Question

What is gene control and why is gene control important?

Answer 1

In other words we can call gene control as regulation of gene expression. The cells transcribe and translate proteins whenever necessary, be it prokaryotic or eukaryotic cell, protein synthesis is not a continuous process. Rather, protein synthesis occurs at specific intervals whenever required and at the rest of the time genes remain silent, i.e. no expression occurs. Thus, the cell regulates and controls the expression of a specific gene at a specific time to express a specific protein and this is the basis of proper functioning of metabolism in all organisms.

Gene control is important to save energy and to avoid unnecessary crosstalk inside a cell. in a chromosome, there remains codes for several genes, which are separated by introns in case of eukaryotes; in prokaryotes there are operon systems where several genes remain under a single promoter and transcribe together to save time of transcription and translation s prokaryotic life span is shorter.

In eukaryotes, a mechanism called intron splicing occurs to make agene multitalented, so that the gene can give a new solution to every different requirements coming on its way by alternative splicing mechanism. The gene is transcribed first to mRNA which has both introns and exons in it, now the cell decides which protein to translater from this segment of mRNA by alternative splicing of introns. This is called transcriptional control.

In prokaryotes, different types of operons are found which contain structural genes, regulator genes, operator genes etc. Regulator and operator genes control expression of structural genes in bacterial operons. A very common example is lactose operon in bacteria, where presence of lactose induce the expression of Lac Operon genes in bacteria, which otherwise remain switched off. Bacteria can survive well in glucose as carbohydrate source but whenever there is scarcity of glucose and presence of lactose in the media; bacteria need to express the enzymes required for Lactose metabolism. Thus, the proper control over gene expression is required in both prokaryotes and eukaryotes for better thriving in harsh life situations.