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Unformatted text preview: Membrane Transport (Part I) Dr. Susan C. Frost BCH 6206 Reading: Chapter 20, pgs 728-738 and selected references copyright: Susan C. Frost Facilitated Transport Topics for Membrane Transport Part I Passive transport Electrochemical gradient Facilitated transport Glucose transport Transport Across a Lipid Bilayer Water 2 Gases 2 Small uncharged polar molecules Urea Ethanol Large uncharged polar molecules Glucose Ions K Mg Ca Cl HCO HPO 2+ 2+ +-- 2- 4 Charged polar molecules Amino acids Glucose-6-phosphate ATP H O O CO N NO 2 2 Figure 1 Membrane Permeability C aq 1 C m 1 C m 2 C aq 2 x K = C /C K = partition coefficient m aq P = permeability constant D = diffusion coefficient x = thickness of membrane (80 - 100 A) P = KD/x G = RT ln C 2 /C 1 Figure 2 Evidence for Protein-mediated Transport Permeability Coefficients of Natural and Synthetic Membranes to D-Glucose and D-Mannitol at 25 C Permeability Coefficients (cm/s) Membrane Preparation D-Glucose D-Mannitol Synthetic Lipid Bilayer Calculated Diffusion Intact Human RBC's 2.4 x 10 4.4 x 10 4.0 x 10 3.0 x 10 2.0 x 10 5.0 x 10-10-11-9-9-9-4 from Jung, C.Y. (1975) in The Red Blood Cell ed. D. Surgenor Vol 2, p709 Figure 3...
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This note was uploaded on 06/07/2011 for the course BCH 6206 taught by Professor Staff during the Spring '08 term at University of Florida.
- Spring '08