Similarities and Differences between Fermentation and Cellular Respiration
Tracy Stroud (mod. by Dr. Orr)
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Similarities
Both begin with glycolysis
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Both use glycolysis to oxidize glucose to pyruvate
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Both generate ATP by substrate-level phosphorylation
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In both, NAD+ is the oxidizing agent
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In both, NAD+ accepts electrons from food during
glycolysis
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Both harvest chemical energy from food. Both require ATP
to proceed. Both have end products produced as a result.
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Both begin in the cytoplasm
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Differences
Total ATP generated by fermentation (2 ATP) <
aerobic (cellular) respiration (34 ATP)
Fermentation=anaerobic, Cellular
Respiration=aerobic
KEY difference is the contrasting mechanism for
oxidizing NADH back to NAD+ (which is required
to sustain glycolysis)
In fermentation, the final electron acceptor is an
organic molecule: pyruvate (producing lactate)
(Lactic Acid Fermentation) or acetylaldehyde
(producing ethanol) (alcohol fermentation). In
respiration, the final electron acceptor from NADH is
oxygen (producing water)
Respiration regeneration of NAD+ (required for
glycolysis) results in extra ATP pay out, fermentation
regeneration of NAD+ yields no extra ATP
Respiration, even bigger ATP payoff comes from
oxidation of pyruvate in the citric acid cycle.
Fermentation, pyruvate cannot be utilized to generate
any more ATP
Cell Respiration continues in the mitochondria,
fermentation does not utilize the mitochondria
Oxidative phosphorylation *only* occurs in cell
respiration (not fermentation!)