Which of the following is a difference between active transport and facilitated diffusion?

• A. Both active transport and facilitated diffusion require ATP to function.
• B. Facilitated diffusion moves substances against their concentration gradient, while active transport does not.
• C. Active transport only occurs in plant cells, while facilitated diffusion occurs in all cell types.
• D. Active transport requires energy, while facilitated diffusion does not.

Answer: (D)

Verified step by step guidance

1. Begin by understanding the basic definitions of active transport and facilitated diffusion. Active transport is the movement of molecules across a cell membrane from a region of lower concentration to a region of higher concentration, using energy, typically in the form of ATP. Facilitated diffusion, on the other hand, is the passive movement of molecules across the cell membrane via specific transport proteins, without the use of energy, moving from a region of higher concentration to a region of lower concentration.
2. Identify the key difference between the two processes. Active transport requires energy because it moves substances against their concentration gradient, which is energetically unfavorable. Facilitated diffusion does not require energy because it moves substances down their concentration gradient, which is energetically favorable.
3. Examine the options provided in the problem. The first option incorrectly states that both processes require ATP, which contradicts the definition of facilitated diffusion. The second option incorrectly describes facilitated diffusion as moving substances against their concentration gradient, which is actually a characteristic of active transport. The third option incorrectly limits active transport to plant cells, which is not true as active transport occurs in all cell types.
4. Focus on the correct statement: 'Active transport requires energy, while facilitated diffusion does not.' This aligns with the definitions and characteristics of the two processes.
5. Conclude by reinforcing the understanding that the requirement of energy is the fundamental difference between active transport and facilitated diffusion, with active transport needing energy to move substances against their concentration gradient, while facilitated diffusion does not require energy and moves substances down their concentration gradient.