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Bacterial Metabolism

Bacterial Metabolism. Chapter 6. Objectives for today. This is a big, complicated topic What process produces ATP? What is the purpose of the Coenzymes? Where are these produced?. Some Definitions. Electron Carriers:

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Bacterial Metabolism

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  1. Bacterial Metabolism Chapter 6

  2. Objectives for today • This is a big, complicated topic • What process produces ATP? • What is the purpose of the Coenzymes? • Where are these produced?

  3. Some Definitions • Electron Carriers: • Compounds that can accept electrons (and protons) to drive the production of ATP • Compounds can easily transfer their electrons to other molecules • NAD+, NADP+, FAD • Reduced form: NADH, NADPH, FADH2

  4. More Definitions • Redox Reactions (Reduction/Oxidation) • Oxidation: Loss of electrons • Reduction: Gain of electrons • ATP Adenosine Triphosphate

  5. Metabolism • The sum total of ALL chemical reactions within a cell • Catabolic • Creates ATP • Anabolic • Uses ATP • Creates other biomolecules

  6. Energy is the capacity to do work • Potential energy: stored energy • Kinetic energy: energy of motion

  7. Organisms obtain energy from different sources • Photosynthetic organisms obtain energy from… • Chemoorganotrophs obtain energy from…..

  8. Chemoorganotrophs depend on photosynthetic organisms

  9. What promotes chemical reactions in biological systems? ENZYMES

  10. Enzymes bind substrate and generate a product, enzyme is unchanged

  11. Some enzymes require a cofactor to bind substrate

  12. How does this relate to metabolism?

  13. Coenzymes carry electrons These are a class of enzymes

  14. Factors that influence an enzyme: Temperature • What happens as temperature increases? • What is the optimum temperature? • What would happen if you put a mesophilic organism in a thermophilic environment?

  15. Factors that influence an enzyme: pH • What pH do most enzymes function optimally?

  16. Enzyme inhibitors • Inhibit the binding of the substrate to the active site • Competitive inhibition • Non-Competitive Inhibition

  17. Competitive Inhibition Sulfa drugs can block PABA binding interfering with folic acid synthesis

  18. Non-competitive Inhibition

  19. Oxidation/reduction reactions These are especially important for coenzymes

  20. Biological Oxidation

  21. ATP is made in catabolic reactions and used in anabolic reactions

  22. Ways cells make ATP • Substrate level phosphorylation • Uses energy from breaking down chemicals • Energy used to add phosphate groups • Oxidative phosphorylation • Uses energy from proton motive force • Uses gradient created in ETS • Photophosphorylation • Uses energy created from photons

  23. Types of Bacterial Metabolism • Fermentation • Respiration • Aerobic Respiration • Anaerobic Respiration • Photosynthesis

  24. Keep in mind…glucose becomes many different things

  25. Fermentation • The incomplete breakdown of glucose with an organic compound serving as the final electron acceptor • Only pathway operating is glycolysis

  26. The big picture: This process results in the conversion of 1 glucose molecule into 2 pyruvate molecules that will be used in the TCA cycle, fermentation, etc

  27. Fermentation Ethanol Lactic Acid

  28. Lactic Acid Bacteria

  29. Saccharomyces produces ethanol

  30. Fermentation products can vary

  31. Aerobic Respiration • The COMPLETE breakdown of glucose to CO2 and H2O with an inorganic compound serving as the final electron acceptor

  32. Remember the pathways in aerobic respiration are… • Glycolysis • Some use Pentose Phosphate Pathway instead • TCA cycle • Electron transport chain

  33. Glycolysis: Creates Pyruvate Uses 2 ATP molecules and you gain 4 (net 2)

  34. This process generates ATP, FADH2 and NADH with CO2 being the bi-product http://www.youtube.com/watch?v=WXHpTHb1MQM

  35. What is made as a result of the TCA cycle? • ATP • Reducing power • NADH, NADPH, FADH2 • Provides Hydrogen gradient in ETC • Precursor metabolites made from alpha-ketoglutarate and oxaloacetate

  36. Electron Transport Chain • Found in the cytoplasmic membrane • Contains electron carriers • Flavoproteins (FAD) • Synthesized from vitamins • Iron-sulfur proteins • Quinones • Lipid soluble electron carriers • Cytochromes • Iron centered molecules

  37. Model for energy release in ETC

  38. ETC in eukaryotes http://www.youtube.com/watch?v=xbJ0nbzt5Kw http://www.youtube.com/watch?v=3y1dO4nNaKY

  39. ETC in prokaryotes

  40. ATP yield from aerobic respiration

  41. Comparison of three types of metabolism

  42. Remember we are focusing on catabolic reactions • Generate ATP for later use by cell • Generate precursors for other pathways • Need to re-oxidize coenzymes for continual use

  43. Precursor metabolites

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