bio chp 9

    • define: a metabolic pathway that regenerates NAD+ from stockpiles of NADH, allows glycolysis to continue producing ATP in absence of oxygen
    • process stops before pyruvate processing
    • in most organisms cellular respiration cannot occur without oxygen
  2. when does it occur?
    • when pyruvate or a molecule derived from pyruvate accepts e- from NADH
    • the transfer of e- oxidizes NADH to NAD+
  3. with NAD+
    glycolysis can continue to produce ATP via substrate-level phosphorylation
  4. fermentation will end with:
    • a net of 2 ATP
    • per glucose molecule:
    • fermentation --- 2 ATP
    • cellular respiration --- 29 ATP
  5. different fermentation pathways
    • lactic acid fermentation: occurs in most multi-cellular organisms
    • alcohol fermentation: ethanol & NAD+ are produced, occurs in yeast
  6. lactic acid fermentation
    • pyruvate produced by glycolysis accepts e- from NADH
    • lactate and NAD+ are produced
    • occurs in muscle cells
    • *no oxygen present
  7. alcohol fermentation
    • pyruvate is enzymatically converted to acetaldehyde & CO2
    • acetaldehyde accepts e- from NADH
    • ethanol & NAD+ are produced
  8. what happens during extreme exercise
    • no O2 present:
    • glucose --- pyruvate(oxidized) + NADH(reduced) ---lactate(reduced) + NAD+(oxidized)
    • NAD+ is reused to make more glucose to start the process all over
    • build up of lactic acid...side cramp! end with a lot of lactic acid in liver, its converted to glucose(in case lack of more O2)
Card Set
bio chp 9
november 21, 2010