Membrane transport ppt BIOCHEMISTRY

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Membrane transport ppt BIOCHEMISTRY

  1. 1. Dr. Vijay Marakala, MBBS, MD. Assistant professor BIOCHEMISTRY SIMS & RC
  2. 2. • Cell membrane is the boundary between inside & outside… IN food carbohydrates sugars, proteins amino acids lipids salts, O2, H2O OUT waste ammonia salts CO2 H2O products IN OUT NO!
  3. 3. • Biological membrane are semipermeable Channel proteins Carrier proteins Lipid bilayer interstices
  4. 4. Passive transport Active transport
  5. 5. • Transport of solute molecules from across membrane • It is a down hill transport and requires no energy Simple diffusion Facilitated diffusion 2 types
  6. 6. • Move from HIGH to LOW concentration – “passive transport” – no energy needed Diffusion Through the channel protein and lipid bilayer interstices. E.g., Transport of O2, CO2, N2, ethanol and urea
  7. 7. Passive transport protein Lower concentration Higher concentration of Protein channel
  8. 8. E.g., Transport of glucose and most amino acids Through carrier protein conformational change
  9. 9. • Molecule moves . • Needs an external Primary active transport • Energy is derived directly from hydrolysis of ATP Secondary active transport • ATP provides the energy for transport indirectly Two types
  10. 10. Sodium-Potassium pump High Na+ Low Na+ Low K+ High K+
  11. 11. • ATP provides the energy for transport indirectly. • Uses an energy of an electrochemical gradient or membrane potential produced originally by primary active transport process by using ATP Co-transport or Symport Both the substances move across in same direction Sodium- glucose cotransport Counter transport or antiport Each substance moves in opposite direction Sodium-calcium counter transport
  12. 12. Voltage gated channels are opened by membrane depolarization Membrane potential change (voltage difference) switches the ion channel to open Voltage gated sodium channels Voltage gated potassium channels
  13. 13. ENDOCYTOSIS Pinocytosis (cellular drinking) Phagocytosis (cellular eating) EXOCYTOSIS Exocytic vesicles
  14. 14. Vesicle forming
  15. 15. Vesicle Fluid outside cell Protein Cytoplasm
  16. 16. • Water moves rapidly into & out of cells – evidence that there were water channels 1991 | 2003 Peter Agre John Hopkins Roderick MacKinnon Rockefeller

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