Term
| decribe the three lipid componants of an animal cell membrane (including leaflet) |
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Definition
1. phospholipids
2. glycolipids (outer leaflet)
3. cholesterol (both leaflets) |
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Term
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Definition
| the basic unit of a protein's tertiary structure |
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Term
| in a membrane, individual phospholipids are able to ______ and _________ but not to _________ |
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Definition
| phospholipids are able to rotate and move laterally; but NOT to flip |
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Term
| how does cholesterol affect the fluidity of the phospholipid bilayer at different temperatures? |
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Definition
hot: fatty acid chain tail of cholesterol interferes with phospholipid movement and makes it more solid than it might be otherwise
cold: interferes with phospholipid interaction and keeps the membrane from freezing |
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Term
| what functions do glycolipids serve in the outer leaflet of the cell membrane? |
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Definition
- interact with extracellular material/other cells
- protect the cell exterior |
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Term
| what is the difference between integral and peripheral membrane proteins? |
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Definition
integral: embedded in the membrane, usually by regions of hydrophobic amino acids, sometimes by being covalently attached to anchored lipids.
peripheral: attached by interactions (often ionic) with integral proteins |
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Term
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Definition
| a kind of integral protein that spans the phospholipid bilayer to emerge on either side. |
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Term
| what conditions lead to the formation of domains in membrane systems? |
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Definition
| where there are several possible interactions, some more or less favorable than others |
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Term
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Definition
| membrane lipids with long, mostly saturated hydrocarbon chains that like to interact with themselves and with cholesterol - these form fat (because of FA chain length) lipid raft microdomains |
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Term
describe how each molecule would get across the phospholipid bilayer and why:
O2
H2O
glucose
H+ |
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Definition
O2 and H2O would both be able to diffuse freely (small uncharged molecules, even though water is hydrophilic, obviously)
glucose is too big, and H+ is a charged ion - need transport proteins to get across |
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Term
| what kind of transport depends on concentration gradient? |
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Definition
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Term
| facilitated diffusion is supported by ________ channels and _________ carriers |
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Definition
| ALL channels and SOME carriers |
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Term
| what is a transporter? what are the three types? |
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Definition
a transporter is a passive diffusion protein that binds ions or molecules, changes shape, and then deposits them on the other side of the membrane
- uniporter: one molecule to the other side
- symporter: two molecules to the other side, same direction
- antiporter: two molecules to the other side, opposite directions |
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Term
| what is the difference between voltage-gated and ligand-gated ion channels? |
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Definition
voltage gated: open/close in response to electric potential across the membrane
ligand gated: open/close is response to binding of signal molecules |
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Term
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Definition
ATP-powered pump with two transmembrane domains and two ATP-binding domains
- transport a variety of molecules |
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Term
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Definition
ATPase pump that ONLY transports ions, phosphorylating itself in the process
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Term
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Definition
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Term
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Definition
ABC-class transmembrane protein pump
- 4 transmembrane domains packed in a bundle (passageway?)
- pumps out amphipathic drug molecules from the cell (ATP-coupled) |
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Term
| how would one develop resistance to hydrophilic drugs? hydrophobic? |
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Definition
hydrophilic drugs: would travel by transporters or channels; mutate these to keepthem out
hydrophobic drugs: diffuse across the membrane; use ATP-coupled pumps to get them out again |
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Term
| what are the two possible models for how MDR1 works? |
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Definition
1. substrate associates LATERALLY with MDR1, which flips it outside of the cell
2. substrate associates internally with MDR1, which pumps it through the cell wall |
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Term
| by what mechanism does the sodium-potassium pump work? |
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Definition
| it's an ATP driven (class P) transmembrane pump that is an antiporter and works by conformational change; for every 1ATP, 3sodium goes out and 2potassium comes in |
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