AS Biology - Active transport, Endocytosis and Exocytosis 

AS Biology - Cells topic. Explanation of Active transport, using carrier protein and the hydrolysis of ATP into ADP and inorganic phosphate. Endocytosis (phagocytosis and pinocytosis) and Exocytosis as methods of bulk transport that use ATP and incolve the fusion of vesicles with the cell surface membrane.