A mutant strain of E. coli produces beta-galactosidase in the presence and in th

Question

A mutant strain of E. coli produces beta-galactosidase in the presence and in the absence of lactose. Where in the operon might the mutation in this strain occur and why? in the CAP binding site, where the mutation leads to the inefficiency of RNA polymerase activity. in the operator region, which leads to increased binding of the lac repressor to the operator in the promoter region of the operon, where the mutation leads to the failure of the RNA polymerase to bind to the promoter in the operator region, where the mutation leads to the failure of the operator to normally bind the repressor in the lac gene, which leads to an inactive lac repressor near the lacl gene, where the mutation leads to increased levels of lac repressor being made There are two correct locations. In the absence of lactose, the Lac repressor protein binds the operator and prevents transcription from occurring, and no beta-galactosidase is made.

Explanation / Answer

A mutation strain of E.coli is producing Beta galactosidase even in the absence of lactose. Normally, In the absence of lactose, the Lac repressor protein binds the operator and prevents transcription from occuring, and no beta galactosidase is made.

The mutation has occurred in the following regions:

1. Within the operon, the operator region is the most probable location of the mutation. If the mutation prevents the lac repressor protein from binding to the operator, then transcription of the lac structural genes will not be inhibited. Expression will be constitutive.

2. Outside of the operon, a mutation in the lacI gene that inactives the repressor or keeps it from binding to the operator could also lead to constitutive expression of the structural genes.

Therefore the two correct answers are (if you label the options as a,b,c,d,e and f) - d and e.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.