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6 Cards in this Set
- Front
- Back
- 3rd side (hint)
Why are cell membranes asymmetrical?
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The "inside" and "outside" faces are different. Outside has molecules such as phosphatidylcholine, sphingomyelin, sugars, cholesterol. The inside, townard the cytosol, has phosphatidyl-serine, -inositol, -ethaolamine, cholesteroll. Proteins placed sometimes at random
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inside vs outside
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What is the cell cortex and what is its function?
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Network of actin filaments & associated proteins. Functions as support for the plasma membrane. Spectrin in the cortex cross-links membrane proteins
& provides strength. |
support
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Why is it crucial for cell membranes to maintain different internal and external ion concentrations?
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Ion channels: ions move down electrochemical gradient. the tendency of an electrically charged solute, such as K+, to move across the membrane is decided by the difference in ion concentrations on either side of membrane. Necessary for passive transport.
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sort of passive transport
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What are cell membranes permeable to?
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Hydrophobic molecules (steroid hormones, O2, CO2) & Small polar molecules (EtOH >> H2O)
Because membranes contain protein channels for ions |
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What are cell membranes impermeable to?
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Large polar molecules (glucose),
Ions/charged molecules (H+, Na+, ATP, amino acids) |
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Describe the different types of proteins used to transport molecules across cell membranes.
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Specific, Saturable, Inhibitable.
Uniport, Symbiport, Antiport |
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