SUGAR is converted to alcohol.Alcohol fermentation by yeast produces ethanol found in alcoholic BEVERAGES such as beer and wine.However, alcohol is poisonous to yeasts in large amounts (as it is to humans), which sets an upper LIMIT on the percentage of alcohol in these beverages.The yeast tolerance ranges from approximately 5% to 21% depending on the yeast strain and the environmental conditions.Anaerobic CELLULAR respiration is similar to aerobic cellular respiration in that electron derived from a fuel molecule travel through an electron transport chain, driving ATP SYNTHESIS.