This set, particularly dedicated to the 10th grade, is designed for a fast implementation. Ideal for an introduction to the basic techniques of microorganisms cultures. By changing the environmental parameters of the Saccharomyces cerevisiae yeast ADE2 culture, the student will demonstrate experimentally that the expression of a gene is subject to environmental factors. Thus, he will be able to change the content of adenine and/or create anaerobic conditions and then compare the results with the witness box.The ADE2 yeast on complete medium, uses an adenine biosynthetic chain which carries a mutation leading to the accumulation of a red pigment. In environment highlt rich in adenine (provided by the pellet), the yeasts do not use this biosynthetic pathway: the colonies therefore find a usual beige color /cream. A kit consists of a strain box for transplanting (S. cerevisiae ADE 2) + 20 pellets of adenine ready to use + Petri dishes + the YPG culture medium.