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Campbell Biology 9th Edition - Chapter 7 Flashcards

Membrane Structure and Function

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896088571amphipathicmolecule that has both a hydrophilic region and a hydrophobic region such as a phosopholipid
896088572fluid mosaic modelstructural model of the plasma membrane where molecules are free to move sideways within a lipid bilayer
896088573selective permeabilityA property of biological membranes that allows them to regulate the passage of substances.
896088574integral proteinTypically transmembrane proteins with hydrophobic regions that completely span the hydrophobic interior of the membrane.
896088575peripheral proteinsprotein appendages loosely bound to the surface of the membrane and not embedded in the lipid bilayer.
896088576glycolipidmembrane carbohydrates that are covalently bonded to lipids
896088577glycoproteina protein with one or more carbohydrates covalently attached to it.
896088578transport proteinA transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane.
896088579aquaporina transport protein in the plasma membrane of a plant or animal cell that specifically facilitates the diffusion of water across the membrane
896088580diffusionprocess by which molecules tend to move from an area where they are more concentrated to an area where they are less concentrated
896088581concentration gradienta difference in the concentration of a substance across a distance
896088582passive transportThe movement of materials through a cell membrane without using energy
896088583osmosisdiffusion of water through a selectively permeable membrane
896088584tonicityThe ability of a solution to cause a cell within it to gain or lose water
896088585isotonicwhen the concentration of two solutions is the same
896088586hypotonichaving a lower concentration of solute than another solution
896088587hypertonicsolution that has a higher concentration of dissolved particles compared with another solution
896088588osmoregulationThe control of water balance in organisms living in hypertonic, hypotonic, or terrestrial environments.
896088589plasmolysiscollapse of a walled cell's cytoplasm due to a lack of water
896088590facilitated diffusionmovement of specific molecules across cell membranes through protein channels
896088591ion channela transmembrane protein channel that allows a specific ion to flow across the membrane down its concentration gradient
896088592gated channela transmembrane protein channel that opens or closes in response to a particular stimulus
896088593phagocytosisthe process by which a cell engulfs foreign substances or other cells
896088594pinocytosisprocess by which a cell takes in liquid from the surrounding environment
896088595Receptor mediated endocytosisallows the cell to acquire bulk quantities of specific substrates by receptors to which substrates attach which are then engulfed by the cell
896088596endocytosisprocess by which a cell takes material into the cell by infolding of the cell membrane
896088597exocytosisprocess by which a cell releases large amounts of material
896088598ligandA molecule that binds specifically to a receptor site of another molecule.
896088599electrogenic pumpAn ion transport protein that generates voltage across a membrane
896088600proton pumpAn active transport mechanism in cell membranes that uses ATP to force hydrogen ions out of a cell, generating a membrane potential in the process
896088601electrochemical gradientThe 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.
896088602cotransporta single ATP powered pump that transports one solute can indirectly drive the active transport of several other solutes in this mechanism as the solute that has been actively transported diffuses back passively through a transport protein its movement can be coupled with the active transport of another substance against its concentration gradient
896088603membrane potentialThe charge difference between a cell's 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.
896088604Na K PumpActive transporter that moves three Na+ out of a cell and two K+ into the cell against their respective concentration gradients.
896088605active transportenergy-requiring process that moves material across a cell membrane against a concentration difference

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