Which of the following statements about lac operon in E. coli is true?
Which of the following statements about lac operon in E. coli is true?
The correct option is D Lac operon mRNA is a polycistronic mRNA
Lac operon is an operon responsible for metabolism and transport of lactose in E. coli and other bacteria. It has three structural genes (lac Z, lac Y, and lac A) regulated by a single promoter and a single mRNA is formed when these genes are transcribed. The mRNA produced by transcription carries information for the synthesis of all three proteins. Hence, it is a polycistronic mRNA.
Lac repressor is the molecule that binds to the operator region of the operon, thus it does not allow the RNA polymerase to bind to the DNA molecule.
Presence of lactose in a growth media acts as an inducer for lac operon, so growing E. coli in lactose medium will switch on the operon leading to the synthesis of proteins required for lactose metabolism.
When the lac repressor binds with the operator region it does not allow the RNA polymerase to bind the DNA thus preventing the switching on of the process of transcription.
Lac operon is an operon responsible for metabolism and transport of lactose in E. coli and other bacteria. It has three structural genes (lac Z, lac Y, and lac A) regulated by a single promoter and a single mRNA is formed when these genes are transcribed. The mRNA produced by transcription carries information for the synthesis of all three proteins. Hence, it is a polycistronic mRNA.
Lac repressor is the molecule that binds to the operator region of the operon, thus it does not allow the RNA polymerase to bind to the DNA molecule.
Presence of lactose in a growth media acts as an inducer for lac operon, so growing E. coli in lactose medium will switch on the operon leading to the synthesis of proteins required for lactose metabolism.
When the lac repressor binds with the operator region it does not allow the RNA polymerase to bind the DNA thus preventing the switching on of the process of transcription.
