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| a property of biological membranes that allows some substances to cross more easily than others |
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| a mol-ecule that has both a hydrophilic region and a hydrophobic region |
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| the currently accepted model of cell membrane structure, which envisions the membrane as a mosaic of individual protein molecules drifting laterally in a fluid bilayer of phospholipids |
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| typically a transmembrane protein with hydrophobic regions that completely spans the hydrophobic interior of the membrane |
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| a protein appendage loosely bound to the surface of a membrane and not embedded in the lipid bilayer |
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| a lipid covalently bonded to a carb |
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| a protein covalently bonded to a carb |
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| a transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane |
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| a transport protein in the plasma membrane of a plant or animal cell that specifically facilitates the diffusion of water across the membrane |
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| the spontaneous tendency of a substance to move down its concentration gradient from a more concentrated to a less concentrated area |
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| an increase or decrease in the density of a chemical substance in an area |
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| the diffusion of a substance across a biological membrane |
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| the diffusion of water across a selectively permeable membrane |
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| the ability of a solution to cause a cell within it to gain or lose water |
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| having the same solute concentration as another solution |
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| in comparing two solutions, refering to the one with a greater solute concentration |
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| in comparing two solutions, referring to the one with the lower solute concentration |
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| how organisms regulate solute concentrations and balance the gain and loss of water |
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| a phenomenon in walled cells in which the cytoplasm shriveles and the plasma membrane pulls away from the cell wall when the cell loses water to a hypertonic enviroment |
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| the spontaneous passage of molecules and ions, bound to specific carrier proteins, across a bilogical membrane down their concentration gradient |
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| protein channel in a cell membrane that allows passage of a specific ion down its concentration gradient |
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| a protein channel in a cell membrane that opens or closes in response to a particular stimulus |
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| the movement of a substance across a biological membrane against its concentration or electrochemical gradient with the help of energy input and specific transport proteins |
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| a component of water potential that is propertional to the number of dissolved solute molecules in a solution and measures the effect of solutes on the direction of water movement |
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| the charge difference between a cell's cytoplasm and the extracellular fluid, due to the differential distribution by exposure of ions |
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| the diffusion gradient of an ion, representing a type of potential energy that accounts for both the concentration difference of the ion across a membrane and its tendency to move relaive to the membrane potential |
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| an ion transport protein that generates voltage across the membrane |
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| an active transport mechanism in cell membranes that uses ATP to force hydrogen ions out of cell, generating a membrane potential in the process |
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| the coupling of the downhill diffusion of one substance to the uphill transport of another against its own concentration gradient |
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| the cellular secretion of macromolecules by the fusion of vesicles with the plasma membrane |
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| the cellular uptake of macromolecules and particulate substances by localized regions of the plasma membrane that surround the substance and pinch off to form an intracellular vesicle |
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| a molecule that binds specifically to a receptor site of another molecule |
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