Chapter 18 Regulation of Gene Expression Conducting the Genetic Orchestra Cells precisely regulate their gene expression. Both prokaryotes and eukaryotes must alter thaier patterns of gene expression in response to changes in the environment. Remember, each cell contains the same genetic information, but the liver cell and brain cell express very different proteins, etc. This chapter will look at how cells (bacteria, eukayotes, etc.) regulate expression of their genes. Point: in eukaryotes, the expression of a gene is often regulated at the level of transcription. Learn this. Point: disruptions in gene regulation can lead to cancer 18.1 Bacteria often respond to environmental change by regulating Transcription