BIO207H5 Chapter Notes -His3, Sickle-Cell Disease, Histidine
Document Summary
In this lecture we are going to consider experiments on yeast, a very useful organism for genetic study. Yeast is more properly known as saccharomyces cerevisiae, which is the single-celled microbe used to make bread and beer. Yeast can exist as haploids of either mating type (mat ) or mating type aaaaa (mataaaaa). Haploid cells of different mating type when mixed together will mate to make a diploid cell. Haploids and diploids are isomorphic meaning that a given mutation will cause essentially the same change in haploid and diploid cells. This allows us to look at the effect of having two different alleles in the same (diploid) cell. All yeast needs to grow are salts, minerals, and glucose (minimal medium). From these compounds, yeast cells can synthesize all of the molecules such as amino acids and nucleotides that are needed to construct a cell. The synthesis of complicated molecules requires many enzymatic steps.
