Microbiology Ch 5

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Author:
cswett
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63631
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Microbiology Ch 5
Updated:
2011-02-02 20:58:22
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Microbiology Metabolism
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Exam review notes for Ch 5 Metabolism
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  1. Metabolism
    anabolic
    catabolic
    Metabolism - sum of all chemical reactions in an organism

    Anabolic - requires energy - building - endergonic - dehydration synthesis

    Catabolic - releases energy - breaking down - exergonic - hydrolysis
  2. Enzymes vs. normal chemical reaction
    Enzymes are biological catalysts - they speed up reactions without increasing the temp or concentration of reactants (lover activation energy)

    • normal chemical reactions : reactants → products
    • you can increase rate of reaction by increasing temp or concentration of reactants (sometime impractical or impossible)
  3. Parts of an Enzyme
    Apoprotein - protein part

    cofactor - non-protein part

    coenzyme - if cofactor is organic)

    holoenzyme -whole enzyme

    • apoprotein + cofactor (or coenzyme) = holoenzyme
    • substrate - being acted upon - changed - fits in active site

    active site - where substrate binds

    allosteric site - where noncompeditive inhibitor binds
  4. How does an enzyme lower activation energy?
    The enzyme/ substrate complex orients the substrate to increase the probability of the reaction occuring ( allows most effective collisions to occur)
  5. How does an enzyme work?
    substrate + enzyme → enzyme-substrate complex → products released + enzyme unchanged
  6. turnover number of an enzyme
    number of products being produced per second
  7. 3 most important coenzymes (organic cofactor)
    • NAD+ nicotinamide adenine dinucleotide
    • NADP+ nicotinamide adenine dinucleotide phosphate
    • CoA - coenzyme A
  8. denaturation
    enzyme looses its tertiary structure due to unfavorable temp or pH (hydrogen and other non-covalent bonds are broken)
  9. Factors that affect enzyme activity
    1. Temperature - best at 35-40 OC - too high = denaturation

    2. pH - large changes cause denaturation

    3. concentration of substrate - ↑ substrate = ↑ rate of reaction UNTIL saturation - after saturation is reached more substrate w WILL NOT affect rate of reaction

    • 4. inhibitors
    • a. compeditive - fill active site
    • b. non-compeditive - fill allosteric stive
    • c. feedback inhibition - high concentation of products feeds back to enzyne and fills allosteric site to stop reaction
  10. Oxidized
    Reduced
    redox reaction
    purpose
    Oxidize = remove e- = remove H and add O

    reduced = gain e- = add H to it

    redox reaction - oxidation-reduction reactions are always couples - when one substance is oxydized another is reduced so called a redox reaction

    the purpose of redox reactions is to extract energy from nutrients (glucose) and couple it to ATP production.
  11. Phosphorylation
    Phosphorylation - adding a P (phosphate) to a chemical compound

    ADP + P + Energy → ATP

    • 1. Substrate level phosphorylation - direct transfer of P
    • 2. Oxidative phosphorylation - use of electron carriers *the transport of e- from one carrier to another releases energy→ATP made (electron transport chain)

    • 3. photosynthetic phosphorylation - in photosynthetic cells - uses electron carriers
    • light + ADP + P → ATP

  12. what macromolecules are used to make ATP?
    Most organisms use carbs as primary energy source but all (carbs, lipids, proteins, nucleic acids) can be used to produce ATP.
  13. Carbohydrate catabolism (glucose) path
    • Aerobic path
    • 1. glycolysis
    • 2. krebs cycle
    • 3. oxidative phosphorylation (electron transport chain)

    • Anerobic path
    • 1. Glycolysis
    • 2. fermentation → ethanol or lactic acid
  14. Glycolysis
    the oxidation of glucose to pyruvic acid, is usually the first stage in carbohydrate catabolism

    glycolysis means splitting of sugar

    also called the Embden-Meyerhof pathway

    glucose + ATP → 2 pyruvic acid (3 carbon sugar) + 2 net ATP
  15. Krebs cycle
    • purpose is to make NADH
    • also called the citric acid cycle
    • pyruvic acid must be decorboxylation → CO2 - removal of CO2 → acetyl CoA

    acetyl CoA → redox reactions to produce NADH
  16. Electron transport chain
    uses electron carriers - series of redox reactions

    as e- pass through chain, energy is released and coupled to ATP production called chemiosmosis

    • 3 electron carriers:
    • 1. flavoproteins
    • 2. cytochromes
    • 3. ubiquinones - coenzyme Q
  17. proteins can be used to make what macromolecules?
    Protein has C,H,O,N so can make carbohydrates, lipids, and protein + P = nucleic acid
  18. Formula for Aerobic Respiration
    C6H12O6 + 6 O2 → 6 CO2 + 6 H2O

    nets 36 ATP (eukaryotes) and 38 (prokaryotes)
  19. formula for Photosynthesis
    light + 6 CO2 + 6 H2O → C6H12O6 + 6 O2
  20. Photosynthesis
    • purpose if to make glucose + oxygen
    • -it "fixes" the CO2

    • light reaction = photo → ATP + NADPH + O2
    • dark reaction = synthesis → glucose

    energy that is created in the light reaction is used to make glucose in the dark reaction

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