Chapter 7 SG - Chapter 7 Selective Permeability- plasma...

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Chapter 7 Selective Permeability- plasma membrane allows some substances through membrane Amphipathic Molecule- phospholipid has both hydrophilic/phobic regions that allows a shield (skin, for example) for inner membrane Fluid Mosaic Model- the currently accepted model for arrangement of molecules in a cell attached to bilayer Davson-Danielli Sandwich Model- 1960s model was a phospholipid bilayer between two layers of protein Singer and Nicholson- proposed mosaic model that stated membrane proteins are individually placed on bilayer with H-philic exposed Membrane Fluidity- held by h-phobic interactions, adjacent lipid movement (10 7 times/sec) and flip flop (once/month) a. Solidified- when temp. decreases; unsaturated fats have “tails and kinks” that prevent solidification\ b. Cholesterol- decreases membrane fluidity @ room temp (temp buffer) that prevents solidification at room temp Integral Proteins- penetrate membrane, thus transmembrane protein Peripheral Proteins- not embedded into membrane but bound loosely (in cytoplasm); often bound to Integrals Transport (1 st )- protein function that works as selective channel that can passively and actively transport substances to other side Enzymatic Activity (2 nd )- protein function that has active site ready for metabolic processes Signal Transduction- (3 rd )- has binding site specific with messenger; signal at other side of membrane while receptor inside changes Cell-cell Recognition- glycoproteins w/ tags specifically recognized by other cells; crucial to organism function
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This note was uploaded on 08/27/2010 for the course BIO 8432 taught by Professor Lang during the Spring '10 term at Northwestern IA.

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