A species of yeast which is an important model organism for biological study, particularly for genetics and molecular biology. The entire genome of this species has been base sequenced and it is used to do research on the basic cellular mechanics of replication, recombination, cell division and metabolism. S. cerevisiae is also economically important in the food industry, where it is used to ferment grain sugars to make beer and as baker's yeast for baking bread or making other food which requires rising by gas bubbles of carbon dioxide. It is also sometimes taken as a vitamin supplement for protein, the B vitamins, and folic acid.