Final answer:
Fermentation is the process where yeast and other single-celled organisms break down sugars into ethanol and carbon dioxide in the absence of oxygen. It is less energy-efficient than aerobic respiration but allows organisms to survive and produce energy without oxygen, playing a key role in making bread, wine, and beer.
Step-by-step explanation:
The process that occurs when yeast and other single-celled organisms break down sugars is called fermentation. In the absence of oxygen, organisms like yeast undergo alcoholic fermentation, a type of anaerobic respiration, where sugars such as glucose are converted to products like ethanol (CH3CH2OH) and carbon dioxide (CO2). This process is crucial in the production of various foods and beverages, such as bread, where the CO2 helps the dough rise, and beverages like wine and beer, where ethanol is the desired product. Fermentation enables these organisms to produce ATP via glycolysis, although it yields far less energy compared to aerobic respiration.
Chemical Reaction of Fermentation
The balanced chemical reaction for the fermentation of glucose is as follows: C6H12O6 →2 C2H5OH + 2 CO2. This equation illustrates how one glucose molecule is transformed into two molecules of ethanol and two molecules of carbon dioxide.