Question

Describe how gInA gene is regulated by nitrogen levels.

Answer 1

glnALG operon codes for structural gene glnA ( and also glnG).glnALG operon regulates nitrogen content of the cell.glnA gene encodes for gluamine synthatase,an enzyme that catalyses conversion of glutamate and ammonia to glutamine,thereby controlling nitrogen levels in cell.When nitrogen level is low in the cell glnALG operon is activated,as a result more more glutamine synthatase is encoded by glnA gene ,which produces more glutamine.Nitrogen content is directly proportional to ratio of concentration of glutamine to 2 ketoglutarate.So nitrogen levels increase in cell when this operon is activated.Thus glnA gene is regulated by nitrogen levels. That is this gene is expressed to produce glutamine synthatase when nitrogen level is low and not expressed when nitrogen level is high in cell(operon is repressed in this case).