PHGY 214 Lecture 2: PHYG214 W1L2 notes
14 Feb 2017
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Document Summary
Membrane is a key component in excitable membranes, by separating components responsible for the creation of gradients. Cholesterol has an important function of maintaining fluidity of the membrane (it"s embedded in the lipid bilayer) If it can move, this will be determined by: 1) concentration gradient or 2) electrical gradient. Ions are charged, so we can have an excess or deficiency of charge. Lipids and gas pass freely (lipid soluble chemicals, as they have the same chemical composition as the membrane), gases pass through diffusion. Water soluble molecules - the basic fundamental components of life, they can only get in if there is a permeability pathway: either 1) carriers, 2) pumps, or 3) channels. Water molecules themselves can squeeze past the membrane. Aquaporins found in most cells, only job is to let water through. If there is a buildup on either sides of a barrier (that allows passage through it), the net movement is towards the side with lower concentration.
