Question

true/false. Operons are structures in bacterial genomes that organize genes involved in a common metabolic pathway. A specific example is the lac operon, which produces three enzymes involved in the metabolism of lactose (milk sugar) as a food source for Escherichia coli. Identify the functions of each part of the operon and related structures.Operons are structures in bacterial genomes that organize genes involved in a common metabolic pathway. A specific example is the lac operon, which produces three enzymes involved in the metabolism of lactose (milk sugar) as a food source for Escherichia coli. Identify the functions of each part of the operon and related structures.

Answer 1

true, The lac operon consists of three structural genes, lacZ, lacY, and lacA, and their related regulatory elements, such as the promoter, operator, and repressor. The promoter is the site on the operon where RNA polymerase binds to initiate gene transcription. The operator is a small segment of DNA on the operon where the repressor binds, inactivating gene expression of the lac operon. The repressor gene (also lacI gene) transcribes a gene that codes for the repressor protein that attaches to the operator, preventing transcription of the lac operon to take place. The lacZ gene transcribes a gene that codes for an enzyme called beta-galactosidase, which splits the disaccharide lactose into the monosaccharides glucose and galactose. The lacY gene transcribes a gene that codes for an enzyme called permease, which lets lactose sugars enter into the bacterial cell. The lacA gene transcribes a gene that codes for an enzyme called transacetylase, which helps to clean up any toxic metabolic byproducts of lactose metabolism. Lastly, the terminator represents the endpoint of the lac operon gene segment.