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15 Cards in this Set
- Front
- Back
what is a cell membrane |
mosaic of phospholipids and proteins in which the individual molecules are free to move about within the layers |
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what gets through |
SIZE (small molecules) POLARITY (soluble in lipids) IONS (impermeable to ions) |
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what cannot get through |
too big soluble in water |
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Facilitated diffusion |
Passive diffusion through selective protein channels in membranes |
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Active Transport |
Movement of substances across membranes that require the expenditure of energy; occurs through protein channels. Gets essential nutrients in and wastes out |
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Channel Proteins |
Form a hole straight through membrane, usually for small molecules |
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Carrier Proteins |
In one end out the other (revolving door) Uses ATP to open door Changes shape |
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Vesicular Transport |
Transport vesicles play a central role in traffic of molecules between membranes |
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Endocytosis |
Occurs by infolding of the plasma membrane, which then forms vesicles which become detached and enter the cytoplasm. |
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Exocytosis |
Reverse process of endocytosis. Exports products, such as proteins, from the cell to elsewhere in the body or outside it. |
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Enzymes |
Proteins. Organic catalysts that speed up biochemical reaction, but enzyme remains unchanged. |
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Catabolic Reactions |
Break down complex molecules into simpler ones and involve a net release of energy |
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Anabolic Reactions |
Involve a net use of energy and build more complex molecules and structures from simpler ones. |
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Phagocytosis |
Where endocytosis involves the intake of solid particles eg. Feeding in amoeba |
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Pinocytosis |
Where endocytosis involves the intake of liquid material eg. uptake in protozoa |