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Cellstructure& Genetic Control

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Cellstructure& Genetic Control

  1. 1. Bioenergetics and Glycolysis Getting the E out of C www.freelivedoctor.com
  2. 2. Energy Transfer follows thermodynamic laws <ul><li>Gibbs helmholtz </li></ul><ul><ul><li>Δ G = Δ H – T Δ S </li></ul></ul><ul><ul><ul><li>Enthalpy </li></ul></ul></ul><ul><ul><ul><li>Entropy </li></ul></ul></ul><ul><ul><ul><ul><li>Remember Δ S universe > 0 is a spontaneous process </li></ul></ul></ul></ul><ul><ul><ul><li>Overall if Δ G < 0 the process is spontaneous </li></ul></ul></ul><ul><li>Δ G = -RTlnK </li></ul><ul><ul><li>Relates Δ G to equilibrium </li></ul></ul><ul><li>Δ G are additive </li></ul><ul><ul><ul><li>State function </li></ul></ul></ul><ul><ul><ul><li>Overall Δ G has to be – for a process to be spontaneous </li></ul></ul></ul>www.freelivedoctor.com
  3. 3. Le Chatelier’s Principle and Δ G <ul><li>Remember Le Chatelier and affect on equilibrium </li></ul><ul><ul><li>If one reaction has a positive Δ G, but the next reaction, which is in equilibrium has a negative Δ G , the first reaction can be pulled through </li></ul></ul><ul><ul><li>Many examples of this in glycolysis </li></ul></ul>www.freelivedoctor.com
  4. 4. ATP (Adenosine Tri-Phosphate) www.freelivedoctor.com
  5. 5. Hydrolysis of ATP ATP ------  ADP + Pi + 7.3 kcal www.freelivedoctor.com
  6. 6. Energy from ATP hydrolysis <ul><li>7.3 kcal /mol (30.5 kJ/mol for you SI nuts) </li></ul><ul><li>Energy from: </li></ul><ul><ul><li>Separation of negative charges </li></ul></ul><ul><ul><li>Increased entropy </li></ul></ul><ul><ul><ul><li>Phosphate now free…2 thing instead of one </li></ul></ul></ul><ul><ul><li>Resonance stabilization of phosphate </li></ul></ul>www.freelivedoctor.com
  7. 7. Other Energy sources <ul><li>Hydrolysis of thioester </li></ul><ul><ul><li>Resonance stabilization of carboxylate </li></ul></ul><ul><ul><li>Energy released from group transfer, not simply hydrolysis </li></ul></ul><ul><ul><li>Coenzyme A (CoA) is an important thiol that forms thioesters </li></ul></ul>www.freelivedoctor.com
  8. 8. Coenzyme A www.freelivedoctor.com
  9. 9. Redox <ul><li>Review: </li></ul><ul><ul><li>Electron transfer reactions </li></ul></ul><ul><ul><li>Energy from electron transfer </li></ul></ul><ul><ul><li>Δ G = -nFE </li></ul></ul><ul><ul><li>Electrons typically transferred to a carrier </li></ul></ul><ul><ul><ul><li>NAD + + 2 e - + 2H + -  NADH + H + </li></ul></ul></ul><ul><ul><ul><li>FAD + 2 e - + 2H + -  FADH 2 </li></ul></ul></ul><ul><ul><ul><li>Electrons transferred later for ATP generation </li></ul></ul></ul>www.freelivedoctor.com
  10. 10. NAD (Nicotinamide Adenine Dinucleotide) www.freelivedoctor.com
  11. 11. Reduction of NAD + on Nicotinamide Ring www.freelivedoctor.com
  12. 12. FAD (Flavin Adenine Dinucleotide) www.freelivedoctor.com
  13. 13. Reduction of Flavin Ring on FAD www.freelivedoctor.com
  14. 14. Glycolysis <ul><li>In Cytosol </li></ul><ul><li>Anaerobic </li></ul><ul><li>Breakdown of glucose to two pyruvate molecules </li></ul><ul><ul><li>Glucose + 2 ADP + 2 Pi + 2 NAD + -  2 pyruvate + 2 ATP + 2 NADH + 2 H + </li></ul></ul><ul><ul><li>C 6 H 12 O 6 + 2 ADP + 2 Pi + 2 NAD + -  2 C 3 H 3 O 3 - + 2 ATP + 2 NADH + 2 H + </li></ul></ul>www.freelivedoctor.com
  15. 15. Glycolysis www.freelivedoctor.com
  16. 16. Hexokinase reaction <ul><li>Irreversible </li></ul><ul><li>Kinase (phosphate transfer) </li></ul><ul><li>-16.7kJ </li></ul>www.freelivedoctor.com
  17. 17. Hexose phosphate isomerase reaction <ul><li>Keto-aldol isomerization </li></ul><ul><ul><li>Glucose to fructose </li></ul></ul><ul><li>1.7 kJ </li></ul>www.freelivedoctor.com
  18. 18. Phosphofructokinase reaction <ul><li>Same as hexokinase reaction </li></ul><ul><li>-14.2kJ </li></ul><ul><li>Major point of regulation </li></ul><ul><ul><li>Committed step </li></ul></ul><ul><ul><li>Stimulated by ADP and AMP </li></ul></ul><ul><ul><li>Inhibited by ATP and fatty acids </li></ul></ul>www.freelivedoctor.com
