S. cerevisiae

Saccharomyces cerevisiae is type of yeast. It is a small, oval, single- celled organism that divides by budding to reproduce. It can divide existing as a haploid or diploid, depending on environment. S. cerevisiae is commonly used as baker's and brewer's yeast. It is part of the fungi kingdom and has a thick, waxy cell wall. The cells contain mitachondria but no chloroplasts. Alberts B., Johnson A., Lewis J., Raff M., Roberts K. and Walter P. (2008) Molecular Biology of the Cell, 5th Edition, New York: Garland Science. p33 Its genome was sequenced in 1997 and was the first eukaryotic organism to have its genome sequenced. Its genome is approximately 13Mb (Mb=millions of base pairs) and 6000 genes. Hartl D.L and Ruvolo M. (2012) Genetics: Analysis of Genes and Genomes, 8th Edition, Burlington: Jones and Bartlett Learning. p34 It has key characteristics which make it a useful model organism, a well established experimental biological system, for work in laboratories: *it is a unicellular eukaryote that can be studied under the microscope *it is small so is cheap and easy store *it grows rapidly in a simple nutrient medium, having an approximate generation time of 80 minutes *it can be genetically modified relatively easily, and has been extensively studied in the past, so lots is known about its genes. *it shares homology with humans and has been used specifically in the research of the cell division cycle, gene expression, DNA replication and repair and cell signalling *it has a large mutant collection *it is non-pathogenic === References ===