Chapter 8, Problem 8Q

Summary Introduction

To determine: If ArgR is a repressor protein, whether it would be expected to bind more tightly or less tightly to DNA sequences when arginine is abundant.

Introduction: Gene regulation is the process through which the cells control the expression of genes. There are mechanisms that control gene expression at different levels. In E. coli, an operon consists of the genes in a cluster and it is transcribed from a promoter. Inducible operons can be turned ‘on’ by inducer molecule, and its example is the lac operon. Repressible operons can be turned ‘off’ by corepressor molecule that activates repressor, and its example is the trp operon.

Summary Introduction

To determine: If ArgR is an activator protein, whether the binding of arginine would increase or decrease its affinity for its regulatory DNA sequences.

Introduction: Genes are sets of nucleotides that codes for a particular protein. The genes have to be expressed for the synthesis of a protein. Gene regulation is a process where the expression of genes is controlled for the synthesis of specified gene products (usually RNA or proteins). This gene expression is regulated depending on the requirement of the cell.