  19. 19. Aldolase Reaction <ul><li>Reverse aldol condensation </li></ul><ul><li>23.8kJ </li></ul><ul><li>Makes 2 3-Carbon molecules </li></ul>www.freelivedoctor.com
  20. 20. Triose phosphate isomerase <ul><li>Keto-enol isomerization (like hexose phosphate isomerase reaction) </li></ul><ul><li>7.5kJ </li></ul><ul><li>Net is 2 glyceraldehyde – 3 – phosphate </li></ul><ul><li>From now on each reaction times 2 </li></ul>www.freelivedoctor.com
  21. 21. Glyceraldehyde -3-phosphate dehydrogenase <ul><li>Oxidation coupled to phosphorylation </li></ul><ul><li>Makes NADH </li></ul><ul><li>6.3kJ </li></ul><ul><li>(remember X 2) </li></ul>www.freelivedoctor.com
  22. 22. Phosphoglycerate Kinase <ul><li>Phosphate transfer </li></ul><ul><ul><li>Substrate level phosphorylation </li></ul></ul><ul><li>Driven by stabilization of carboxylate </li></ul><ul><li>-18.5kJ </li></ul><ul><li>Pulls previous reactions through </li></ul>www.freelivedoctor.com
  23. 23. Phosphoglycerate mutase <ul><li>Moves from 3 -  2 </li></ul><ul><li>2 steps </li></ul><ul><ul><li>Makes 2,3 </li></ul></ul><ul><ul><li>Removes 3 </li></ul></ul><ul><li>4.4kJ </li></ul>www.freelivedoctor.com
  24. 24. enolase <ul><li>Makes unstable enol intermediate </li></ul><ul><li>7.5 kJ </li></ul>www.freelivedoctor.com
  25. 25. Pyruvate kinase <ul><li>Last reaction….woohoo </li></ul><ul><li>Substrate level phosphorylation </li></ul><ul><li>Stabilization of enol -  keto </li></ul><ul><li>-31.4kJ </li></ul>www.freelivedoctor.com
  26. 26. Net products from Glycolysis (per glucose) <ul><li>2 pyruvate </li></ul><ul><li>2 NADH </li></ul><ul><li>2 ATP </li></ul><ul><li>Total energy = -61.3 kJ </li></ul><ul><ul><li>Sum of energies </li></ul></ul>www.freelivedoctor.com
  27. 27. Fates of pyruvate www.freelivedoctor.com
  28. 28. Fates of Pyruvate <ul><li>Depend on organism and conditions </li></ul><ul><li>Yeast </li></ul><ul><ul><li>Anaerobic </li></ul></ul><ul><ul><ul><li>Pyruvate decarboxylase </li></ul></ul></ul><ul><ul><ul><li>Makes alcohol </li></ul></ul></ul><ul><ul><li>Aerobic </li></ul></ul><ul><ul><ul><li>Makes acetyl CoA ---  energy or fat </li></ul></ul></ul><ul><li>Others </li></ul><ul><ul><li>Anaerobic </li></ul></ul><ul><ul><ul><li>LDH </li></ul></ul></ul><ul><ul><ul><li>Makes lactate </li></ul></ul></ul><ul><ul><ul><li>Sore muscles </li></ul></ul></ul><ul><ul><li>Aerobic </li></ul></ul><ul><ul><ul><li>Acetyl Co A ---  energy or fat </li></ul></ul></ul>www.freelivedoctor.com
  29. 29. Glycogen www.freelivedoctor.com
  30. 30. Glycogenolysis www.freelivedoctor.com
  31. 31. Glycogen breakdown <ul><li>Glycogen phosphorylase breaks down alpha 1,4 linkages </li></ul><ul><ul><li>Makes glucose-1-phosphate </li></ul></ul><ul><ul><li>Enzyme changes to glucose-6-phosphate and enters glycolysis there </li></ul></ul><ul><li>Can’t break 1,6 linkages </li></ul><ul><ul><li>Debranching enzyme breaks 1,6 (when 4 sugars away from branch) and adds to end </li></ul></ul><ul><ul><li>Glycogen phosphorylase takes over and breaks down the rest </li></ul></ul>www.freelivedoctor.com
  32. 32. Other sugars <ul><li>Fructose </li></ul><ul><ul><li>Comes in at fructose-6-p and immediately phosphorylated </li></ul></ul><ul><ul><ul><li>Lipogenic…after branch to glycogen…makes acetyl CoA </li></ul></ul></ul><ul><li>Lactose </li></ul><ul><ul><li>Glucose and galactose </li></ul></ul><ul><ul><ul><li>Galactose </li></ul></ul></ul><ul><ul><ul><ul><li>Epimerase turns into glucose-6-P and enters there </li></ul></ul></ul></ul>www.freelivedoctor.com
  33. 33. gluconeogenesis <ul><li>Making glucose from pyruvate </li></ul><ul><ul><li>In liver </li></ul></ul><ul><ul><li>Uses same enzymes as glycolysis except where nonequilibrium reactions </li></ul></ul><ul><ul><li>Uses NADPH instead of NADH </li></ul></ul>www.freelivedoctor.com

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