Micro Chapter 5: Microbial Nutrition and Metabolism

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Micro Chapter 5: Microbial Nutrition and Metabolism
2011-06-18 00:18:45

Exam 2
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  1. Metabolism
    the sum of all the chemical processes carried out by living organisms
  2. anabolism
    reactions that require energy to synthesize complex molecules from simpler ones

    needed for growth, reproduction, and repair of cellular structures
  3. catabolism
    reactions that release energy by breaking complex molecules into simpler ones that can then be reused as building blocks

    provides an organism with energy for its life processes, including movement, transport, and the synthesis of complex molecules (anabolism)
  4. electron transfer
    allows energy to be captured in high-energy bonds in ATP and similar molecules

    found in all catabolic reactions
  5. oxidation
    the loss or removal of electons
  6. reduction
    the gain of electrons
  7. autotrophy
  8. heterotrophy
  9. autotrophs
    use carbon dioxide to synthesize organic molecules

  10. photoautotrophs
    obtain energy from light
  11. chemoautotrophs
    obtain energy from oxidizing simple inorganic substances such as sulfides and nitrites
  12. heterotrophs
    get their carbon from ready-made organic molecules, which they obtain from other organisms, living or dead
  13. photoheterotrophs
    obtain chemical energy from light
  14. chemoheterotrophs
    obtain chemical energy from breaking down ready-made organic compounds
  15. glycolysis
    oxidation of glucose to pyruvic acid
  16. fermentation
    conversion of pyruvic acid to ethyl alcohol, lactic acid, or other organic compounds
  17. aerobic respiration
    oxidation of pyruvic acid to carbon dioxide and water
  18. glycolysis equation
    C6H12O6 + 6O2 -----> 6CO2 + 6H2O + energy
  19. photosynthesis equation
    6CO2 + 6H2O -------> C6H12O6 + 6O2
  20. FIGURE 5.2
  21. metabollic pathway
    a series of chemical reactions in which the product of one reaction serves as the substrate from the next
  22. Catabolic pathways
    capture energy in a form cells can use
  23. Anabolic pathways
    make the complex molecules that form the structure of cells, enzymes, and other molecules that control cells
  24. The links that couple catabolic catabolic and anabolic pathways
    ATP molecules
  25. enzymes
    act as catalysts in biochemical reactions
  26. activation energy
    energy required to start a reaction
  27. Why lower activation energy in cells?
    cells would raise the temperature enough to denature proteins and evaporate liquids
  28. active site
    binding site
  29. substrate
    the substance on which the enzyme acts

  30. The effect of enzymes on activation energy
  31. specificity
    catalyze only one type of reaction, and most act on only one particular substrate
  32. endoenzymes
    intracellular enzymes, act within the cell that produced them
  33. exoenzymes
    extracellular enzymes, are synthesized in a cell but cross the cell membrane to act in the periplasmic space or in the cell's immediate environment
  34. apoenzyme
    protein portion of an enzyme
  35. coenzyme
    a nonprotein organic molecule bound to or loosely associated with an enzyme
  36. many coenzymes are synthesized from __________.
  37. coenzyme A is made from _________.
    pantothenic acid
  38. NAD is made from ____________.
  39. cofactor
    usually an inorganic ion, such as magnesium, zinc, or manganese
  40. competitive inhibitor
    competes with the substrate from the active site
  41. noncompetitive inhibitors
    attach to the enzyme at an allosteric site,which is a site other than the active site
  42. feedback inhibition
    a kind of reversible non-competitive inhibition that regulates the rate of many metabolic pathways
  43. factors that affect the rate of enzyme reactions:
    • 1) Temperature
    • 2) pH
    • 3) concentrations of substrate, product, and enzyme
  44. enzyme activity
    the rate at which an enzyme catalyzes a reaction
  45. four important events of glycolysis:
    • 1) Substrate-level phosphorylation (the transfer of phosphte froups from ATPs to glucose)
    • 2)Breaking of a six-carbon molecule (glucose) into two three-carbon molecules
    • 3)The transfer of two electrons to the coenzyme NAD
    • 4)The capture of energy in ATP
  46. phosphorylation
    the addition of a phosphate group to a molecule, often from ATP
  47. end products of glycolysis
    two molecules of pyruvic acid and two molecules of reduced NAD (NADH)
  48. metabolic pathway of Bacillus subtilis and E. coli:
    pentose phosphate pathway
  49. fermentation
    pyruvic acid is subsequently metabolized in the absence of oxygen
  50. homolactic acid fermentation
    pyruvic acid is converted directly to lactic acid, using electrons from reduced NAD

    used in making cheeses
  51. alcoholic fermentation
    carbon dioxide is released from pyruvic acid to form the intermediate acetaldehyde, which is quickly reduced to ethyl alcohol by electrons from reduced NAD
  52. the Krebs cycle (citric acid cycle)
    metabolizes two-carbon units called acetyl groups to CO2 and H2O
  53. pyruvic acid must be converted to __________ to enter the Krebs cycle
    acetyl CoA
  54. Significate events of the Krebs cycle:
    • -the oxidation of carbon
    • -the transfer of electrons to coenzymes
    • -the substrate-level energy capture
  55. electron transport
    the process leading to the transfer from substrate to O2
  56. electron transport chain functions:
    • 1) accepting electrons from an electron donor and transferring them to an electron acceptor
    • 2) conserving for ATP synthesis some of the energy released during the electron transfer
  57. oxidative phosphorylation
    energy is captured in high-energy bonds as Pi combines with ADP to form ATP
  58. chemiosmosis
    ADP is converted to ATP by a large ATP-synthesizing complex called ATP synthase

    a major contribution to the understanding of how ATP is formed during the electron transport
  59. ATP produced in oxidative phosphorylation
    34 ATPs
  60. ___________ as much energy is captured in aerobic metabolism as in fermentation.
    19 times!
  61. light reactions
    • Light strikes the freen pigment chlorophyll a in thylakoids of chloroplasts. Electrons in the chlorophyll become excited (raised to a higher energy level).
    • Products= ATP and NADPH
  62. dark reactions (carbon fixation)
    occurs in the stroma of chloroplasts
  63. amphibolic pathways
    can yield enegy or building blocks for synthetic reactions
  64. porins
    form channels through the outer membrane
  65. bioluminescence
    the ability of an organism to emit light (appears to be a by-product of aerobic metabolism)