The ability of bacteria to survive in a variety of environments depends on their ability to regulate gene expression in response to various environmental signals. In this module, students will learn how proteins regulate transcription by their interaction with DNA, resulting in changes in metabolism, transposition, differentiation and phage. Particular attention is paid to the process of transcription by RNA polymerase, the role of sigma factors in controlling transcription specificity how environmental signals are transmitted across the cytoplasmic membrane, and the way that sequential expression of sigma factors determines cascades of gene expression during differentiation. This module introduces students to (i) the different levels of regulation during gene expression in bacteria and the mechanisms whereby control is exerted (ii) current methods for studying gene expression and regulation. It also provides opportunities for students to prepare work based on original scientific literature, and to present the material through formal delivery and informal discussion. Student's problem solving ability is developed through data handling classes.