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Membrane transport

Membrane transport. Biology 1. Molecules move from high to low. Diffusion move from HIGH to LOW concentration. Diffusion. Move from HIGH to LOW concentration passive transport no energy needed. diffusion of water. diffusion. osmosis. Simple Diffusion (through the cracks) .

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Membrane transport

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  1. Membrane transport Biology 1

  2. Molecules move from high to low • Diffusion • move from HIGH to LOW concentration

  3. Diffusion • Move from HIGH to LOW concentration • passive transport • no energy needed diffusion of water diffusion osmosis

  4. Simple Diffusion (through the cracks) • Move from HIGH to LOW fat fat fat Which way will fat move? inside cell fat fat fat LOW HIGH fat outside cell fat fat fat fat fat fat fat

  5. Q: What kind of molecules can move directly through bilayer by simple diffusion? • Small gasses (O2, CO2)-through the cracks • Lipids (non-polar stuff)- same as membrane • Q2: What if you have a polar molecule? Like water?????

  6. Facilitated Diffusion (bouncer) • Move from HIGH to LOWthrough a channel sugar sugar sugar sugar inside cell sugar sugar LOW Which way will sugar move? HIGH outside cell sugar sugar sugar sugar sugar sugar sugar

  7. inside cell inside cell outside cell outside cell Simple vs. facilitated diffusion simple diffusion facilitated diffusion lipid H2O protein channel H2O

  8. Q3: What polar molecules use facilitative diffusion? • Water (osmosis is facilitative diffusion through “Aquaporins”) • Glucose • Salts/ions (Cl-, K+, Na+, H+, Ca+)

  9. Active transport (the doorman) • Cells may need molecules to move against concentration “hill” • need to pump “uphill” • from LOW to HIGHusing energy • protein pump • requires energy • ATP ATP

  10. Transport summary simplediffusion facilitateddiffusion ATP activetransport

  11. Bulk transport • Moves LARGE GROUPS of molecules or chunks of food/waste in or out of a cell membrane. • Too big for proteins alone • Requires energy • 2 Types: • Endocytosis (move stuff up “en-der”) • Exocytosis (move stuff out, exit)

  12. Endocytosis- cellular feeding • You ingest food and water, cells do too! • Types ofENDOcytosis: • 1) Phagocytosis= “cellular eating” • 2) Pinocytosis= “cellular drinking” • Check out the video clips on endocytosis • http://www.youtube.com/watch?v=qpw2p1x9Cic Omm Nom Nom

  13. Exocytosis • Materials exit the cell in bulk (signals, wastes) • Vesicle forms around materials inside cell • Fuses with membrane • Empties contents on the other side!

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