Yeast cells. Coloured Scanning Electron Micrograph (SEM) of a colony of yeast cells, Saccharomyces cerevisiae. This fungus, also known as Baker's or Brewer's yeast, consists of single vegetative cells. Some cells can be seen dividing by rapidly budding off new cells. Saccharomyces cerevisiae is able to ferment sugar, producing alcohol and carbon dioxide in the process. It has long been used in the brewing of beer, the production of wine and in baking leavened bread (carbon dioxide causes the dough to rise). Medically, dried Baker's yeast is used as a rich source of vitamin B1, riboflavin and nicotinic acid. Magnification: x500 at 6x7cm size. x800 at 4x5"~LANDSCAPE"