Page 87 - Medicinal Plants_PharmD general

Anaerobic Respiration (NADH  NAD)

Normally, higher plants are not able to live long in the absence of
oxygen. Under this condition the food is not sufficiently oxidized to yield
enough energy for life processes, and certain products formed may be
poisonous. In contrast some fruits, notably apples, may be held for long
periods in an atmosphere containing very small amounts of oxygen and
continue to give off carbon dioxides. Yeast may live actively in an
atmosphere with very small amounts of oxygen and produce relatively
large amounts of carbon dioxide and alcohol, but yeast have a limited
tolerance for alcohol. When the alcohol concentration in the medium in
which they are living reaches about 12% the yeast cells are killed. This is
why wines and other naturally fermented alcoholic beverages do not have
an alcohol content above about 12%.

There are two types of anaerobic respiration or fermentation:
1. lactic acid fermentation.
2. Alcoholic fermentation.

 Regenerate the electron carrier NAD+ from the NADH produced in
glycolysis by donating its electrons to an acceptor molecule in a reaction
that doesn’t make ATP.

 This allows glycolysis to keep running by ensuring a steady supply of
NAD+.

 During the processes of fermentation, no additional ATP is synthesized.

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