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Related Flashcards
Cards In This Set
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Diffusion
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Movement of molecules across cell membrane from area of higher concentration to area of lower concentration
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Flux
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Amount of material crossing a surface per unit of time
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Net Flux
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Equal diffusion between 2 compartments (diffusion equilibrium) leading to no net movement
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Diffusion Equilibrium
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Equal diffusion between 2 compartments
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3 Factors the magnitude of net flux is dependent on.
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Concentration difference across the membrane
Surface area of the membrane
Membrane permeability constant
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Kp
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Permeability for a particular molecule at a particular temperature.
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Diffusion through Bi-lipid layer
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Non-polar molecules dissolve in the lipids in the membrane. Therefore they diffuse more rapidly.
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Diffusion of Ions through protein channels
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Protein channels formed by integral proteins allow ions to diffuse across the membrane,
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Electrochemical Gradient
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Seperation of electrical charges across the membrane called the membrane potential -provides force that drives + ions in and - ions out.
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Channel gating
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Opening/closing of ion channels which changes permeability of membrane.
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Modulators of channel gating-(3)
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Ligand gated, voltage gated, mechanosensitive
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Ligand Gated channels
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Control by allosteric or covalent modulation
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Voltage gated
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Changes in membrane potential
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Mechanosenstitive
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Stretching
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Transporters/carriers
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Integral membrane proteins mediate movement of molecules that are too polar or too large to move by diffusion
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