Scientific name -Kingdom- Fungi, Phylum- Ascomycota Class- Ascomycetes Order- Saccharomycetaler, Family- Saccharomycetaceae, Genus- Saccharomyces, Species- CervisiaeDescription - Yeast is a unicellular organism that lacks chloroplasts. They are so small that it can't be seen by the naked eye and they are so small that it would take 4000 of them lined up side by side to measure an inch. Habitat - Yeast lives on and is nourished by dead or living plant or animal matter. The ideal conditions of yeast is high humidity and temperature, plus lots of food. In bad conditions though the yeast produces a second cell wall for protection and the yeast contents divides into four parts; the parts are called ascospores. Then when favorable conditions return the ascospores burst to reproduce. Yeast gets their food from simple sugars, such as prutrose and destrose. These sugars are found in grapes and other fruits. They abstract the sugars out of the fruit by breaking the fruit down to double sugars then breaking those down to simple sugars. In this process they produce alcohol and CO2.Life cycle - Yeast reproduces by budding. This is where the adult yeast begins to swell on its surface. Then part of the parent begins to bud and a wall is formed between the parent and the new yeast. Then the new yeast may do one of two things. It may break away from the parent or it may stay attached to form a chain or a cluster. Budding is very quick. It takes about 20 minutes to produce new yeast.Importance - Yeast is used in many different types of commercial uses. Some of them are in banking to get breads and cakes to rise, in beer production in Germany, and wine production. Wine producers don't use wild yeast because they have some unfavorable traits. So they kill off the wild yeast and use yeast that have been domesticated to the needs of the production process.Bibliography - Stew Scherer "Yeast.com", Yahoo, Windows 95, 2-11-99