AP Biology, Ch. 7-Membrane Structure & Function Flashcards

Campbell 7e Ch7

580504583	active transport	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.	0
580504584	amphipathic molecule	A molecule that has both a hydrophilic region and a hydrophobic region.	1
580504585	aquaporin	A transport protein in the plasma membrane of a plant or animal cell that specifically facilitates the diffusion of water across the membrane (osmosis).	2
580504586	bulk transport	Mechanism of large molecule (proteins, polysaccharides, particles) crossing membrane involving vesicles (exocytosis, endocytosis) bk	3
580504587	concentration gradient	An increase or decrease in the density of a chemical substance in an area. Cells often maintain ___ of ions across their membranes. When a ___exists, the ions or other chemical substances involved tend to move from where they are more ___to where they are less ___.	4
580504588	contractile vacuole	A membranous sac that helps move excess water out of the cell.	5
580504589	cotransport	The coupling of the "downhill" diffusion of one substance to the "uphill" transport of another against its own concentration gradient.	6
580504590	diffusion	The spontaneous tendency of a substance to move down its concentration gradient from a more concentrated to a less concentrated area.	7
580504591	electrochemical gradient	The diffusion gradient of an ion; a type of potential energy that accounts for the concentration difference of the ion across a membrane and its tendency to move relative to the membrane potential.	8
580504592	electrogenic pump	An ion transport protein generating voltage across the membrane.	9
580504593	endocytosis	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.	10
580504594	exocytosis	The cellular secretion of macromolecules by the fusion of vesicles with the plasma membrane.	11
580504595	facilitated diffusion	The spontaneous passage of molecules and ions, bound to specific carrier proteins, across a biological membrane down their concentration gradients.	12
580504596	flaccid	Limp. Walled cells are ___in isotonic surroundings, where there is no tendency for water to enter.	13
580504597	fluid mosaic model	The currently accepted model of cell membrane structure, which envisions the membrane as a ___ of individually inserted protein molecules drifting laterally in a __ bilayer of phospholipids.	14
580504598	gated channel	A protein channel in a cell membrane that opens or closes in response to a particular stimulus.	15
580504599	glycolipid	A lipid covalently attached to a carbohydrate.	16
580504600	glycoprotein	A protein covalently attached to a carbohydrate.	17
580504601	hypertonic	In comparing two solutions, referring to the one with a greater solute concentration.	18
580504602	hypotonic solution	In comparing two solutions, the one with a lower solute concentration.	19
580504603	integral protein	Typically transmembrane proteins with hydrophobic regions that completely span the hydrophobic interior of the membrane.	20
580504604	isotonic	Having the same solute concentration as another solution.	21
580504605	ligand	A molecule that binds specifically to a receptor site of another molecule.	22
580504606	membrane potential	The charge difference between the cytoplasm and extracellular fluid in all cells, due to the differential distribution of ions; affects the activity of excitable cells and the transmembrane movement of all charged substances.	23
580504607	osmoregulation	The control of water balance in organisms living in hypertonic, hypotonic, or terrestrial environments.	24
580504608	osmosis	The diffusion of water across a selectively permeable membrane.	25
580504609	passive transport	The diffusion of a substance across a biological membrane.	26
580504610	peripheral protein	Protein appendages loosely bound to the surface of the membrane and not embedded in the lipid bilayer.	27
580504611	phagocytosis	A type of endocytosis involving large, particulate substances.	28
580504612	pinocytosis	A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.	29
580504613	plasmolysis	A phenomenon in walled cells in which the cytoplasm shrivels and the plasma membrane pulls away from the cell wall when the cell loses water to a hypertonic environment.	30
580504614	proton pump	An active transport mechanism in cell membranes that consumes ATP to force hydrogen ions out of a cell and, in the process, generates a membrane potential.	31
580504615	receptor-mediated endocytosis	The movement of specific molecules into a cell by the inward budding of membranous vesicles containing proteins with receptor sites specific to the molecules being taken in; enables a cell to acquire bulk quantities of specific substances.	32
580504616	selective permeability	A property of biological membranes that allows some substances to cross more easily than others.	33
580504617	sodium-potassium pump	A 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.	34
580504618	tonicity	The ability of a solution to cause a cell to gain or lose water. Dependent upon solute concentration and membrane permeability. Bk	35
580504619	transport protein	A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane.	36
580504620	turgid	Firm. Walled cells become ____ as a result of the entry of water from a hypotonic environment.	37