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AP Biology: Chapter 7 Flashcards

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7987176738Active TransportThe movement of a substance across a biological membrane against its concentration or electrochemical gradient0
7987176739Amphipathic MoleculeA molecule that has both a hydrophilic region and a hydrophobic region1
7987176740AquaporinsA transport protein in the plasma membrane of a plant or animal cell that specifically facilitates the diffusion of water across a membrane2
7987176741Concentration GradientAn increase or decrease in the number of particles per volume of a chemical substance in an area3
7987176742CotransportThe coupling of the "downhill" diffusion of one substance with the "uphill" transport against its own concentration gradient4
7987176743Diffusionthe process by which molecules move from an area of higher concentration to an area of lower concentration5
7987176744Electrochemical GradientThe diffusion gradient of an ion, which is affected by both the concentration difference of the ion across a membrane (a chemical force) and the ion's tendency to move relative to the membrane potential (an electrical force).6
7987176745Electrogenic PumpAn active transport protein that generates voltage across a membrane while pumping ions.7
7987176746Endocytosisthe process by which a cell membrane surrounds a particle and encloses the particle in a vesicle to bring the particle into the cell8
7987176747Exocytosisthe process by which a substance is released from the cell through a vesicle that transports the substance to the cell surface and then fuses with the membrane to let the substance out9
7987176748Facilitated Diffusionthe transport of substances through a cell membrane along a concentration gradient with the aid of carrier proteins10
7987176749FlaccidLimp. Lacking in stiffness or firmness, as in a plant cell in surroundings where there is no tendency for water to enter the cell.11
7987176750Fluid Mosaic ModelThe currently accepted model of cell membrane structure, which envisions the membrane as a mosaic of individually inserted protein molecules drifting laterally in a fluid bilayer of phospholipids.12
7987176751Gated ChannelsA protein channel in a cell membrane that opens or closes in response to a particular stimulus.13
7987176752HypertonicWhen comparing two solutions, the solution with the greater concentration of solutes14
7987176753HypotonicWhen comparing two solutions, the solution with the lesser concentration of solutes15
7987176754Ion ChannelsA transmembrane protein channel that allows a specific ion to flow across the membrane down its concentration gradient16
7987176755IsotonicWhen comparing two solutions, both have a solute concentration equal to that of the other solution17
7987176757Membrane PotentialThe charge difference between a cell's cytoplasm and the extracellular fluid, due to the differential distribution of ions.18
7987176758OsmoregulationThe control of water balance in organisms living in hypertonic, hypotonic, or terrestrial environments.19
7987176759Osmosisdiffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equal20
7987176760Passive TransportThe movement of substances across a cell membrane without the use of energy by the cell.21
7987176761PlasmolysisWhen a cell is in a hypertonic environment, the cell will lose water to its surroundings, shrink, and its plasma membrane will pull away from the wall22
7987176762Proton PumpAn active transport mechanism in cell membranes that consumes ATP to force hydrogen ions (H+) out of a cell and, in the process, generates a membrane potential23
7987176763Selective PermeabilityA property of biological membranes that allows some substances to cross more easily than others.24
7987176764Sodium-potassium pumpA special transport protein in the plasma membrane of animal cells that transports sodium out of the cell and potassium into the cell against their concentration gradients.25
7987176765TonicityThe ability of a solution to cause a cell within it to gain or lose water.26
7987176766Transport ProteinsProtein molecules that help to transport substances throughout the body and across cell membranes27
7987176767TurgidFirm. Walled cells become turgid as a result of the entry of water from a hypotonic environment.28
7987176768Extracellular MatrixA collection of extracellular molecules secreted by cells that provides structural and biochemical support to the surrounding cells.29
7987176769Carbohydrate chainMade up of sugar molecules and can be joined to protein for cell communication and identification.30
7987176770GlycoproteinProteins that have carbohydrates covalently bonded to them.31
7987176771CholesterolSteroid present in the plasma membranes of animal cells. A large amount of this in a phospholipid bilayer at High Temperatures reduces membrane fluidity, but at Lower Temperatures prevents the membrane from solidifying.32
7987176772Microfilaments of cytoskeletonProvide structure and support to the cell, allow for movement and stabilization of organelles.33
7987176773Peripheral proteinBound to the surface of the membrane and integral proteins, but not embedded in the lipid bilayer.34
7987176774GlycolipidFatty acids with linked sugar groups that are key structural elements in cell membranes and precursors of other biologically active molecules important in cell signaling35
7987176775Integral proteinExtend entirely through the membrane with both hydrophobic and hydrophilic ends (imbedded)36

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