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| structural basis of all cell membranes; mainly phospholipids arranged tail-to-tail in two layers, with hydrophilic heads of one dissolved in cytoplasmic fluid and heads of the other in extracellular fluid |
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| a cell membrane has a mixed composition (mosaic) of lipids and proteins, the interactions and motions of which impart fluidity to it |
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| membrane protein that passively or actively assists specific ions or molecules into or out of a cell. The solutes move through the protein's interior |
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| binds extracellular substances, such as hormones that can trigger change in cell activities |
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| one of a class of glycoproteins or glycolipids that project above the plasma membrane and that identifies a cell as nonself (foreign) or self (belonging to one's own body tissue) |
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| of multi-celled species, a plasma membrane protein that helps cells stick together in tissues and to extracellular matrixes such as basement membrane |
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| a membrane protein that helps from an open channel between the cytoplasm of adjoining cells |
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| difference in the number of molecules or ions of any one substance between two adjoining regions |
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| net movement of like ions or molecules from a region where they are most concentrated to an adjoining region where they are less concentrated; they move down their concentration gradient |
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| a difference in electric charge between adjoining regions |
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| difference in pressure between two adjoining regions |
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| built-in capacity of a cell membrane to prevent or allow specific substances from crossing it at certain times, in certain amounts |
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| diffusion of a solute across a cell membrane, through the interior of a transport protein |
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| pumping of a specific solute across a cell membrane against its concentration gradient, through the interior of a transport protein. Requires energy input, as from ATP |
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| active transport protein; pumps calcium ions across a cell membrane against their concentration gradient |
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| cotransporter that when energized, actively transports sodium out of a cell and helps potassium passively diffuse into it at the same time |
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| the mass movement of one or more substances in the same direction, most often in response to pressure |
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| diffusion of water across a selectively permeable membrane from a region where the water concentration is higher to a region where it is lower |
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| of two liquids, the one with the lower solute concentration |
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| of two fluids, the one with the higher solute concentration |
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| any fluid having the same solute concentration as another fluid to which it is being compared |
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| pressure exerted by a volume of fluid against a cell wall, membrane, or some other structure that contains it; also called turgor pressure |
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| the amount of pressure which, applied to a hypertonic fluid, will stop osmosis from occurring across a semipermeable membrane |
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| cell uptake of substances by forming vesicles from patched of plasma membrane. Three modes are receptor-mediated endocytosis, phagocytosis, and the bulk transport of extracellular fluid |
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| fusion of a cytoplasmic vesicle with a plasma membrane as it becomes part of the membrane, its contents are released to extracellular fluid |
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