active transport

Active transport is a biological process in which cells move molecules across the cell membrane against their concentration gradient, using energy typically derived from ATP. This mechanism allows the cell to maintain essential concentrations of ions and nutrients that are necessary for various cellular functions. Unlike passive transport, which relies on diffusion, active transport requires specific transport proteins and energy input to move substances from areas of lower concentration to areas of higher concentration. Common examples include the sodium-potassium pump and proton pumps, which are vital for maintaining cellular homeostasis and enabling processes such as nerve impulse transmission and muscle contraction.