AP BIOLOGY

Detailed explanation-1: -To move substances against a concentration or electrochemical gradient, a cell must use energy. Active transport mechanisms do just this, expending energy (often in the form of ATP) to maintain the right concentrations of ions and molecules in living cells.

Detailed explanation-2: -During active transport, substances move against the concentration gradient, from an area of low concentration to an area of high concentration. This process is “active” because it requires the use of energy (usually in the form of ATP). It is the opposite of passive transport.

Detailed explanation-3: -Active transport is a kind of cellular transport in which substances like amino acids, glucose and ions are transported across cell membranes to a region that already has a high concentration of such substances.

Detailed explanation-4: -This spread of particles through random motion from an area of high concentration to an area of lower concentration is known as diffusion. This unequal distribution of molecules is called a concentration gradient.

Detailed explanation-5: -The energy necessary for active transport (against the concentration gradient of the transported substance) to occur comes from adenosine triphosphate (ATP) molecules. Adenosine triphosphate (ATP), energy-carrying molecule found in the cells of all living things.