1. Fermentation
Sections

2. 6.13 Fermentation
Fermentation is a way of harvesting chemical energy that does not require oxygen. Fermentation
takes advantage of glycolysis,
produces two ATP molecules per glucose, and
reduces NAD+ to NADH.
Fermentation must provide an anaerobic path for recycling NADH back to NAD+.
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3. 6.13 Lactic acid Fermentation
Your muscle cells (when?) and certain bacteria can oxidize NADH through lactic acid fermentation, in which
NADH is oxidized to NAD+ and
pyruvate is reduced to lactate.
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4. Glucose 2 ADP 2 NAD 2 P Glycolysis 2 ATP 2 NADH 2 Pyruvate 2 NADH
Figure 6.13A
Glucose
2 ADP
2 NAD
2 P
Glycolysis
2 ATP
2 NADH
2 Pyruvate
2 NADH
Figure 6.13A Lactic acid fermentation: NAD+ is regenerated as pyruvate is reduced to lactate.
2 NAD
2 Lactate 4

5. 6.13 Lactic Acid Fermentation
Lactate is carried by the blood to the liver, where it is converted back to pyruvate and oxidized in the mitochondria of liver cells.
Bacteria: What foods are produced by lactic acid fermentation?
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6. In this process yeasts (single-celled fungi)
6.13 Fermentation
Alcohol Fermentation
In this process yeasts (single-celled fungi)
oxidize NADH back to NAD+ and
convert pyruvate to CO2 and ethanol.
What foods are produced by alcohol fermentation?
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7. Glucose 2 ADP 2 NAD Glycolysis 2 P 2 ATP 2 NADH 2 Pyruvate 2 NADH
Figure 6.13B
Glucose
2 ADP
2 NAD
2 P
Glycolysis
2 ATP
2 NADH
2 Pyruvate
Figure 6.13B Alchohol fermentation: NAD is regenerated as pyruvate is broken down to CO2 and ethanol.
2 NADH
2 CO2
2 NAD
2 Ethanol 7

8. Facultative anaerobes
6.13 Fermentation
Obligate anaerobes
Facultative anaerobes
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9. The ancient history of glycolysis is supported by its
6.14 EVOLUTION CONNECTION: Glycolysis evolved early in the history of life on Earth
The ancient history of glycolysis is supported by its
occurrence in all the domains of life and
Uses pathways that do not involve any membrane-bounded organelles.
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10. 6.15 Cells use many kinds of organic molecules as fuel for cellular respiration
Although glucose is considered to be the primary source of sugar for respiration and fermentation, ATP is generated using
carbohydrates,
fats, and
proteins.
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11. Pyruvate Oxidation Acetyl CoA Oxidative Phosphorylation
Figure 6.15
Food, such as peanuts
Carbohydrates
Fats
Proteins
Sugars
Glycerol
Fatty acids
Amino acids
Amino groups
Figure 6.15 Pathways that break down various food molecules
Citric Acid Cycle
Pyruvate Oxidation Acetyl CoA
Oxidative Phosphorylation
Glucose
G3P
Pyruvate
Glycolysis
ATP 11