EVERYDAY SCIENCE

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: -Active transport requires energy for the process by transporting molecules against a concentration or electrochemical gradient.

Detailed explanation-3: -ATP is consumed for energy in processes including ion transport, muscle contraction, nerve impulse propagation, substrate phosphorylation, and chemical synthesis. These processes, as well as others, create a high demand for ATP.

Detailed explanation-4: -Primary active transport, also called direct active transport, directly uses chemical energy (such as from adenosine triphosphate or ATP in case of cell membrane) to transport all species of solutes across a membrane against their concentration gradient.