Genetic mutations provide valuable tools for analyzing biochemical pathways in yeast. In this module, students use deletion mutants to analyze the steps in methionine biosynthesis in Saccharomyces cerevisiae. At the end of this module, students will be able to:understand and use the correct genetic nomenclature for genes, proteins and mutant strainsexplain how genetic screens are used to isolate mutant strains with particular phenotypesdistinguish various met deletion strains by their ability to grow on selective media containing different sulfur sources and by their appearnace on indicator mediapredict how mutations in various MET genes will affect the intracellular concentrations of intermediates in the methionine biosynthesis This module is part of a semester-long introductory lab class, Investigations in Molecular Cell BIology, at Boston College.