Active Transport • Defined: Molecules move from a LOW to a HIGH concentration • ATP energy needed to fight diffusion – ATP = Adenosine Triphosphate • ATP activates pumps (see animation) Active Transport Video Contractile vacuole of a Paramecium As water enters this cell by diffusion, it is immediately pumped out to prevent bursting Endocytosis • Endocytosis: Process in which the plasma membrane takes in substances (2 types) – 1) Phagocytosis: when a cell engulfs a solid particle – 2) Pinocytosis: when a cell engulfs a liquid particle • Unfortunately, viruses can also enter our cells this way Endocytosis & the lysosome The bacteria is engulfed by phagocytosis The bacteria is placed inside a lysosome are destroyed Exocytosis • Defined: Process when substances are expelled from the cell • Proteins, nutrients, and waste exit by exocytosis • Vesicle carry & release objects through the plasma membrane Review 1) How are active and passive transport different? 2) Which molecule powers active transport? 3) How are endo- and exocytosis similar? Different? 4) Which cell part controls active transport?