Two Fates of Pyruvate

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Two Fates of Pyruvate
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Importance of Fermentation

• Fermentation
• -Allows for the regeneration of NAD
• -Produces Lactic acid or Alcohol (ethanol)
• -Important in industry for producing
• Alcoholic beverages
• Bread
• Yogurt
• -Bacteria and Unicelluar Fungi (Yeast)

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Facultative Anaerobes (pg. 176, 539)

• Most are Unicelluar, Eukaryotic cells
• Yeast-have mitochodria
• Some are Prokaryotic - use the cell membrane to
  do oxidative phosphorylation
• Switch Aerobic to Anaerobic depending on O2
  levels
• Undergoes alcoholic fermentation when O2 is not
  available.
• Obligate anerobes die in the presence of O2

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Two Processes of Fermentation
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Lactic Acid Fermentation

• Observed in Certain Fungi Bacteria
• Pyruvate (receives a hydrogen) ? Lactate
• Used to produce yogurt (Lactobacillus)
  sauerkraut
• Produced during strenuous exercise in muscle
  cells (Cells briefly switch temporarily)
• Causes fatigue and cramps
• Lactate produced is transported to the liver
  where it is used to regenerate more glucose.

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Lactic acid Fermentation
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Alcoholic Fermentation

• Pyruvate is decarboxilized ? Acetaldehyde
• Acetaldehyde becomes reduced (gains a hydrogen
  from NADH to form ethyl alcohol
• Used for producing alcoholic beverages (beer
  wine)
• Yeast cells are use for making bread
• CO2 is released causing the bread to rise.

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Alcoholic Fermentation
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ATP Production in the Steps of Aerobic Respiration
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Transforming Pyruvate into Acetyl CoA While it
Enters into the Mitochondria
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Pyruvate?Acetyl CoA ? Kreb Cycle(3 carbons)
(2 Carbons)

• Beginning of Kreb Cycle
• Production of
• NADH FADH2
• ATP Formed

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Specific Details of the Kreb Cycle
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Two Examples of the Kreb Cycle (Pg 161-162)
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Krebs Cycle

• for facultative anearobesIf molecular oxygen
  is present.
• 1. Pyruvate ? Acetyl CoA
• 2. Oxaloacetate Acetyl CoA produces
• Citric Acid
• 3. Dehydrogenase is used
• 4. Kinase is used to make GTP (ATP)
• 5. Generates 4 molecules of CO2
• 6. Produces more NADH FADH2