The gas often recognized as a byproduct of anaerobic cellular respiration is carbon dioxide (CO2). This type of respiration occurs in environments lacking oxygen, leading organisms such as yeast and some bacteria to convert glucose into energy through fermentation processes. In alcohol fermentation, for example, glucose is broken down into ethanol and carbon dioxide. The release of carbon dioxide contributes to processes like bread rising and is critical in various industrial applications, including brewing and biofuel production. Understanding anaerobic processes is vital for microbiology and ecology.