Carrier mediated active transport
Carrier mediated active transport requires both energy (ATP) and the assistance of a transport protein, called pump.
Each pump only transports particular substances, so cells Can control what is absorbed and what is expelled. Pumps work in a specific Direction –the substance can only enter the
pump on one side and can only exit on the other side. Energy Is used to “pump” molecules across cell membranes against their concentration Gradients.
Vesicular active transport
Vesicular active transport is an energy-requiring Mechanism whereby large molecules move into or out of cells by an enclosed vesicle.
• Endocytosis moves substances from the Extracellular to the intracellular environment; a portion of the cell membrane Surrounds an extracellular particle, enclosing it in a vesicle.
o Phagocytosis (“cell eating”)àthe Process by which solid substances are ingested. Vesicle called phagosome.
o Pinocytosis (“cell drinking”)àthe Process by which liquids with dissolved substances are ingested.
• Exocytosis is the process by which large Substances exit the cell by packaging them in vesicles that fuse with the Plasma membrane, expelling their contents into the extracellular environment.