Chapter 28, Problem 3P

(a)

Summary Introduction

To explain:  The effect on gene expression in the lac operon of a mutation in lac operator that deletes most of $O_1$

Introduction:

The $lacI\text{gene}$ codes for the repressor molecule which negatively regulates the Lac operon, by binding to $lac{O}_1,$ $O_2$, and $O_3$ operator. Binding of repressor molecule prevents the initiation of transcription, whereas binding of inducer to the repressor increase the efficiency of transcription.

(b)

Summary Introduction

To explain: The effect on gene expression in the lac operon of a mutation in $lacI\text{gene}$ that inactivates the repressor

Introduction:

The $lacI\text{gene}$ codes for the repressor molecule which negatively regulates the Lac operon, by binding to $lac{O}_1$ , $O_2$, and $O_3$ operator. Binding of repressor molecule prevents the initiation of transcription, whereas binding of inducer to the repressor increase the efficiency of transcription.

(c)

Summary Introduction

To determine: The effect on gene expression in the lac operon of a mutation in the promoter that alters the region around position $-10$

Introduction:

The $lacI\text{gene}$ codes for the repressor molecule which negatively regulates the Lac operon, by binding to the $lac{O}_1$, $O_2$ and $O_3$ operator. Binding of repressor molecule prevents the initiation of transcription, whereas binding of inducer to the repressor increase the efficiency of transcription.