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18 Cards in this Set
- Front
- Back
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Nernst Equation |
(RT)/(ZF)* ln([xout])/([xin]) |
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Random Walk |
principle of stochastic behavior: - gas molecules with freedom = random movement - random movement = predictable collectively - as temporal resolution increases, stochastic movement becomes more similar |
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how is velocity proportional to temperature? |
as temp increases, velocity of particles increase |
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friction |
- a form of dissipation that decreases order - friction erases order in the directed motion of a particle |
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what mechanism accounts for aqueous diffusion? |
thermal agitation |
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diffusion coefficient |
D=(jump distance)^2/(2*time scale) - everything depends on the time scale - diffusion time and distance are linearly correlated |
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Nernst Planck Equation |
- describes how a particle moves in a particular environment - movement is proportional to electrical gradient Current=Is=zFMs, where z=valence, Ms=flux, F=faraday's constant |
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What is the relationship between resistance and conduction? |
inverse relationship |
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how are diffusion and mobility related? |
diffusion = thermal agitation thermal agitation is opposed by friction so, friction opposes diffusion |
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electrodiffusion: what is the relationship b/w diffusion and electric field? what equation is used to describe this? |
1. diffusion and electric field are additive 2. Nernst-Planck equation |
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Where does electrical neutrality exist? |
everywhere except near the membranes |
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What does the GHK equation do for us? |
- gives the resting membrane potential (Vm) - must know the concentrations and relative permeability (potassium permeability = 1) - |
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What is the resting membrane potential (Vm)? |
- Vm= potential at which most cells operate within the resting state - each cell has a resting potential - calculated with the GHK equation |
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what is Brownian dynamics? |
- if there is sufficient thermal energy, ions can move to the next minimum (over the energy barrier) - hopping over barriers (jumping from minimum of one sine wave to the next) |
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What is the energy barrier model? |
I=zF (Jinward-Joutward) - current is related to the electrical gradient |
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current-voltage relationship |
- current = y-axis - x-axis intersection = point of change in direction of ion flow (reversal potential) |
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outward rectification |
-current can only go out - acts as a diode - current flows from inward to outward - out = delta=1=rate-limiting barrier; located on the outside margin of the membrane |
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inward rectification |
- flows from out to in - plays a profound role in action potentials - out=delta=0=rate-limiting barrier; located on the inside margin of the membrane |
