"Journey to the Microcosmos: The Microbe You Eat All the Time" explores yeast as a microscopic fungus central to bread, beer, and wine. The video explains key biology concepts including Saccharomyces cerevisiae, asexual reproduction by budding, metabolism, and alcoholic fermentation, showing how yeast converts sugars into energy, carbon dioxide, and ethanol. It also traces the history of fermentation from ancient China and Egypt to major scientific discoveries by Louis Pasteur, linking yeast research to germ theory, genetics, and modern biotechnology. With connections to microbiology, chemistry, world history, and food science, this overview supports curriculum topics on living organisms, scientific inquiry, and the cultural importance of microbes. Part of the "Journey to the Microcosmos" series.