What term describes the movement of materials through a cell membrane using energy?

The term that describes the movement of materials through a cell membrane using energy is active transport. This process is essential for cells to transport substances against their concentration gradient, from an area of lower concentration to an area of higher concentration. Active transport requires energy, usually in the form of ATP, because it is moving substances in the opposite direction of what would occur naturally through passive mechanisms.

In contrast, passive transport refers to the movement of substances across a cell membrane without the use of energy, occurring down their concentration gradient. Diffusion is a type of passive transport where molecules spread from areas of high concentration to areas of low concentration until equilibrium is reached. Facilitated diffusion also doesn't require energy; instead, it uses protein channels to transport molecules across the membrane, but this process still moves substances down their concentration gradient. Understanding these distinctions highlights why active transport is the only mechanism that specifically involves energy usage for moving materials into or out of the cell.