By which of the following mechanisms can a cell transport a substance from a lower to a higher concentration?
A) aquaporins
B) extracellular enzymes
C) facilitated diffusion
D) active transport
E) simple diffusion

Question

Quizplus · Accepted Answer

Active transport is the only mechanism listed that can transport a substance from a lower to a higher concentration. This process requires the input of energy, typically in the form of ATP, to move substances against their concentration gradient. Aquaporins facilitate the transport of water, but do not move substances against a concentration gradient. Extracellular enzymes are involved in breaking down substances outside of the cell, and do not transport molecules themselves. Facilitated diffusion and simple diffusion both move substances down their concentration gradient from higher to lower concentrations.

By Which of the Following Mechanisms Can a Cell Transport