In oxygen- starved muscle cells in anaerobic respiration lactic acid is formed while in anaerobic respiration by yeast cells it produces ethanol and carbon dioxide.
Explanation:
Respiration occurring in absence of oxygen in muscles leads to accumulation of lactic acid and very less amount of energy. This is fermentation process as the end product formed is lactic acid.
The process of fermentation takes place in yeast bacteria and oxygen starved cells of muscles.
The yeast can ferment simple sugars like glucose and fructose into ethyl alcohol and carbon dioxide.
In general human respiration is aerobic but during strenuous exercise, oxygen does not meet the demand of working out muscle, so they respire anaerobically and produce lactic acid and 2 ATP i.e very less compared to 38 molecules of ATP in aerobic respiration.
