LIFE SCIENCE

Detailed explanation-1: -It involves using energy (usually ATP) to directly pump a solute across a membrane against its electrochemical gradient. The most studied example of primary active transport is the plasma membrane Na+, K+-ATPase discussed below (Chapter 19, Section 4.2).

Detailed explanation-2: -The energy for active transport comes from the energy-carrying molecule called ATP (adenosine triphosphate). Active transport may also require transport proteins, such as carrier proteins, which are embedded in the plasma membrane.

Detailed explanation-3: -The movement of molecules across a membrane without the input of energy is known as passive transport. When energy (ATP) is needed, the movement is known as active transport. Active transport moves molecules against their concentration gradient, from an area of low concentration to an area of high concentration.