Final answer:
Active transport is the energy-requiring process of pumping molecules and ions across membranes against a concentration gradient using ATP. Protein pumps are an example of active transport.
Step-by-step explanation:
Active transport is the energy-requiring process of pumping molecules and ions across membranes against a concentration gradient. It requires ATP, or adenosine triphosphate, for energy. Protein pumps are one example of active transport, as they use ATP to move molecules or ions from an area of low concentration to an area of high concentration. Active transport also works against the natural flow of diffusion, so it is considered uphill transport.