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Unit 2 Chapter 7 (Summer test)

컨트롤 버튼이 '내비게이션' 모드로 변경되었습니다.
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  • Active transport

    Movement of a substance across a biological membrane against its concentration or electrochemical gradient with the help of energy input and specific transport proteins

  • Amphipathic molecule

    A molecule that has both a hydrophilic region and a hydrophobic region.

  • 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)

  • Concentration gradient

    An increase or decrease in the density of a chemical substance in an area. Cells often maintain concentration gradients of ions across their membranes. When a gradient exists, the ions or other chemical substances involved tend to move from where they are more concentrated to where they are less .

  • Cotransport

    The coupling of the down hill diffusion of one substance to the uphill transport of another against its own concentration gradient.

  • Diffusion

    The spontaneous tendency of a substance to move down its concentration gradient from a more concentrated to a less concentrated area.

  • Electrochemical gradient

    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 relative to the membrane potential.

  • 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.

  • Exocytosis

    The cellular secretion of macromolecules by the fusion of vesicles with the plasma membrane.

  • Facilitated diffusion

    The spontaneous passage of molecules and ions, bound to specific carrier proteins, across a biological membrane down their concentration gradients.

  • Flaccid

    Limp. A walled cell is flaccid in surroundings where there is no tendency for water to enter.

  • Fluid mosaic model

    The 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.

  • Gated channel

    A protein channel in a cell membrane that opens or closes in response to a particular stimulus.

  • Glycoprotein

    A protein covalently attached to a carbohydrate.

  • Hypertonic

    In comparing two solutions, referring to the one with a greater solute concentration.

  • Hypotonic

    In comparing two solutions, referring to the one with a lower solute concentration.

  • Integral protein

    Typically a transmembrane protein with hydrophobic regions that completely spans the hydrophobic interior of the membrane.

  • Ion channel

    Protein channel in a cell membrane that allows passage of a specific ion down its concentration gradient.

  • Isotonic

    Having the same solute concentration as another solution

  • Ligand

    A molecule that binds specifically to a receptor site of another molecule.

  • Membrane potential

    The charge difference between a cells cytoplasm and the extracellular fluid, due to the differential distribution of ions. Membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substances.

  • Osmoregulation

    The regulation of solute and water concentrations in body fluids by organisms living in hyperosmotic, hypoosmotic, and terrestrial environments.

  • Osmosis

    The diffusion of water across a selectively permeable membrane.

  • Passive transport

    The diffusion of a substance across a biological membrane.

  • Peripheral protein

    A protein appendage loosely bound to the surface of a membrane and not embedded in the lipid bilayer.

  • Phagocytosis

    A type of endocytosis involving large, particulate substances, accomplished mainly by macrophages, neutrophils, and dendritic cells.

  • Pinocytosis

    A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.

  • 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.

  • Proton pump

    An active transport mechanism in cell membranes that uses ATP to force hydrogen ions out of a cell, generating a membrane potential in the process.

  • 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.

  • Selective permeability

    A property of biological membranes that allows some substances to cross more easily than others

  • 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.

  • Tonicity

    The ability of a solution to cause a cell within it to gain or lose water

  • Transport protein

    A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane.

  • Turgid

    Very firm. A walled cell become turgid if it has a greater solute concentration than its surroundings, resulting in entry of water.