Saccharomyces cerevisiae  Saccharomyces cerevisiae () is a species of yeast. It has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have been originally isolated from the skin of grapes (one can see the yeast as a component of the thin white film on the skins of some dark-colored fruits such as plums; it exists among the waxes of the cuticle). It is one of the most intensively studied eukaryotic model organisms in molecular and cell biology, much like "Escherichia coli" as the model bacterium. It is the microorganism behind the most common type of fermentation. "S. cerevisiae" cells are round to ovoid, 5–10 μm in diameter. It reproduces by budding. Many proteins important in human biology were first discovered by studying their homologs in yeast; these proteins include cell cycle proteins, signaling proteins, and protein-processing enzymes. "S. cerevisiae" is currently the only yeast cell known to have Berkeley bodies present, which are involved in particular secretory pathways. Antibodies against "S. cerevisiae" are found in 60–70% of patients with Crohn's disease and 10–15% of patients with ulcerative colitis (and 8% of healthy controls). "S. cerevisiae" has been found to contribute to the smell of bread; the proline and ornithine present in yeast are precursors of the 2-Acetyl-1-pyrroline, a roast‐smelling odorant, in the bread crust. Sup35، the single protein which forms (PSI+) prion in yeast "Sarcomycess varisenes", can form a different amyloid with different structure and stability. Sup35's functions include different defense strategies against stress in yeast. N-terminal and middle reagin (NM) of Sup35 have polar amino acids, such as glutamine and glycine, and can control stress-sensing capability and facilitate the phase separation of Sup35 into large quantities of molecular condensates. It is required for Sup35 to be misfiled and enter to aggregation {PSI+} prion region. Under stress, Sup35 forms a protective gel followed by gelatin, and promotes the yeast cell more fitness. When we deprive yeast of energy (glucose)! Sup35 assembles into small particles which protect yeast and present in arrested state and stationary phase but dissolved after cell were supplied in fresh media.