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23 Cards in this Set
- Front
- Back
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Entropy (2)
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-measure of disorder
- high entropy = spontaneous = high disorder |
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Brownian motion (2)
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-spontaneous movement of molec's in H20
-due to kinetic energy in H20 |
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What effects rate of diffusion/net flux (2)
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-greater diff in concentration
-shorter distance (less time to travel) (both increase rate) |
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Fick's Law
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0(net)= -D(deltaC/deltaX)
0(net) = flux across membrane deltaC = concentration difference btw compartments deltaX = distance i.e. - thickness of membrane (:. smaller distance = faster rate) "-" b/c moving from [higher] -> [lower] D = diffusion coefficient |
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D (diffusion coefficient)
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-determines speed of diffusion
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Stokes-Einstein Equ
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D = (K*Temp)/(6pi*radius*viscosity of solvent)
D is proportional to Temp/(radius*viscosity) Constant = K/6pi |
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Einstein's Equ
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t = (deltaX)^2/2D
t = time it takes for molec to travel distance X D is in denominator b/c higher D means less time |
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Einsteins equ tells us that a small increase in distance results in _______, therefore ______
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-a large increase in time
-:. diffusion only works for short distances |
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Membrane Flux Equation
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-measures # of molecs moving across membrane in given time
O(Net)=P(deltaC) =P(C1-C2) =P(Cin-Cout) P = permeability |
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What types of molecules are more permeable?
less? |
-lipid soluble
- neutral molec's smaller that 8A (b/c putative pores are 8A) -polar molecs. Even small ones. |
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permeability = 0 at ____
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-200Da
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hydrostatic pressure
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-factor in osmosis
-pressure on surface of liquid (from gravity, etc) |
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osmotic pressure (pi?)
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-pressure required to stop H20 flowing into a compartment
(pi?)= iCRT |
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water moves (toward/away)? compartment w/ higher osmolarity?
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-toward
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osmolarity of body
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-300mosM (0.3osM)
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transient osmotic pressure
what type of molecs contribute to osmotic pressure? |
-beginning. initial measurement. no solutes of any kind have diffused
-only impermeable solutes. Or else they will equalize |
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steady state osmotic pressure
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-end point. All permeable solutes have diffused
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osmolarity vs. molality
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=1 mole solute/1 mole solution
=1 mole solute/1 kg solvent |
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Carrier-mediated transport (vs diffusion) (5)
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- faster
- specificity (chemical binding) - can reach saturation - substrates compete - binding sites can be blocked/enhanced |
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passive transport
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-always goes down gradient
-can be gated, non-gated -> controlled by hormons/neurotransmitters |
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active transport (2)
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-pumps
-requires ATPase or secondary active transport ([gradient] built up by ATP) |
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Na+/K+ pumps (4)
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-most important transport
-3 Na+ out/2 K+ in -uses 1 ATP - 1/2 of ATP in body is used to maintain this pump |
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diameter of ave cell
ave distance from cell to nearest capillary |
-10um
-100um |
