ETCs

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electron transport chain by sunil shah (bond king) and groups..

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ETCs

  1. 1. Group – 3Shah Sunil and Groups
  2. 2. Respiration Respiration Involves : Glycolysis, Krebs cycle, Electron transport and Oxidative Phosphorylation
  3. 3. INTRODUCTION Glycolysis : Occurs in the cytoplasm. Breaks glucose into two molecules of pyruvate. Krebs cycle : occurs in the mitochondrial matrix. degrades pyruvate to carbon dioxide. Several steps in glycolysis and the Krebs cycle transfer electrons from substrates to NAD+, forming NADH. NADH passes these electrons to the electron transport chain.
  4. 4. Mitochondria stage 3rd of respiration Occurs in mitochondria.
  5. 5. Mitochondria Outer membrane- permeable to small molecules Inner membrane- electron transport ATP synthase Cristae increase area Integrity required for coupling ETS to ATP synthesis
  6. 6. Mitochondria outer membrane relatively permeable inner membrane permeable only to those things with specific transporters ◦ Impermeable to NADH and FADH2 ◦ Permeable to pyruvate Compartmentalization ◦ Krebs and β-oxidation in matrix ◦ Glycolysis in cytosol
  7. 7. Electron Transport System Electron Transport Chain – is a collection of molecules embedded in the inner membrane of the mitochondria ◦ Most components are proteins
  8. 8. Electron Transport System Mechanism the cell that converts the energy in NADH and FADH2 into ATP. Electrons flow along an energy gradient via carriers in one direction from a higher reducing potential to a lower reducing potential The ultimate acceptor is molecular oxygen. At the end of the chain electrons are passed to oxygen forming water.
  9. 9. Electron Transport System An NADH molecule begins the process by “dropping off” its electron at the first electron carrier molecule
  10. 10. ETS Remember: each component will be 50 NADH reduced when it accepts 40 I FADH2 FAD Multiprotein FMN complexes Free energy (G) relative to O2 (kcl/mol) the electron and oxidized Fe•S O Fe•S Cyt b II III when it passes the 30 Fe•S Cyt c1 Cyt c IV electron down to the more 20 Cyt a Cyt a3 electronegative carrier molecule in the chain 10 0 2 H ++ 12 O2 H2 O
  11. 11. Finally the electron is passed tooxygen, which is very electronegative. NADH 50 FADH2 I Multiprotein 40 FAD Free energy (G) relative to O2 (kcl/mol) FMN complexes Fe•S II The oxygen also picks Fe•S O Cyt b III Fe•S up 2 H+ ions from the 30 Cyt c1 Cyt c IV Cyt a aqueous solution and 20 Cyt a3 forms water 10 0 2 H ++ 12 O2 H2 O
  12. 12. ETS FADH goes through 50 NADH mostly the same FADH2 Multiprotein Free energy (G) relative to O2 (kcl/mol) 40 I FAD processes, except it FMN complexes Fe•S Fe•S II O III Cyt b drops off its electron 30 Fe•S Cyt c1 Cyt c IV at a lower point on Cyt a Cyt a3 20 the ETC 10 0 2 H ++ 12 O2 H2O
  13. 13. The ETC makes no ATP directly!The ETC releases energy in a step-wise series of reactionsIt powers ATP synthesis via oxidativephosphorylation.But it needs to be coupled withchemiosmosis to actually make ATP.
  14. 14. Oxidative PhosphorylationProduction of ATP usingtransfer of electrons for energy Some ATP is produced by substrate-level phosphorylation during glycolysis and the Krebs cycle, but most comes from oxidative phosphorylation
  15. 15. Oxidative phosphorylation CONCEPT : During oxidative phosphorylation, chemiosmosis couples electron transport to ATP synthesis
  16. 16. Chemiosmosis The Energy-Coupling Mechanism Inner membrane of mitochondria has many protein complexes called ATP synthase ◦ ATP synthase – enzyme that makes ATP from ADP and inorganic phosphate It uses the energy of an existing gradient to do this.
