01 cellular respiration-2010 update


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  • Recap what was in the TVO video. - two conditions under which glucose can be metabolised
  • Think entropy!!!
  • Recall from video
  • 01 cellular respiration-2010 update

    1. 3. Cellular Respiration <ul><li>In the presence of oxygen: </li></ul><ul><li>aerobic cellular respiration </li></ul><ul><li>In the absence of oxygen: </li></ul><ul><li>alcoholic fermentation (yeast) </li></ul><ul><li>lactic acid fermentation (humans) </li></ul>
    2. 4. Goals of Cellular Respiration <ul><li>To break 6-carbon glucose down and release 6 molecules of CO 2 </li></ul><ul><li>Move glucose electrons to O 2 , and combine with H + ions to form 6 molecules of H 2 O </li></ul><ul><li>Collect energy in the form of ATP </li></ul>
    3. 5. Four Major Stages <ul><li>Glycolysis </li></ul><ul><li>Oxidative decarboxylation (pyruvate oxidation) </li></ul><ul><li>Krebs cycle </li></ul><ul><li>Electron Transport Chain (oxidative phosphorylation / OXPHOS) </li></ul><ul><li>cytoplasm </li></ul><ul><li>mitochondrial matrix </li></ul><ul><li>mitochondrial matrix </li></ul><ul><li>inner mitochondrial membrane </li></ul>
    4. 6. Four Major Stages
    5. 7. Glycolysis
    6. 8. Glycolysis <ul><li>http://www.youtube.com/watch?NR=1&v=VQi3uKN1VVw </li></ul><ul><li>http://www.youtube.com/watch?v=bXScgXleLX8&feature=related </li></ul><ul><li>glycolysis – breaking down glucose molecules </li></ul><ul><li>Specifically, glucose (6 carbon molecule) is broken down into the final product of two pyruvate molecules (3 carbon molecule) </li></ul><ul><li>glycolysis activity </li></ul>
    7. 9. Glycolysis
    8. 10. Glycolysis: What to know! <ul><li>What is the purpose of each step? </li></ul><ul><li>What type of reaction is happening? </li></ul><ul><li>What type of enzyme is used? (NOT THE ENZYME NAME!) </li></ul><ul><li>Energy distribution at each step. </li></ul>
    9. 11. Glycolysis: Two major phases <ul><li>investment phase – energy (ATP) used up to split the molecule </li></ul><ul><ul><li>steps 1 through 5 </li></ul></ul><ul><li>pay-off phase – energy molecules (ATP and NADH) are produced </li></ul><ul><ul><li>steps 6 through 10 </li></ul></ul>
    10. 12. Glycolysis: Step by Step <ul><li>Step 1: </li></ul><ul><li>carbon 6 phosphorylated using ATP to prevent glucose from leaving the cell </li></ul><ul><li>rxn type: phosphorylation </li></ul><ul><li>enzyme: kinase </li></ul><ul><li>energy: absorbed </li></ul>
    11. 13. Glycolysis: Step by Step <ul><li>Step 2: </li></ul><ul><li>atoms of molecule are rearranged </li></ul><ul><li>rxn type: isomerization </li></ul><ul><li>enzyme: isomerase </li></ul><ul><li>energy: equilibrium </li></ul>
    12. 14. Glycolysis: Step by Step <ul><li>Step 3: </li></ul><ul><li>carbon 1 phosphorylated to cause the molecule to be energetically unstable </li></ul><ul><li>rxn type: phosphorylation </li></ul><ul><li>enzyme: kinase </li></ul><ul><li>energy: absorbed </li></ul>
    13. 15. Glycolysis: Step by Step <ul><li>Step 4: </li></ul><ul><li>the unstable molecule is split into two molecules </li></ul><ul><li>rxn type: cleavage </li></ul><ul><li>enzyme: lyase </li></ul><ul><li>energy: equilibrium </li></ul>
    14. 16. Glycolysis: Step by Step <ul><li>Step 5: </li></ul><ul><li>DHAP and G3P are isomers </li></ul><ul><li>G3P is used in many other metabolic pathways </li></ul><ul><li>rxn type: isomerization </li></ul><ul><li>enzyme: isomerase </li></ul><ul><li>energy: equilibrium </li></ul>only glyceraldehyde-3-phosphate will continue to be used in glycolysis
    15. 17. Glycolysis: Step by Step <ul><li>Step 6: </li></ul><ul><li>NADH (energy molecule) is created </li></ul><ul><li>rxn type: redox </li></ul><ul><ul><ul><ul><ul><li> phosphorylation </li></ul></ul></ul></ul></ul><ul><li>enzyme: dehydrogenase </li></ul><ul><li>Serves two functions in this step. </li></ul><ul><li>First the enzyme transfers a hydride ion (H-) from glyceraldehyde phosphate to the oxidizing agent nicotinamide adenine dinucleotide (NAD+) to form NADH. </li></ul><ul><li>Next dehydrogenase adds a phosphate (P) from the cytosol to the oxidized glyceraldehyde phosphate to form 1, 3-Bisphosphoglycerate. </li></ul><ul><li>energy: released </li></ul>
