Which statement about active transport is true?

Which statement about active transport is true?

• A. It moves substances with their gradient without energy.
• B. It occurs only in the nucleus.
• C. It moves substances against their concentration gradient using energy (ATP).
• D. It does not require carrier proteins.

Answer: (C)

Active transport uses energy to move substances against their concentration gradient through carrier proteins in the membrane. This energy input, often from ATP, powers pumps that change shape to move ions or molecules from a lower concentration to a higher one, which is essential for maintaining cell ion balances and nutrient uptake. That’s why the statement that best fits is that it moves substances against their gradient using energy (ATP). In contrast, moving with a gradient without energy describes passive transport like diffusion, active transport isn’t limited to the nucleus, and it relies on carrier proteins (pumps) rather than occurring without them.

Active transport uses energy to move substances against their concentration gradient through carrier proteins in the membrane. This energy input, often from ATP, powers pumps that change shape to move ions or molecules from a lower concentration to a higher one, which is essential for maintaining cell ion balances and nutrient uptake. That’s why the statement that best fits is that it moves substances against their gradient using energy (ATP). In contrast, moving with a gradient without energy describes passive transport like diffusion, active transport isn’t limited to the nucleus, and it relies on carrier proteins (pumps) rather than occurring without them.