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37 Cards in this Set
- Front
- Back
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Selective Permeability
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The plasma membrane allows some substances to cross it more easily than others.
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Amphipathic
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A molecule that has both a hydrophilic region and hydrophobic region.
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Fluid Mosaic Model
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The membrane is a fluid structure with a a mosaic of various proteins embedded in or attached to a double layer of phospholipids.
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Integral Proteins
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These are proteins that penetrate the hydrophobic interior of the lipid bilayer.
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How does cholesterol affect the plasma membrane?
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It keeps it fluid, preventing the phospholipids from becoming too rigid at low temperatures.
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Peripheral Proteins
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They are appendages loosely bound to the surface of the plasma membrane.
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Glycolipids
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Lipids in the presence of carbohydrate
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Transport Proteins
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Proteins that span the membrane allowing hydrophilic substances to pass through the membrane.
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Aquaporins
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Transport proteins that allow water to pass through.
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Diffusion
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Passive transport of material down a gradient.
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Concentration Gradient
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The region along which the density of a chemical substance increases or decreases. No work must be done to make this happen.
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Passive Transport
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Diffusion of a substance across a biological membrane using NO ENERGY.
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Osmosis
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Diffusion of water
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Tonicity
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The ability of a surrounding solution to cause a cell to gain or lose water.
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Isotonic
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The concentration is the same within the cell and outside the cell
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Hypertonic
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If the solution is hypertonic, it has a higher concentration relative to the cell in it. This will cause the cell to shrivel as water leaves it.
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Hypotonic
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The solution has a lower concentration than the cell in it. This will cause the cell to swell or burst as water enters it.
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Osmoregulation
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The control of solute concentrations and water balance.
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Turgid
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Very firm. Used when referring to plants.
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Flaccid
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Limp. Used when referring to plants.
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Facilitated Diffusion
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This is diffusion but it is assisted by transport proteins which only allow some substances to pass through but not others.
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Plasmolysis
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A plant cell undergoes this when it is placed in a hypertonic solution, forcing its plasma membrane to pull away from the wall.
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Ion Channels
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Channel proteins that transport ions.
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Gated Channels
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Ion channels that open or close in response to a stimulus.
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Active Transport
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The solute is pumped across the membrane against its gradient, forcing the cell to use energy and do work. This is done by carrier proteins.
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Sodium-Potassium Pump
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Active transport of sodium and potassium across the membrane, exchanging Na for K.
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Membrane Potential
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Voltage across a membrane
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Electrochemical Gradient
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The combination of the chemical force(concentration gradient) and the electrical force(the effect the membrane potential has on the ion's movement).
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Electrogenic Pump
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A transport protein that generates voltage across a membrane. e.g. sodium-potassium pump
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Proton Pump
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Actively transports protons out of the cell in fungi, plants, and bacteria.
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Cotransport
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An ATP-powered pump that transports a specific solute that indirectly drives the active transport of another solute.
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Exocytosis
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The cell secretes certain molecules by the fusion of vesicles with the plasma membrane
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Endocytosis
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The cell takes in molecules by forming new vesicles from the plasma membrane .
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Ligands
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Any molecule that binds specifically to a receptor site on another molecule.
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Phagocytosis
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The cell engulfs a large particle.
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Pinocytosis
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The cell engulfs droplets of extracellular fluid that has dissolved molecules
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Receptor-Mediated Endocytosis
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Allows the cell to acquire bulk quantities of specific substances.
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