  17. 17. The existing gradient is the difference in H+ ion concentration on opposite sides of the inner membrane of the mitochondria Inner Mitochondrial Oxidative Glycolysis phosphorylation. membrane electron transport and chemiosmosis ATP ATP ATP H+ H+ H+ H+ Protein complex Cyt cIntermembrane of electronspace carners Q IV I III ATPInner II synthasemitochondrial FADH2 FAD+ 2 H+ + 1/2 O2 H2Omembrane NADH+ NAD+ ADP + Pi ATP (Carrying electrons from, food) H+Mitochondrial Electron transport chain Chemiosmosismatrix Electron transport and pumping of protons (H +), ATP synthesis powered by the flow which create an H+ gradient across the membrane Of H+ back across the membrane Oxidative phosphorylation
  18. 18. Chemiosmosis Chemiosmosis – the process in which energy stored in the form of a hydrogen ion gradient across a membrane is used to drive cellular work (like the synthesis of ATP)
  19. 19.  It is the job of the ETC to create this H+ ion gradient Inner Mitochondrial Oxidative Glycolysis phosphorylation. membrane electron transport and chemiosmosis ATP ATP ATP H+ H+ H+ H+ Protein complex Cyt cIntermembrane of electronspace carners Q IV I III ATPInner II synthasemitochondrial FADH2 FAD+ 2 H+ + 1/2 O2 H2Omembrane NADH+ NAD+ ADP + Pi ATP (Carrying electrons from, food) H+Mitochondrial Electron transport chain Chemiosmosismatrix Electron transport and pumping of protons (H+), ATP synthesis powered by the flow which create an H+ gradient across the membraneOf H+ back across the membrane Oxidative phosphorylation
  20. 20. H+ ions are pumped into theintermembrane space by the ETCThe H+ ions want to drift back into thematrix.But they can only come into the matrixeasily through ATP synthase channels
  21. 21. A protein complex, ATPsynthase, in the cristaeactually makes ATP fromADP and Pi.ATP used the energy ofan existing proton gradientto power ATP synthesis. proton gradientdevelops between theintermembrane spaceand the matrix.
  22. 22. Mitochondrial redox carrierNADH Complex I Q Complex III Complex IIComplex IV FADHO2
  23. 23. 4 Complexes proteins in specific order Transfers 2 electrons in specific order ◦ Proteins localized in complexes  Embedded in membrane  Ease of electron transfer ◦ Electrons ultimately reduce oxygen to water  2 H+ + 2 e- + ½ O2 -- H2O
  24. 24. Complex I Has NADH binding site ◦ NADH reductase activity  NADH - NAD+ ◦ transfers to electron carriers ◦ NADH (nicotinamide adenine dinucleotide )
  25. 25. Passes them to coenzyme Q ( Ubiquinone )Also receive electron from complex II
  26. 26. Complex II succinate ---FAD—ubiquinone ◦ Contains coenzyme Q ◦ FADH2 binding site  FAD reductase activity  FADH2 -- FAD  conversion of succinate to fumerate
  27. 27. Mitochondrial redoxcarriers
  28. 28. Complex III ubiquinone - ubiquinone while cytochrome C gets reduced Also contains cytochromes b NADH generates more energy than FADH2
  29. 29. Complex IV reduction of oxygen cytochrome oxidase oxygen ---> water ◦ 2 H+ + 2 e- + ½ O2 -- 2 H2O ◦ transfers e- one at a time to oxygen
  30. 30. ATP Produced◦ The NADH from glycolysis may also yield 3ATP. Krebs cycle can be used to generate about 2ATP. Electron transport chain yield 32 ATP.
  31. 31. ATP Produced About 40% of energy glucose moleculetransferred to ATP during cellular respiration Makes approximately 38 ATP.
  32. 32. Conclusion /ResultOVERALL yield fromglucose 36-38 ATPs
  33. 33. THANK YOUGROUP -3SHAH SUNIL KUMARGIRI JEMYTIMILSINA BINODMAJHI INDRAABDHIKINIWARSAMEMOHAMMAD ABDIKALI

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