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15 Cards in this Set
- Front
- Back
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define diffusion
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the process whereby particles in a gas or liquid tend to intermingle due to their spontaneous motion caused by thermal agitation
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Diffusion is the result of....
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the random thermal motions of molecules
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Describe the underlying molecular movement in diffusion?
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it is random and is related to the heat in the solution
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does the process of diffusion require the cell to use energy?
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No
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what is an electrolyte?
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a substance that dissolves into charged particles in solution
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how is Net Flux related to the concentration difference?
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it is equal to concentration difference
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Formula for flux
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J=(diffusion coefficient X concentration difference) /membrane thickness
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what are the two things that affect the diffusion coefficient?
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1) Molecular size and shape
2) The hydrated radius of ions |
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what does the term partitioning refer to with respect to membrane solubility ?
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The phenomenon of different solubility of a solute in oil and water
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what is the partition coefficient?
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(Kp) of a substance is the ratio of its concentration in oil relative to its concentration in water.
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how do we modify the Flux equation to deal with a Kp that is >1
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J=( Kp x diffusion coefficient x concentration difference) /membrane thickness
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how to hydrophobic solutes diffuse in comparison to hydrophilic solutes?
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hydrophobic (lipophilic) solutes cross the membrane by diffusion easily.
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what are the two main determinants of PERMEABILITY
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a) solute size
b) its oil-water partition coefficient |
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why do multi cellular animals require a circulatory system?
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diffusion only works well over short distances
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what determines capillary thickness
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capillary thickness has DIRECT relationship to tissue metabolic rate
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