What is Yeast?
{{Taxobox | name = ''Yeast'' | image = S cerevisiae under DIC microscopy.jpg | image_width = 250px | image_caption = Yeast cells under a [[microscope]]. | image2 = Simple diagram of yeast cell (en).svg | image2_width = 250px | image2_caption = A diagram of a typical yeast cell | domain = [[Eukaryote|Eukaryota]] | regnum = [[Fungus|Fungi]] | subdivision_ranks = Typical divisions | subdivision = <div> '''[[Ascomycota]]''' <small>(sac fungi)</small> * [[Saccharomycotina]] <small>(true yeasts)</small> * [[Taphrinomycotina]] ** [[Schizosaccharomycetes]] <small>(fission yeasts)</small> </div> }} '''Yeast''' are [[microorganism]]s. They are single-[[cell]]ed [[fungi]]. There are about 1,500 different [[species]] of yeast. Most reproduce [[asexual reproduction|asexually]], by [[budding]]. Some use [[binary fission]] to reproduce asexually. A particular [[species]] of yeast, '''''Saccharomyces cerevisiae''''', has been used for thousands of years. It is used for baking [[bread]] because the yeast makes [[carbon dioxide]] as a by-product of it eating sugar, which helps the bread rise ([[Leavening agent|leaven]]). Yeast is also used for making [[beer]] and other [[alcoholic drink]]s by a process known as [[fermentation]]. This process produces both [[Ethanol|ethyl alcohol]] and carbon dioxide. Ethanol is also used as [[fuel]], and to make other [[organic chemical]]s. Yeast can be used to make [[electricity]]. Yeast is also a [[model organism]] for studying [[cell biology]]. Some yeasts can cause [[infection]]s in [[human]]s (they are [[pathogen]]s). <gallery> Image:Compressed fresh yeast - 1.jpg|A block of fresh yeast Image:Dry yeast.jpg|Dry yeast (usually, yeast is sold like this) </gallery> ==Related pages== * [[Mycorrhiza]] * [[Mould]] * [[Slime mould]] * [[Lichen]] * ''[[Candida]]'' * [[Fungus]] ==References== {{reflist}} ==Other websites== {{commonscat-inline}} {{Mycoses}} {{Fungus}} {{biology-stub}} [[Category:Fungi]]