Definitions for "Active Transport"
The movement of molecules across a cell membrane from a region of lower concentration to a region of higher concentration. Because active transport involves moving the molecule against the natural flow of the concentration gradient, the process requires energy.
The process of moving molecules across a membrane, generally from an area of lower concentration to an area of higher concentration which is unfavorable and thus requires energy input.
The transport of a substance across a biological membrane against a concentration gradient—that is, from a region of low concentration (of that substance) to a region of high concentration. Active transport requires the expenditure of energy and is a saturable process. (Contrast with facilitated diffusion, free diffusion; see primary active transport, secondary active transport.)