FATES OF PYRUVATE

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• FATES OF PYRUVATE
• Depends upon presence or absence of O2
• Anaerobic conditions
• 1)alcohol fermentation pyruvate converted to
  ethyl alcohol
• 2)lactic acid fermentation - pyruvate converted
  to lactic acid (cheese, yogurt)
• - Aerobic conditions
• Pyruvate enter the mitochondria where it is
  completely oxidized
• Pyruvate -gt enzyme -gt acetyl group CO2 NADH
• (3C) (pyruvate (2C)
• dehydrogenase)
• From 2 pyruvates
• 2 acetyl fragments
• 2 CO2 exhaled
• 2 NADH
• Acetyl fragment joins Coenzyme A (CoA) and enters
  Krebs Cycle in mitochondrial matrix

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We end up with what we start off with 1 turn of
the cycle from glucose oxidation
reactions decarboxylations ATP
reduced NADH reduced FADH2
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Energy Yield So Far

• Glycolysis
• 2 ATP, 2 NADH
• Pyruvate Oxidation
• 2 NADH, 2 CO2
• Krebs Cycle
• 2 ATP
• 6 NADH
• 2 FADH2
• 4 CO2

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Electron Transport Complexes

• Only 3 sites that can pump protons II cant
• Complex I NADH Dehydrogenase
• Takes H off NADH conducts e- from NADH to
  ubiquinone
• Complex II succinate dehydrogenase conducts
  e- from FADH2 to ubiquinone
• Complex III cytochrome BC1 conducts e- from
  ubiquinone cytochrome C
• Complex IV cytochrome oxidase conducts e-
  from cytochrome O2, THE FINAL ELECTRON ACCEPTOR

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Adding up the ATP

• Glycolysis 2 ATP
• Krebs 2 ATP
• 10 NADH x 3 ATP/NADH 30 ATP
• 2 FADH2 x 2 ATP/FADH2 4 ATP

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Control of ATP Synthesis

• Controlled by energy needs of the cell
• Enzymes in Glycolysis and Krebs control this