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Microbial Metabolism

Microbial Metabolism. Microbial Metabolism. The sum of all chemical reactions within a living organism Catabolism Anabolism. Catabolism. Destructive metabolism ; the breaking down in living organisms of more complex substances into simpler ones, with the release of energy

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Microbial Metabolism

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  1. Microbial Metabolism

  2. Microbial Metabolism • The sum of all chemical reactions within a living organism • Catabolism • Anabolism

  3. Catabolism Destructive metabolism; the breaking down in living organisms of more complex substances into simpler ones, with the release of energy (opposed to anabolism)

  4. CO2 + H2O + Energy Catabolism • Complex substances into simple ones, releases energy Glucose

  5. Catabolism Peptide Single amino acids Protein Energy

  6. Anabolism Constructive metabolism; the synthesis in living organisms of more complex substances from simpler ones, spending energy (opposed to catabolism )

  7. Amino acids + Energy Proteins Anabolism • Simple substances into complex ones, spend energy

  8. Anabolism Peptide Enzyme Energy Single amino acids Protein

  9. Enzymes • Speed up chemical reactions • Increase frequency of collision • Orient molecules • Lower activation energy • Low temperatures

  10. Enzymes (cont.) • Very efficient • Reactions occur 10 billion times faster than without enzyme • Enzyme does not change during reaction

  11. Substrate • Substance that the enzyme acts on (i.e.. Sucrose) sucrose + sucrase=glucose & fructose substrate+enzyme=product(s)

  12. Enzyme structure • three-dimensional shape (thousands of shapes) • lock and key complementary

  13. Enzyme structure Substrate Product Processing Enzyme Active site

  14. Turnover number • Maximum number of substrate molecules that one enzyme can process per second • 1 to 10,000, but may be as high as 500,000

  15. Enzyme cellular control • Repression • Induction

  16. Repression • Mechanism that inhibits the synthesis of an enzyme when the specific-end product is present in abundance, or the substrateis absent

  17. Induction • Mechanism that promotes the synthesis of an enzyme when the specific-end product is present in low concentration, or absent, and the substrateis present

  18. Repression/induction Lactose present B-galactosidase Glucose and galactose (end products) high concentration

  19. End-product and enzyme b-galactosidase (enzyme) Glucose and galactose (end products) Concentration Time

  20. Substrate and enzyme B-galactosidase Lactose (substrate) Concentration Time

  21. Substrate and enzyme B-galactosidase Lactose (substrate) Concentration Time

  22. Cofactors • Metal ions (Fe, Cu, Mg, Zn, Ca and Co) • Bridge between substrate and enzyme • Coenzymes • Derived from vitamins (B-vitamins) • Electron carriers (NAD+ & NADP+)

  23. Factors Influencing Enzymatic Activity • Temperature • pH • Inhibitors • Cyanide, arsenic, mercury

  24. Energy Production • Adenosine triphosphate (ATP) • Cell’s energy carrier • Mitochondria (eucaryotes) • Plasma membrane (bacteria)

  25. Respiration in eucaryotes Mitochondria Cell membrane Respiration in procaryotes (bacteria)

  26. Oxidation-Reduction (Redox reactions) • Highly reduced compounds (many Hydrogens) are high in energy (glucose) • Highly oxidized compounds are low in energy (CO2)

  27. Oxidation-Reduction (Redox reactions) (cont.) • Glucose (C6H12O6), reduced, high energy • CO2, oxidized, low energy

  28. Glucose • Respiration (O2 or inorganic substances as electron acceptors) • Fermentation (organic substances as electron acceptors)

  29. Glycolysis • First step in carbohydrate catabolism in both, respiration and fermentation • Does not require oxygen • 10 different reactions (enzymes)

  30. Glycolysis Glucose -C-C-C-C-C-C - Oxidation Pyruvic acid -C-C-C- -C-C-C -

  31. Glycolysis (cont.) • ATPs’ produced 4 • ATPs’ consumed 2 2

  32. Pyruvic acid C-C-C (2) Oxidation Krebs cycle 6CO2 + 6H2O + 38 ATP (pro) 36 ATP (eu) Aerobic Respiration • O2required

  33. Anaerobic respiration • Electron acceptor is an inorganic substance other than O2 (number of ATPs varies) NO3--->NO2 SO4---> H2S CO3--->CH4

  34. Fermentation • e- acceptor is an organic substance (pyruvate) • Products • Energy • Lactic acid • Alcohol

  35. Fermentation Glucose 2 Lactic acid 2 ATP

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