Yeast fermentation is a biological process where yeast, a type of fungus, converts sugars into alcohol and carbon dioxide. This process occurs in anaerobic conditions, meaning it takes place without oxygen. Yeast cells consume sugars from various sources, such as fruits or grains, and produce ethanol, which is the alcohol found in beverages like beer and wine, as well as carbon dioxide, which can create bubbles in bread. Fermentation is essential in many food and beverage industries. In baking, for example, the carbon dioxide produced by yeast helps dough rise, resulting in light and fluffy bread. Additionally, in the production of alcoholic beverages, fermentation is crucial for creating the desired flavors and alcohol content.