    16. 18. NAD + / NADH <ul><li>NAD + – nicotinamide adenine dinucleotide (oxidized form) </li></ul><ul><li>NADH – nicotinamide adenine dinucleotide (reduced form) </li></ul>
    17. 19. Glycolysis: Step by Step <ul><li>Step 7: </li></ul><ul><li>ADP phosphorylation to create ATP </li></ul><ul><li>rxn type: substrate-level phosphorylation </li></ul><ul><li>enzyme: kinase </li></ul><ul><li>energy: released </li></ul>
    18. 20. Glycolysis: Step by Step <ul><li>Step 8: </li></ul><ul><li>phosphate moved from carbon 3 to carbon 2 </li></ul><ul><li>rxn type: isomerization </li></ul><ul><li>enzyme: isomerase </li></ul><ul><li>energy: equilibrium </li></ul>
    19. 21. Glycolysis: Step by Step <ul><li>Step 9: </li></ul><ul><li>water removed to set up next reaction </li></ul><ul><li>rxn type: dehydration </li></ul><ul><li>enzyme: lyase </li></ul><ul><li>energy: released </li></ul>
    20. 22. Glycolysis: Step by Step <ul><li>Step 10: </li></ul><ul><li>ADP phosphorylation to ATP </li></ul><ul><li>rxn type: substrate-level phosphorylation </li></ul><ul><li>enzyme: kinase </li></ul><ul><li>energy: released </li></ul>
    21. 23. Glycolysis Summary <ul><li>glucose  2 pyruvate </li></ul><ul><li>net 2 ATP molecules produced </li></ul><ul><ul><li>2 used; 4 generated </li></ul></ul><ul><li>2 NADH molecules produced </li></ul>
    22. 24. Two Methods of ATP formation <ul><li>substrate-level phosphorylation </li></ul><ul><li>oxidative phosphorylation (OXPHOS) </li></ul><ul><li>direct ATP formation through phosphate transfer from substrate to ADP </li></ul><ul><li>indirect ATP formation through redox reactions involving O 2 as a final electron acceptor </li></ul>glycolysis & Kreb cycle electron transport chain
    23. 25. <ul><li>http://www.youtube.com/watch?v=6JGXayUyNVw </li></ul><ul><li>http://www.youtube.com/watch?v=YyN0wx2AHfE&feature=related </li></ul><ul><li>http://www.youtube.com/watch?v=DJrA64rBhSk </li></ul><ul><li>http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__how_glycolysis_works.html </li></ul>
    24. 27. Aerobic Metabolism <ul><li>NADH and pyruvate will continue through Kreb cycle and the ETC to synthesize ATP only in the presence of O 2 . </li></ul><ul><li>In the absence of O 2 , cells still want to try to make as much energy as possible using only glycolysis. </li></ul>
    25. 28. Anaerobic Metabolism <ul><li>Two types: </li></ul><ul><li>lactic acid fermentation (humans) </li></ul><ul><li>alcohol fermentation (yeast) </li></ul>
    26. 29. Lactic Acid Fermentation <ul><li>In the absence of O 2 , lactate dehydrogenase converts pyruvate into lactic acid in humans. </li></ul><ul><ul><li>lactic acid ( lactate ) is a 3 carbon molecule </li></ul></ul><ul><li>NADH is converted back into NAD + for glycolysis to continue to occur. </li></ul><ul><li>Once enough O 2 has returned to the cells, lactic acid is converted back into pyruvate. </li></ul>
    27. 30. Lactic Acid Fermentation Need to replenish supply of NAD+. Why is this important?
    28. 31. Glycolysis
    29. 32. Alcohol Fermentation <ul><li>In the absence of O 2 : </li></ul><ul><li>pyruvate is decarboxylated (loss of CO 2 ) into acetaldehyde </li></ul><ul><li>alcohol dehydrogenase converts acetaldehyde into ethanol </li></ul><ul><li>NADH is converted back into NAD+ for glycolysis to continue to occur. </li></ul><ul><li>Ethanol will not be converted back to pyruvate even if O 2 concentration has increased </li></ul>
    30. 33. Alcohol Fermentation
    31. 34. Anaerobic Fermentation Summary <ul><li>lactic acid fermentation </li></ul><ul><ul><li>2 pyruvate  2 lactic acid </li></ul></ul><ul><ul><li>NADH  NAD + </li></ul></ul><ul><li>alcohol fermentation </li></ul><ul><ul><li>2 pyruvate  2 acetylaldehyde  2 ethanol </li></ul></ul><ul><ul><li>2 CO 2 released </li></ul></ul><ul><ul><li>NADH  NAD + </li></ul></ul>