Lecture 2 - Fluid Compartments, Diffusion, And Membrane Permeability Flashcards
What is diffusion?
Diffusion is the spontaneous movement of individual molecules from areas of high concentration to low concentration. This movement of solutes is completely independent of other solutes and solvent molecules.
What is flux?
Flux is the direction and magnitude of a solute’s movement
What does unidirectional movements refer to?
Unidirectional movements refers to the direction of a solute in one direction.
What does net movements refer to?
Net movement (net flux) is the difference between two (or more) unidirectional movements (multiple fluxes)
What is the difference between bulk flow and diffusion?
Diffusion refers to the spontaneous movement of individual molecules. Whereas bulk flow refers to the movement/flow of an entire body due to pressure.
What is diffusion driven by?
Concentration gradient
What is bulk flow driven by?
Pressure gradient
What does Fick’s law describe?
Fick’s law describes the net diffusional flux
What does Fick’s law describe?
Fick’s law describes the net diffusional flux
What is net flux proportional to?
= the number of molecules over a difference in time
= diffusion coefficient x the surface area x the concentration difference over the diffusion distance
What does P define?
P can be used to define the selectivity of a membrane for solutes that are permeable to it
What is solubility diffusion?
Solubility diffusion explains the movement of most non-electrolytes (uncharged solutes)
