Anaerobic Respiration
Biology: IB Diploma Higher Level, topic 2.7.2
Anaerobic Respiration
The end product of glycolysis is pyruvate and this can then be used in aerobic or anaerobic respiration. There are two types of anaerobic respiration: ethanol fermentation and lactate fermentation.
Ethanol fermentation
- Ethanol fermentation is the conversion of pyruvate to ethanol under anaerobic conditions.
- This process only takes place in plants and yeast.
Pyruvate → ethanol
Pyruvate → ethanol
- Pyruvate is first converted to ethanal by the enzyme pyruvate decarboxylase.
- CO2 is produced as a by-product.
- Ethanal is then reduced to ethanol.
- This reaction is catalysed by ethanol dehydrogenase.
- NADH is oxidised to NAD.
Lactate fermentation
- Lactate fermentation is the conversion of pyruvate to lactate.
- This process takes place in animals and some bacteria. It is common in skeletal muscle when there is an insufficient oxygen supply, such as during exercise.
Pyruvate → lactate
Pyruvate → lactate
- Pyruvate is reduced to lactate.
- This reaction is catalysed by lactate dehydrogenase.
- NADH is oxidised to NAD.
Test yourself on Anaerobic Respiration
What are the two types of anaerobic respiration?
Which enzyme catalyses the conversion of pyruvate to ethanal?