AP BIOLOGY

Detailed explanation-1: -Active transport is an energy-driven process where membrane proteins transport molecules across cells, mainly classified as either primary or secondary, based on how energy is coupled to fuel these mechanisms.

Detailed explanation-2: -In active transport, substances move against a concentration gradient across a cell membrane. Hence energy is required. The energy available in the body in the form of ATP is used to move this substance across the cell membrane.

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.