Yeasts are tiny, single-celled fungi that play a crucial role in many processes, especially in baking and brewing. They are responsible for fermentation, which is the process that converts sugars into alcohol and carbon dioxide. This is why yeasts are essential for making bread rise and for producing beverages like beer and wine. In addition to their culinary uses, yeasts are also important in science and medicine. They are used in research to understand cellular processes and genetics. Some types of yeasts can even be found in probiotics, which are beneficial for gut health. Overall, these microorganisms are vital to both our food and our understanding of biology.