4 5-microbial nutrition and culture


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4 5-microbial nutrition and culture

  1. 1. Chapter 5 Microbial Nutrition and Culture<br />Siti Sarah Jumali (ext 2123)<br />Room 3/14<br />sarah_jumali84@hotmail.com<br />
  2. 2. Groups of bugs based on energy capture and carbon source<br />AUTOTROPHY: Use carbon dioxide to synthesize organic molecules<br />Two types:<br />Photoautotrophs: obtain energy from light<br />Chemoautotrophs: obtain energy from oxidizing simple inorganic substance<br />
  3. 3. Groups of bugs based on energy capture and carbon source cont’d<br />HETEROTROPHY: Get carbon dioxide from ready made organic molecules<br />Two types:<br />Photoheterotrophs: obtain chemical energy from light<br />Chemoheterotrophs: obtain energy from breaking down ready-made organic compounds<br />
  4. 4. The main types of energy capturing Metabolism<br />
  5. 5. Examples of Energy Source<br />
  6. 6. Photosynthesis and Respiration<br />
  7. 7. Metabolism<br />The sum of all chemical processes carried out by living organisms<br />Anabolism: rxn that requires energy in order to synthesize complex molecules from the simpler ones <br />- (use energy and building blocks to build large molecules)<br />Catabolism: rxn that releases energy by breaking complex molecules into simpler ones which can be reused as building blocks<br />- (provides energy and building blocks for anabolism)<br />
  8. 8. Metabolism: The sum of catabolism and anabolism<br />Catabolism<br />Energy<br />Anabolism<br />
  9. 9. Metabolic Pathway<br />Glycolisis, fermentation, aerobic respiration and photosynthesis each consists of a series of chemical reaction<br />The product of one reaction serves as the substrate for the next: ABCD<br />Such chain of reactions is called a metabolic pathway:<br />- Anabolic pathways make the complex molecules that form structure of cells, enzymes and molecules that control cells<br />- Catabolic pathways capture energy in a form a cell can use<br />
  10. 10. Oxidation-Reduction Reactions<br />All catabolic reactions involve electron transfer which is directly related to oxidation and reduction (redox potential)<br />Redox reaction: An oxidation reaction paired with a reduction reaction<br /> - Oxidation: the loss of removal of electrons<br /> -Reduction: the gain of electrons<br />
  11. 11. Oxidation-Reduction Reactions<br />
  12. 12. Representative Biological Oxidations<br />In biological systems, the electrons are often associated with hydrogen atoms. Biological oxidations are often dehydrogenation.<br />Acronyms for oxidation and reduction: <br /><ul><li>Oxidation Is Losing Electrons, Reduction Is Gaining Electrons: OIL RIG
  13. 13. Losing Electrons Oxidation, Gaining Electrons Reduction: LEO the lion. GER! or LEO says GER
  14. 14. Electron Loss Means Oxidation: ELMO</li></li></ul><li>13<br />Metabolic Pathways of Energy Production<br />
  15. 15. Metabolic Pathways of Energy Production<br />(b)<br />
  16. 16. Carrier molecules such as Cytochrome (cyt) and some coenzymes carry energy in the form of electrons in many biochemical reactions<br />Coenzymes such as FAD carry whole hydrogen atoms (electrons together with protons); NAD carries one hydrogen atom and one “naked” electron<br />When co-enzymes are reduced, they increase in energy, when they are oxidized, they decrease in energy.<br />Energy Transfer by Carrier Molecules<br />
  17. 17. Energy Generation of ATP<br />ATP is generated by the phosphorylation of ADP<br /> ADP + Pi + Energy ATP<br /><ul><li>In cells, energy is provided by the hydrolysis of ATP</li></ul> ATP ADP + Pi + Energy<br />Energy<br />Energy<br />
  18. 18. Generation of ATP<br />Substrate level Phosphorylation: Energy from the transfer of a high energy PO4 to ADP generates ATP<br /> C-C-C-P + ADP C-C-C + ATP<br />Oxidative Phosphorylation: Energy relseased from transfer of electrons (oxidation) of one compound to another (reduction) is used to generate Atp in the electron transport chain<br />Photophosporylation: Light causes chlorophyll to give up electrons. Energy released from transfer of electrons (oxidation) of chlorophyll trough a system of carrier molecules is used to generate ATP<br />
  19. 19. Overview of Respiration vs Fermentation<br />
  20. 20.
