bio lecture 6. membrane transport

bio lecture 6. membrane transport - 8/31/2011 Membrane...

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8/31/2011 1 Membrane Transport Dr. Mark Holbrook Transport Across Membranes •Permeability of membrane •Osmosis •Water balance •Facilitated diffusion •Active transport •Electrochemical potential Membrane Permeability •Hydrophobic interior •Fat-soluble & non-polar molecules permeate o Hydrocarbons, O 2, CO2 •Polar & ionic molecules need special path o Channels, transporters Water (aquaporins) •Membrane is selectively permeable
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8/31/2011 2 Direction of movement Passive movement - high to low concentration – Diffusion, Osmosis, Facilitated Diffusion Active movement – low to high concentration (free or mediated by transporter, channel) energy (Z + from – to + environment) + + + + + + + + + + + + + - + Osmosis Osmosis is the diffusion of water across a selectively permeable membrane Concentration dependent – spontaneous movement from high to low concentration (of water ) [this will be from low to high concentration of dissolved molecules] H 2 O Selectively permeable membrane Lower concentration
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This note was uploaded on 10/11/2011 for the course BIO 010 taught by Professor Holbrook during the Spring '11 term at Iowa State.

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bio lecture 6. membrane transport - 8/31/2011 Membrane...

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