Free Anaerobic Respiration OCR A Level Biology revision notes – covering specification point 5.2.2 (ii).
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Anaerobic respiration occurs when oxygen is not available as the final electron acceptor in the electron transport chain.
Anaerobic respiration allows glycolysis to continue producing ATP in the absence of oxygen by regenerating NAD from reduced NAD.
Anaerobic respiration’s (indirect) yield of ATP is only 2.
The Importance of Anaerobic Respiration
Anaerobic respiration is important to organisms because it enhances their survival:
- Survive short periods without oxygen (e.g. diving mammals, waterlogged plant roots).
- Produce additional ATP during intense activity when aerobic respiration cannot supply enough.
- Provide faster ATP production through glycolysis than aerobic respiration.
Anaerobic Respiration in Mammals
In mammals, anaerobic respiration (also known as lactate fermentation) occurs in muscle tissue, providing additional ATP during strenuous activity.
Lactate fermentation converts pyruvate into lactate.
The diagram below outlines the process of lactate fermentation:
Anaerobic Respiration in Yeast
In yeast, anaerobic respiration (also known as ethanol fermentation) occurs when oxygen is unavailable, allowing ATP production to continue.
Ethanol fermentation converts pyruvate into ethanol and carbon dioxide.
The diagram below outlines the process of ethanol fermentation:
