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metal ions transport

Publié dans : Sciences
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Outlines

  1. 1. Metal Ion Transport and Storage
  2. 2. Inorganic chemistry • By Anwish Nawaz Abbasi Bilal Qadeer Kyani Muhammad Ahmed ALI Hamza Tariq
  3. 3. Outlines • Metal Ions Bioavailability • General Properties of Transport Systems. • Mechanisms of metal ion storage & resistance. • Specific Metal Ions K / Na Fe Ca • Problems of Metal Ion Transport.
  4. 4. Introduction • Chemical Properties. • Catalyze oxidation & reduction. • Act as Lewis acid in hydrolytic enzymes. eg: Zn • Structural Cofactor. • Problems. • Genetic diseases.
  5. 5. Metal Ion Bioavailability. • Bioavailability term implies more than just the incidence of an element on Earth and includes its prevalence in environment where life is found. Nickel in the Earth's core. Zinc sulfide in the biosphere. Molybdenum in the ocean
  6. 6. Bioavailability. • Fe is fourth most abundant element in Earth’s crust. • For mammalian cells, the source of metal ions is the blood plasma.
  7. 7. General properties of transport systems.
  8. 8. Ionophores •special carrier molecules that wrap around •metal ions. •Pass through the membrane by diffusion.
  9. 9. Ion Channels •Large pores in membrane. •Allow to movement of substrate across by diffusion
  10. 10. Ion pumps Molecules using energy to transport ions in one direction through a membrane. Primary active transport system.
  11. 11. Carriers •Bind to substrate on one side of membrane. •Confrmatinal change. •Release the substrate on opposite side of membrane.
  12. 12. Mechanisms for membrane Transport • Passive Transport : • Movement of ions • Due to concentration gradient. • Requiring no energy source. • Ionophores • , Ion channels. • Active Transport : • Movement of ions. • Against the concentration gradient. • Requiring energy from ATP hydrolysis. • Ion pumps.
  13. 13. Mechanisms of metal ion storage & resistance • Organisms store metal ions. • It have more benefits. • Allow the accumulation of high intacellularLebels of metal ions without the toxic. • Understood • mechanisof metal ion storage are, Ferritin Metallothionein
  14. 14. Ferritin
  15. 15. Metallothionein
  16. 16. Metallothionein cytopalmic • metal • binding protein. • Involved in ion storage & detoxification. • Small ,cysteinerich proteins that bind Zn2+,Cd2+ Cu2+ & cysligands • Found in cyanobacteria,fungi,plants,insects &vertebrates. • Bind metal ions with high affinity.
  17. 17. Sodium Na+ • Major • cationin human body • Important for • membrane function • Nerve impulses • Muscle contraction • Prevent blood clotting • Present in stomach walls, gallbladder and
  18. 18. Potassium K+ • Important for • Membrane function • Maintaining osmotic balance • Cofactor in photosynthesis and respiration
  19. 19. Sodium &Potassium Concentration of [Na+] &[K+] –nside red blood cells [Na+] =0.01M [K+] =0.09M–Outside red blood cells[Na+] =0.16M [K+] =0.01M • Ion pump is required to maintain concentration gradient • Also • Ionphore • Ion channel are used for Na & K ion transport
  20. 20. Sodium &Potassium pump
  21. 21. Selectivity of the process Depends upon • Differences in ionic radii. • Coulomb forces • Bases stronger than H2O bind preferentially to the hard acid Na • Bases weaker than H2O –bind preferentially to the hard acid K
  22. 22. Calcium Present in bones, enamel, shells • Important for • Signal pathways • Skeletal material • Maintaining potential difference across membranes • Concentration • Outside cell = 0.001M • Inside cell = 10-7 M
  23. 23. Calcium Regulaton. Ca is in cytoplasm. • pumped in to sarcoplasmicreticulum (A form of endoplasmic reticulum) • Up to 0.03M • Inside SR Ca is bound by calsequestrin • Hormone induced ion channels releases Ca from SR to muscle cell • Muscle contraction is triggered by sudden release of Ca
  24. 24. Calcium pump
  25. 25. Transport & storage problems. Capture of trace ions from the environment • Control the concentration. • Bulk ones present in high concentration. • Trace ones actively accumulated &insoluble. • Selectivity of ion uptake is essential. • Toxic ions excluded. • Beneficial ions accumulated. • Specialized molecules have evolved.
  26. 26. Transport & storage problems Charged ions pass through a Hydrophobic Membrane. • Neutral gases & low charge density ions move directly but high charge density require help. • Metal ions transport to their location for use & storage. • Release from ligand & storage require additional molecules.

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