Anaerobic Respiration and Fermentation

• Anaerobic Respiration

  • It does not rely on the presence of oxygen to produce ATP.
  • Glucose still undergoes glycolysis, citric acid cycle, and oxidative phosphorylation.
• Anaerobic Respiration

  • The final electron acceptors are inorganic electron acceptors other than oxygen to generate ATP. These inorganic electron acceptors may include nitrates, sulfates, and carbonates.
  • It produces less ATP compared to aerobic respiration.
• Fermentation

  • It happens in the absence of oxygen.
  • It allows cells to produce ATP.
  • Sugars such as glucose are partially degraded without oxygen. Among the three stages of cellular respiration, only glycolysis can produce ATP with or without oxygen
• Alcohol Fermentation

  • It occurs in bacteria and fungi such as yeast.
  • Pyruvate produced from glycolysis is converted into ethanol.
• Lactic Acid Fermentation

  • It occurs in some bacteria, plants, and most animals.
  • Pyruvate is directly reduced by NADH to form lactate as a waste product.
• Applications of Fermentation

  • The process of alcohol fermentation is commonly used to produce beer, wine, and other alcoholic beverages.
  • Yogurt, and bread are products of fermentation.
• Yeast


  a fungus that undergoes alcohol fermentation, is used to raise dough in making bread due to carbon dioxide
• Dairy products

  yogurt and cheese are produced by lactic acid fermentation.
• Anaerobic respiration

  • does not rely on the presence of oxygen to produce ATP.
  • Compared to aerobic respiration, the final electron acceptors in anaerobic respiration are inorganic electron acceptors other than oxygen to generate ATP.
  • These inorganic electron acceptors may include nitrates, sulfates, and carbonates.
  • Anaerobic respiration produces less ATP compared to aerobic respiration.
• Fermentation

  • It starts with the consumption of pyruvate, which is the end-product for glycolysis.
  • NADH, also another end-product during glycolysis, is recycled in fermentation.
  • Fermentation is another example of a catabolic process.
• Pyruvate conversion to ethanol formation

  1. Pyruvate is converted to acetaldehyde. CO2 is produced.
  2. Acetaldehyde is reduced by NADH to NAD+ to form ethanol.
  3. The end products are two ethanol and two carbon dioxide molecules for every glucose. Two ATP molecules are also produced in the reaction.
• Alcohol Fermentation

  
• Types of Fermentation

  • Alcohol Fermentation
  • Lactic Acid Fermentation
• Lactic Acid Fermentation

  • Lactic acid fermentation is common in some bacteria, plants and most animals. In lactic acid fermentation, pyruvate is directly reduced by NADH to form lactate as a waste product.
  • The end products are two lactate molecules for every glucose.
  • Two ATPs are also produced in the reaction.
  • No carbon dioxide is produced in the reaction. When there is a buildup of lactate in animals, fatigue and cramps occur.