BIO 122 Chapter Notes - Chapter 7: Electrochemical Gradient, Biological Membrane, Facilitated Diffusion
20 Oct 2016
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Document Summary
Held together by hydrophobic interactions - weaker than covalent bonds. Phospholipid bilayer exist as stable boundary btw 2 aqueous compartments. Amphipathic - (molecule) both hydrophilic region and a hydrophobic regions. Plasma membrane - boundary living cells from surroundings. Fluid mosaic model - a membrane is a fluid structure with a mosaic of various proteins embedded in it. Selective permeability - allows certain substances to pass and others not. Temperature of membrane solidifies depending on types of lipids. Membrane made of phospholipids w/ unsaturated hydrocarbon tails fluid if lower temperatures. Temp different effects on membrane fluidity. Fluidity affects permeability and ability of membrane proteins to move -- affects function. Membrane solidifies: permeability changes and enzymatic proteins in membrane become inactive. Membrane too fluid: cannot support protein function. Evolution of membrane lipid composition: cell membranes respond to temp change allow organisms to live in varying temp conditions. Proteins exist in phospholipid bilayer with hydrophilic regions protruding.
