Question

The diagram represents a segment of the E. coli chromosome that contains

the lacl gene and part of the lac operon, a coordinately regulated set of
genes that are required for the metabolism of lactose. The presence of
lactose, which causes the repressor to be released from the operator,
results in increased transcription of the lac operon.
6. Which of the answer choices below is the most likely consequence of a
mutation at the operator locus that prevents binding of the repressor
protein?

Answer 1

The most likely consequence of a mutation at the operator locus that prevents binding of the repressor protein would be the continuous transcription of the lac operon genes. The repressor protein binds to the operator and prevents the RNA polymerase from transcribing the lac operon genes. If the repressor protein is not bound to the operator, the RNA polymerase will continuously transcribe the lac operon genes even in the absence of lactose. Therefore, the correct answer is:

• Continuous transcription of the lac operon genes