  21. 21. Carbohydrate Catabolism<br />The breakdown of carbohydrate to release energy involves<br />Glycolisis (cytoplasm)<br />Krebs cycle (mitochondrion)<br />Electron transport chain<br />
  22. 22. Glycolysis<br />Glycolysis (Embden Meyerhof pathway) is the metabolic pathway used by most autotrophic and heterotrophic organismsm to begin breakdown of glucose<br />Does not require oxygen, but occur in precense or absence of oxygen<br />Overall chemical reaction of Glycolysis<br />
  23. 23.
  24. 24. 23<br />Glycolysis: Oxidation of Glucose<br />Glucose<br /> 2ATP<br /> 2 NAD+<br /> 2ADP 2NADH + 2H+<br /> 4 ADP<br /> 4 ATP<br />two Glyceraldehyde-3-PO4<br />two Pyruvate<br />
  25. 25. Glycolysis: Oxidation of Glucose<br />24<br />
  26. 26. Glycolysis: Oxidation of Glucose<br /> 2 NAD+ 2 NADH + 2 H+<br />25<br />
  27. 27. 26<br />Glycolysis: Oxidation of Glucose<br />Glycolysis generates <br /> 2 ATP molecules and 2 NADH + 2 H+<br /> Two ATP used in adding phosphate groups to glucose and fructose-6-phosphate (- 2 ATP)<br /> Four ATP generated in direct transfer to ADP by two 3-C molecules (+ 4 ATP)<br /> Glucose + 2 ADP + 2 Pi + 2 NAD+<br /> 2pyruvate + 2 ATP + 2 NADH + 2 H+<br />
  28. 28. 27<br />Pathways for Pyruvate<br />Aerobic conditions<br />O<br />||<br /> CH3–C –COO- + NAD+ + CoA<br />pyruvate<br /> O<br />||<br /> CH3–C –CoA + CO2 + NADH + H+<br />acetyl CoA<br />
  29. 29. 28<br />Pathways for Pyruvate<br />Anaerobic conditions(No O2 available)<br /> Reduce to lactate to replenish NAD+ for glycolysis<br />O OH <br />|| |<br />CH3–C –COO- + NADH + H+ CH3–CH –COO- + NAD+<br />pyruvate lactate<br /> enzyme: lactate dehydrogenase<br />
  30. 30. Glycolysis<br />
  31. 31. Alternative to Glycolysis<br />Pentose phosphate pathway<br />Uses pentoses and NADPH<br />Operates with glycolisis<br />Entner-Doudoroff pathway<br />Produces NADPH and ATP<br /> Does not involve glycolisis<br /> Pseudomonas, Rhizobium, Agrobacterium<br />
  32. 32. Intermediate step<br />Pyruvic acid (from glycolysis) is oxidized and decarboxylated<br />
  33. 33. The Krebs Cycle/ The Citric acid cycle (TCA cycle)<br />Oxidation of acetyl Co-A produces NADH and FADH2 (mitochondrion)<br />
  34. 34. The Electron Transport Chain<br />An electron transport chain (ETC) couples electron transfer between an electron donor (such as NADH) and an electron acceptor (such as O2) to the transfer of H+ ions (protons) across a membrane.<br />A series of oxidation-reduction reactions, the electron transport chain (ETC) performs 2 basic functions:<br />Accepting electrons from an electron donor and transferring them to an electron acceptor<br />Conserving for ATP synthesis some of the energy released during the electron transfer <br />A series of carrier molecules that are, in turn oxidized and reduced as electrons are passed down the chain<br />Energy released can be used to produce ATP by chemiosmosis<br />
  35. 35. The Electron Transport Chain<br />
  36. 36. The Electron Transport Chain<br />
  37. 37. Chemiosmosis<br />Electrons from the hydrogen atoms removed from the reactions of the Krebs cycle are transferred through the electron transport system<br />Electron transport creates the H potential across the membrane<br />Combination of hydrogen/electron carriers<br />
  38. 38. Chemiosmosis<br />
  39. 39. Chemiosmosis<br />
  40. 40. Questions?<br />
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