Notes: Fermentation

 by facultative and obligate anaerobes and aerobes

NAD is the final electron acceptor (oxidizing agent) and is recycled after donating an electron to pyruvate.  Net ATP production is 2, as opposed to 36 via respiration.

In bacteria and muscle cells:
C6H12O6CH3-COH-COO- (pyruvate)CH3-CHOH-COO- (lactate)

In plant cells:
C6H12O6CH3-COH-COO- (pyruvate)CH3-CH2OH (ethanol)

Substrate-level phosphorylation makes the ATP.

Lactic acid is used to produce cottage cheese and yogurt.

Obligate aerobes

 Obligate Anaerobes Facultative Anaerobes
must be in an oxygen rich environment. cannot survive in an oxygen rich environment. survive in both environments; yeast is an example, also muscle cells (lactate production).

Muscle cell lactic acid fermentation

When sugar catabolism is great than supply of oxygen from the blood, muscles switch to fermentation from cellular respiration.  In this case lactate may cause muscle fatigue and pain but it is carried away (usually) to the liver where it is turned into pyruvate.

 

Next:  "Photosynthesis:  Pigments."