Gene Regulation Introduction

Genes do not operate to produce enzymes all the time. Each gene is normally more or less repressed (inactive); but, when a particular enzyme is needed, the relevant gene becomes active to bring about the production of that enzyme. A totally active gene can produce a very large amount of enzyme. If the synthesis of all the enzymes is fully accelerated in a cell, it would enter into a metabolic chaos. Thus, the phenomena of gene repression and derepression provide a means of decreasing or increasing the rate of synthesis of a particular enzyme in response to variations in the requirement of the enzyme. Every cell has a mechanism that controls the expression of a particular gene and thereby the amount of a particular enzyme at a particular time. The rate of protein synthesis is regulated by a genetic apparatus and environmental factors in accordance with the need of a cell. The mechanism that stimulates the expression of certain genes (synthesis of some polypeptides) and inhibits the expression of others is called regulation of gene expression (protein synthesis).