A. Both require a protein carrier, but only active transport requires energy.
• B. Both are forms of passive transport, but only active transport requires a protein carrier.
• C. Both require energy, but only facilitated diffusion uses a protein carrier.
• D. Both involve movement against the concentration gradient, but only facilitated diffusion requires energy.

Answer: (A)

Verified step by step guidance

1. Identify the key characteristics of facilitated diffusion: it is a passive transport process that does not require energy and involves the movement of molecules across a cell membrane through a protein carrier, following the concentration gradient.
2. Identify the key characteristics of active transport: it is an active process that requires energy (usually in the form of ATP) to move molecules against their concentration gradient, also using a protein carrier.
3. Compare the two processes: both facilitated diffusion and active transport involve the use of protein carriers to transport molecules across the cell membrane.
4. Highlight the main difference: facilitated diffusion does not require energy as it moves molecules along the concentration gradient, whereas active transport requires energy to move molecules against the concentration gradient.
5. Conclude that the correct statement is: 'Both require a protein carrier, but only active transport requires energy.' This statement accurately describes the similarity and difference between facilitated diffusion and active transport.