Most organisms undergo cellular Most organisms undergo cellular respiration to produce energy. respiration to produce energy. However when there is an absence of However when there is an absence of oxygen, an organism will go through oxygen, an organism will go through a process called fermentation. a process called fermentation.

Fermentation does not create glucose, Fermentation does not create glucose, however it does allow glycolysis to however it does allow glycolysis to continue so that ATP is produced. continue so that ATP is produced. There are two types of fermentation: There are two types of fermentation: Lactic Acid Fermentation Lactic Acid Fermentation and and Alcohol Alcohol FermentationFermentation. .

Lactic Acid FermentationThis process occurs in your muscle cells. The build up of lactic acid is what causes muscles to “burn” during exercise.

What happens? The cells undergo glycolysis to break

down glucose into 2 pyruvates. In this process, 2 ATP and 2 NADHs are formed.

Two NADH molecules provide energy to convert pyruvate into lactic acid. As the NADH is used, it is converted back into NAD+.

Two molecules of NAD+ are recycled back to glycolysis, so that NADH can be reformed.

Alcoholic Fermentation

Occurs in yeast and some plants.

What happens? The cells undergo glycolysis to break down

glucose into 2 pyruvates. In this process, 2 ATP and 2 NADHs are formed.

Two NADH molecules provide energy to break down pyruvate into an alcohol and carbon dioxide. As the NADH is used, it is converted back into NAD+.

Two molecules of NAD+ are recycled back to glycolysis, so that NADH can be reformed.