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Similar to 4. oxidative phosphorylation
4. oxidative phosphorylation
- 1.
- 2. Oxidative Phosphorylation This occursin the inner membranes of the mitochondria enzymes and protein carrier molecules embedded folded into cristae to increase the surface area
- 3. NAD reduced andFAD reduced are passed to ETC The Hydrogen atom is split into a proton (H+) and an electron (e-)
- 4. The proton remainsin solution The molecule that splits hydrogen moves the proton into the inter- membrane space The proton will later be used to reduce oxygen
- 5. The electron is transferredto various electron carriers along a biological electron transport chain At certain points ATP is made by phosphorylation – during chemiosmosis Oxygen is finally reduced to water
- 7. Biological electron transport Thisis a series of linked oxidation and reduction, or Redox, reactions a donor and an acceptor of electrons The acceptor gains an electron and becomes reduced The donor looses an electron and becomes oxidized Fe2+ + Cu2+ Fe 3+ + Cu+
- 8. Energy is lostas the electron is passed along the chain usually as heat At certain points there is enough energy to make ATP This is done by a process called Chemiosmosis
- 9. In the firststep NADreduced donates the hydrogen to a hydrogen carrier The first hydrogen carrier is now in the reduced state
- 10. The hydrogen isthen passed to a second hydrogen carrier molecule This is now reduced The first carrier is oxidised It can now pick up more hydrogen
- 11. It is atthis point that FAD can first donate hydrogen If FAD is being used the process begins here
- 12. The hydrogen isbroken into a proton and an electron The proton is released into the inter- membrane space because of the structure of the carrier molecule This will make a proton gradient across the inner membrane
- 13. An electron acceptormolecule picks up the electron and becomes reduced
- 14. The electron ispassed to a second electron carrier then to Cytochrome oxidase – which is now reduced
- 15. The final electronacceptor is oxygen Two electrons combine with a 2 protons to form 2 hydrogens These are picked up by oxygen, forming water
- 16. The final stepin oxidative phosphorylation involves cytochrome oxidase reducing oxygen to water. This step can be inhibited using Potassium Cyanide or Carbon monoxide These are known as respiratory inhibitors they can be used experimentally to show the effects of blocking respiration (energy release) on a process
- 17. The transfer ofelectrons makes energy available Some is lost as heat But at some points there is enough energy released to produce ATP Potentially each NADreduced can generate 3 ATP molecules And each NADreduced can generate 2 ATP molecules
- 19. In reality 25%of the energy made is used in transporting ATP out of the mitochondria therefore For each NAD reduced there are 2.5 ATP made For each FAD reduced there are 1.5 ATP made
- 20. process NAD reduced made FAD red made Amount ATP formed in ETC Total glycolysis2 - 2 x 2.5 = 5 Link reaction 1x2 - 2 x 2.5= 5 Krebs Cycle 3x2 1 x 2 6 x 2.5 = 3 x 1.5 = 15 3 TOTAL 28
- 21. Process ATP/glucose glycolysis -2+ 4 = 2 Link reaction - Krebs cycle 1 x 2 = 2 Oxidative phosphorylation 28 TOTAL 32
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- 23. the most acceptedexplanation for ATP synthesis during the electron transport chain Note that ATP formed in glycolysis and the Krebs cycle uses Chemical Potential energy from the bonds
- 24. Energy from theETC is used to pump hydrogen ions from the mitochondrial matrix to the space between the membranes of the envelope
- 25. This occurs becauseof the orientation of the proteins that pick up and then loose the hydrogen ions they will always transfer the ions to one side of the membrane
- 26. There are “stalkedparticles” that cross the inner membrane and act as both channels for the H+ ions to diffuse down their gradient, And as ATPsynthase molecules
- 27. For 3 H+ ionsmoving through the ATPsynthase one ADP is phosphorylated to ATP
- 28. Recommended videos ETC andATPsynthase Very good