Yeast makes bread, beer and wine. And like us, yeast can reproduce sexually. A mother and father cell merges and a large cell which contains four offspring. When environmental conditions are favorable, the offspring are released, as shown here. Yeasts are also a popular subject of study for scientists. Yeast research has yielded vast knowledge of basic cellular and molecular biology as well as a myriad of human diseases, including colon cancer and various metabolic disorders.