Biotechnology and Bioinformatics (1+1)

1.3.1. Introduction

If an organism is to survive the processes that enable information to be copied from gene s and then used to synthesize protein s must be regulated. Different cells within an organism share the same set of chromosomes. In each cell some genes are active while others are not. For example, in humans only red blood cells manufacture the protein hemoglobin and only pancreas cells make the digestive enzyme known as trypsin, even though both types of cells contain the genes to produce both hemoglobin and trypsin. Each cell produces different proteins according to its needs so that it does not waste energy by producing proteins that will not be used.

A variety of mechanisms regulate gene activity in cells. One method involves turning on or off gene transcription , sometimes by blocking the action of RNA polymerase , an enzyme that initiates transcription.

Gene regulation may also involve mechanisms that slow or speed the rate of transcription, using specialized regulatory proteins that bind to DNA. Depending on an organism’s particular needs, one regulatory protein may spur transcription for a particular protein, and later, another regulatory protein may slow or halt transcription.