The three methods of active transport of particles are:

1. Protein pumps: Energy from ATP is used to pump small molecules and ions across the cell membrane. Active transport proteins change shape during the process, binding substances on one side of the membrane, and releasing them on the other.
2. Endocytosis: The membrane forms a pocket around a particle. The pocket then breaks loose from the outer portion of the cell membrane and forms a vesicle within the cytoplasm.
3. Exocytosis: The membrane of a vesicle surrounds the material then fuses with the cell membrane. The contents are forced out of the cell.