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AP Biology Unit 2 - Chapter 7 Membranes Flashcards

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8185159733plasma membraneseperates the living cell from its surroundings. Contros traffic in and out of the cell. Is selectively permeable.0
8185159734selectively permeableallows some substances to cross more easily than others.1
8185159735phospholipidsmost abundant lipids2
8185159736lipids and proteinsmain macromolecules in membranes3
8185159737amphipatic moleculeshave hydrophobic and hydrophilic regions4
8185159738fluid mosaic modelThe arrangement of phospholipids and proteins in biological membranes is described by the...5
8185159740transmembrane proteinsthe integral protein completely spans the membrane as...6
8185159741integral proteinsproteins that penetrate the hydrophobic interior of the lipid bilayer7
8185159742peripheral proteinsproteins that are not embedded in the lipid bilayer8
8185159743cell-cell recognitionthe ability of a cell to disitnguish one type of neighboring cell from another.9
8185159745transport proteinsproteins that span the membrane.10
8185159746channel proteinstransport proteins that have a hydrophilic channel that certain molecules or ions use as a tunnel though the membrane.11
8185159747aquaporinschannel proteins that facilitate the passage of water12
8185159748carrier proteinstransport proteins that bind to molecules and change shape to shuttle them across the membrane.13
8185159749diffusionmovement of molecules of any substance to spread out in available space14
8185159750concentration gradientthe region along which the density of a chemical substance increases or decreases.15
8185159751passive transporttransport that requires no energy from the cell to make it happen16
8185159752osmosisthe diffusion of water across a selectively permeable membrane17
8185159753tonicitythe ability of a surrounding solution to cause a cell to gain or lose water.18
8185159754isotonic (animal cell)if a cell with no cell wall is immersed in an enviroment where there is no net movement of water across the plasma membrane. Stays the same.19
8185159755hypertonic (animal cell)when the cell is immersed in a solution where it loses water to its environment, shrivels and probably dies.20
8185159756hypotonic (animal cell)when a cell is immersed in a solution, water enters the cell faster than it leaves, it swells and lyses (explodes) like an overfilled water balloon.21
8185159759turgidwhen the plant cell is very firm, which is a healthy state for most plant cells.22
8185159760hypotonic (plant cell)when a plant cell is immersed in a __________ solution the cell contents swell due to osmosis until the elastic cell wall exerts turgor pressure on the cell that opposes further water outake.23
8185159761isotonic (plant cell)when a plant cell is immersed in a _______ solution; there is no net movement. The cell becomes flaccid and the plant may wilt.24
8185159762flaccidlimp, not firm or strong (If a plant is not watered enough, its leaves become droopy and flaccid.)25
8185159763hypertonic (plant cells)the plant cell loses water, its volume shrinks. The plasma membrane pulls away from the wall, this is plasmolysis. It is lethal to the cell.26
8185159764plasmolysisThis happens when a cell shrinks inside its cell wall while the cell wall remains intact. The plasma membrane pulls away from the wall.27
8185159765facilitated diffusionthe passive movement of molecules down their concentration gradient with the help of transport proteins.28
8185159766ion channels (gated channels)Channels that open or close depending on the presence or abscence of an electrical, chemical, or physical stimulus.29
8185159768active transporttransport that requires the cell to expend metabolic energy and enables a cell to maintain internal concentrations of small molecules. Requires energy.30
8185159769ATPsupplies energy for most active transport31
8185159770sodium-potassium pumptransport protein that, translocating the bound solute across the membrane. Exchanges sodium ions (Na) for potassium ions (K) across the plasma membrane of animal cells.32
8185159774sodium-potassium pumpmajor electrogenic pump in animals. Restores the electrochemical gradient by setting up a concentration gradient. It pumps 2 K ions for every 3 Na ions that it moves out, it generates a voltage.33
8185159777exocytosistransport vesicle budded from the Golgi apparatus is moved by the cytoskeleton to the plasma membrane. When the 2 membranes come in contact, the bilayers fuse spill the contents.34
8185159778endocytosisa cell brings in biological molecules and particulate matter by forming new vesicles from the plasma membrane. 3 types: phagocytosis, pinocytosis and receptor-mediated endocytosis.35
8185159779phagocytosisa cell engulfs a particle in a vacuole. The vacuole fuses with a lysosome to digest the particle.36
8185159780pinocytosismolecules are taken up when extracellular fluid is "gulped" into tiny vesicles.37
8185159781receptor-mediated endocytosisendocytosis that enables a cell to acquire bulk quantities of specific materials that may be in low concentrations in the environment.38
8185159782lipoproteinscomplexes of proteins and lipids. Cholesterol travels in low density _______39
8185159783ligandsA molecule that binds specifically to a receptor site of another molecule.40

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