Answer
anaerobic fermentation
Work Step by Step
When oxygen is too limited to meet a cell's ATP demand, a cell can employ a metabolic pathway called anaerobic fermentation to produce ATP.
Anaerobic comes from an- "without" and aero- "oxygen". Anaerobic fermentation does not produce any additional ATP than what was extracted from the pyruvic acid and produces toxic lactic acid. The purpose of anaerobic fermentation is as a temporary measure to produce just enough ATP so that glycolysis can start up again when oxygen becomes available.
