Question

Briefly describe how cells determine whether or not to express genes in the his operon. Be sure to include the mechanism for why expression occurs or does not occur.

Answer 1

The operon is a functional unit of get containing a cluster of genes. These genes are controlled by single promotor , and operator. Most of the time the gene contained in the operon are the genes usually expressed at the same time. suppose if the gene corresponding to an antibiotic resistance or the heat shock protein are to be expressed at a certain time. As these genes are not needed all the time the repressor protein is bound to the operator region and the polymerase could not bind to the promotor. Which allows the genes not to be expressed. When there is a need of those gene to be expressed. The repressor protein is released from the operator region by different means (phosphorilation / dephosphorilation / presence of certain compound) and the successful expression of gene happens.

Ex: Like in Lac operon the repressor protein is bound to the operator region and the presence of allolactose or biosimilar compound like IPTG removes the repressor protein and carries the successful transcription of gene and gene expression.