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2009-10-29 22:45:12
MJC Micro 101 Microbial Metabolism

Lecture Test 2 Microbial Metabolism Lecture
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  1. Do microbes create energy from nutrients?
    • No energy is never created nor destroyed, only moved around.
    • They extract energy that is already present in the bonds of the nutrients.
  2. What is a Oxidation-reduction (redox) reaction?
    It is a reaction that salvages electrons (and the energy associated with them) released from the breaking of nutrient bonds.
  3. What is ATP?
    How energy is banked.
  4. What happens in a Oxidation reaction?
    Oxidation is the removal of electrons from a molecule, and is always coupled with a Reduction reaction.
  5. What happens in a reduction reaction?
    Reduction is the gaining of electrons, and are always coupled with Oxidation.
  6. What is a dehydration reaction?
    • This is the removal of hydrogen atoms.
    • Biological oxidation reactions are often dehydration reactions.
  7. Catabolic reaction
    NAD+ + 2H++2e- = NADH+H+

    This is energy extracted in the form of electrons
  8. What is the high energy of the cell?
    • ATP
    • ATP has "high energy" or unstable bonds which allows the energy to be released quickly and easily
  9. What are the mechanisms of ATP generation?
    • Substrate-level phosphorylation
    • Oxidative phosphorylation
    • Photophosphorylation
  10. What is substrate-level phosphorylation
    Generation of ATP when a high energy phosphate is transferred directly to ADP from a phosphorylated substrate.
  11. What is Oxidative phosphorylation
    Electrons are transferred from organic compunds through a series of electron carriers to O2 or other oxidized inorganic or organic molecules.
  12. What is photophosphorylation
    This occurs in photosynthetic cells, the light causes chlorophyll to give up electrons
  13. How do microbes generate energy?
    • By the oxidation of..
    • Carbohydrates
    • Proteins
    • Fats
    • Vitamins
    • Minerals
    • Water
  14. In what ways to microbes catabolise carbohydrates?
    • Cellular respiration
    • Fermentation

    Both start with Glycolysis
  15. What are the components of cellular respiration?
    • Glycolysis
    • Intermediate step
    • TCA cycle (Kreb's cycle)
    • Electron Transport Chain
  16. What is Glycolysis?
    Glucose is oxidized to pyruvic acid with ATP and NADH produced
  17. What is the Intermediate step?
    Pyruvic acid is converted to acetyle-CoA with NADH produced
  18. What is the TCA/Kreb's cycle?
    Acetyl CoA is oxidized to CO2 with ATP, NADH and HADH2 produced
  19. What is the electron transport chain
    NADH and HADH2 are oxidized through a series of redox reactions and a considerable amount of ATP is produced
  20. How many steps are in glycolysis?
    10 steps
  21. Phosphogluconate pathway
    • Used simultaneously with glycolysis (several intermediates can reenter glycolysis)
    • Breakdown of 5-carbon sugars(pentoses) as well as glucose
    • Produces important intermediates in the synthesis of, Cucleic acids, glucose from Co2 and certian amino acids
    • Produces NADPH for anabolic reaction
    • Yealds only 1 atp per glucose
  22. Entner-Doudoroff pathway
    • Bacteria can metabolize glucose without glycolysis or pentose phosphate pathway.
    • Produces 2 NADPH and 1 ATP/glucose
    • Used by obligate aerobes such as Pseudomonas Spp.
  23. What happens after glycolysis
    • After glucose is broken down to pyruvic acid, it can be channeled into either Fermentaion or
    • Cellular respiration.
    • Aerobic respiration or anaerobic respiration
  24. What is arobic respiration
    • Tricarboxylic acid (TCA) cycle
    • Kreb's cycle or citric acid cycle
    • A large amount of potential energy stored in acetyl CoA is released by a series of redox reactions that transfer electrons to the electron carrier coenzymes (NAD+ and FAD)
  25. Acetyl CoA
    • Used in the intermediate step
    • Pyruvic acid is converted to a 2-carbon compound (decarboxylation)
    • The 2 carbon acetle group then combines with Coenzyme A through a high energy bond
    • NAD+ is reduced to NADH
  26. Summary of Glycolysis
    • Glucose is split and oxidized through a ten step pathway to two molecules of pyruvic acid
    • Net gain of 2 ATP molecules, 4 from energy phase(by substrate level phosphorylation) mins 2 from preparatory phase
    • 2 NADH molecules produced (will be used to make more ATP)
    • Pyruvic acid can now undergo either Fermentation or respiration