BIO 122 Lecture Notes - Lecture 4: Osmoregulation, Lysis, Phagocytosis
24 Apr 2016
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Document Summary
Allows some substances to cross it more easily than others. Amphipathic (both a hydrophilic and hydrophobic region) Model of cell membrane which envisions the membrane as a mosaic of protein molecules drifting laterally in a fluid bilayer of phospholipids. Proteins are not randomly distributed but in specialized patches. Membranes are held together by hydrophobic interactions (weaker than covalent bonds) Protein and lipids shift laterally and sometimes lipids flip flop rapidly. Proteins move by motor proteins in the cell along cytoskeletal fibers; other proteins are immobile, attached to the cytoskeleton or extra cellular matrix. Fluidity affects permeability and ability of membrane proteins to move to where their function is needed. If solidified, enzymatic proteins in membrane in the membrane may become inactive if they need to move to do their function. Membranes do not support protein function if too fluid too. Membrane remains fluid as temp decreases until the phospholipids pack and solidified.
