Question

Match the components of lac operon of E. coli with their functions. Choose the answer with the correct combination of alphabets of the two columns.

Answer 1

The gene that codes for any RNA/protein product, which does not serve as regulatory protein but serves as enzymes, are known as structural genes. The lac z, lac y and lac genes in lac operon are the structural genes. The operator is a DNA sequence present between the promoter region and the first coding gene. This operator region serves as the repressor protein binding site. The promoter is a DNA segment that serves to initiate transcription of a particular gene. They are present upstream near the transcription start sites of genes and serve as the binding site for RNA polymerase. Regulator gene regulates the expression of structural genes by its protein product that is mostly transcription factors. These transcription factors, also called as a repressor, bind to the operator region which is located just upstream the binding site of the RNA polymerase and hence, prevent the binding and transcription.