BIOLOGY 2A03 Lecture Notes - Lecture 3: Fick'S Laws Of Diffusion, Vacuum Permeability, Fick Principle
22 Feb 2018
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Document Summary
Cell membrane allow cells to isolate their contents from their environment. Cells use energy to control intracellular conditions via transportation of substances across membranes (highly demanding) Potential energy is stored in chemical (diffusion) and electrical (voltage) gradients between intracellular and extracellular environments which is used to power many biological processes. Fundamental properties of membranes are considered prior knowledge. Phospholipid bilayer forms a selective barrier, but its function (e. g. fluidity) can be affected by environmental conditions (e. g. temperature) Transportation of substances in and out of organelles. Active transport - require energy, move substance against gradients. Concentration gradient = chemical driving force for diffusion. Movement of solute from high to low conc. Net flux = flux 1 - flux 2, diffusion in direction of lower conc. Net diffusion flux rate (f) of uncharged solute is proportional to conc. Difference between 2 locations ("chemical driving force") and membrane "permeability"
