AP BIOLOGY

Detailed explanation-1: -Final answer: Active transport requires energy in the form of ATP.

Detailed explanation-2: -Another important example of active transport is the mitochondrial electron transport chain, which is based on reduction of NADH. It moves protons across the mitochondrial membrane from lower to higher concentration. This generates energy used to power life. Photosynthesis is also based on active 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: -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).

Detailed explanation-5: -Movement Across a Membrane and Energy Passive mechanisms like diffusion use no energy, while active transport requires energy to get done.