Section 5-2 Notes
Active Transport: movement of molecules going up from low concentration to high
concentration; requires energy.
Cell Membrane Pumps
 Ion channels and carrier proteins also assist in active transport.
 Carrier proteins are called pumps when they are assisting in active transport.
 Sodium potassium pump: active transport in animal cells involving carrier protein;
transports NA ions and K ions.
 Sodium potassium pump causes cell membrane to be positively charged in the outside
and negatively charged in the inside.
Movement in Vesicles
 Endocytosis and Exocytosis: transport mechanisms/ process which is used to
transport big molecules in and out of the cell membrane.
 Endocytosis: process by which cells ingest external fluid, macromolecules, and large
particles, including cells. Two main types of endocytosis (based on content):
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Pinocytosis: transport of solutes or fluids
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Phagocytosis: transport of large particles or whole cells (Phagocytes (unicellular))
 Exocytosis: process by which a substance is released from the cell through a vesicle
that transports the substance to the cell surface and then fuses with the membrane
to let the substance out of the cell. (reverse of endocytosis)
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Vesicles release their contents into the cell’s external environment.
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Cells use exocytosis to release large molecules (proteins, wastes, or toxins that
may damage the cell)