AP BIOLOGY

Detailed explanation-1: -Active transport requires energy for the process by transporting molecules against a concentration or electrochemical gradient.

Detailed explanation-2: -Active transport is used by cells to accumulate needed molecules such as glucose and amino acids. Active transport powered by adenosine triphosphate (ATP) is known as primary active transport. Transport that uses an electrochemical gradient is called secondary transport.

Detailed explanation-3: -Primary active transport directly uses a source of chemical energy (e.g., ATP) to move molecules across a membrane against their gradient.

Detailed explanation-4: -Movement Across a Membrane and Energy Passive mechanisms like diffusion use no energy, while active transport requires energy to get done.