[Campbell Biology P.190] Which of the following is a key difference between active transport... | Practice Question
Which of the following is a key difference between active transport and facilitated diffusion?
A: Active transport moves substances down their concentration gradient, while facilitated diffusion moves them against.
B: Active transport always requires direct ATP hydrolysis, while facilitated diffusion does not.
C: Active transport requires energy and moves solutes against their concentration gradient, whereas facilitated diffusion does not require energy and moves solutes down their concentration gradient.
D: Only facilitated diffusion involves membrane proteins, while active transport does not.
Explanation
Active transport is characterized by its requirement for energy often from ATP to move substances against their concentration gradient. In contrast, facilitated diffusion is a type of passive transport that does not require metabolic energy and moves substances down their concentration gradient with the help of transport proteins.