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17 Cards in this Set
- Front
- Back
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what are the molecular components of the cell membrane? |
head: glycogen + phospholipid
tails: fatty acid tails |
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how do the molecular components respond to water? |
- heads are sumbmerged in water - tails remain exposed & out of the water |
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what are the proteins in the membrane? |
- glycoprotein: polysacccharide + protein - glycolipid: polysaccharide + lipid - peripheral proteins: attached to surface of lipid bilayer - integral proteins: pores, on the side of bilayer - cholesterol |
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what is the fluid mosaic model? |
fluid: components move about in their layer
mosaic: sccattered pattern of proteins |
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what are the 4 mechanisms of transport? |
1) diffusion - simple & facilitated 2) osmosis 3) active transport 4) bulk transport |
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what is osmosis? |
net movement of water molecules from a region of higher water potential to a region of lower water potential through a selectively permeable membrane |
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what is water potential? |
- tendency of water molecules to move about - random movements of water molecules until equilibrium is reached |
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what is diffusion? |
net movement of particles from region of higher concentration to a region of lower concentration (membrane not required) |
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what is simple diffusion? |
- through pores - small molecules - lipid-soluble solutes |
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what is facilitated diffusion? |
through channel & carrier proteins carrier protein - lipid insoluble solutes - binding of substrates cause proteins to change shape channel protein - smaller lipid-insoluble solutes - mostly ions selected based on size and charge |
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what are the key features of active transport? |
- works against a concentration gradient - requires ATP energy - highly selective - involves proteins pumps |
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what is bulk transport? |
- movement of vesicles of matter across the cell membrane - requires ATP |
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what is exocytosis? |
export of substances (eg. enzymes) via vesicles |
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what is endocytosis? |
import of substances into the cell |
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what is pinocytosis? |
import of liquid matter |
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what is phagocytosis? |
import of solid matter |
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water in cell wall |
flaccid : normal water concentration turgid : too much water plasmolysed : lack of water |
