In primary active transport, energy is directly used to move molecules. The energy source is almost always . The protein responsible for this process is a "pump" that hydrolyzes ATP (breaks it down into ADP + phosphate) to change its shape and shuttle the molecule across the membrane.
The driving ion and the transported molecule move in the across the membrane. kinds of active transport
: The cell membrane folds inward to form a pocket, engulfing external material and bringing it inside. In primary active transport, energy is directly used