what is active transport

Active transport is a process in cellular biology that involves the movement of molecules or ions across a cell membrane from a region of lower concentration to a region of higher concentration, against the concentration gradient. This process requires cellular energy to achieve the movement and is essential for various physiological processes, such as nutrient uptake, hormone secretion, and nerve impulse transmission. There are two types of active transport: primary active transport, which uses adenosine triphosphate (ATP), and secondary active transport, which uses an electrochemical gradient as an energy source. Examples of active transport include the transportation of sodium out of the cell and potassium into the cell by the sodium-potassium pump, as well as the movement of Ca2+ ions out of cardiac muscle cells and the transportation of amino acids across the intestinal lining in the human gut