Question

A mutant E. coli strain does not express lacZ, even in the presence of lactose. What is a possible genotype of the cells?

Answer 1

Answer:

The answer is "$\bold{lacI^{+} lacP^{+} lacO^{+} lacZ^{-} lacY^{-} lacA^{+}}$ "

Explanation:

In this question, the prescribed mutant E. Coli does not express the lacZ gene, so beta-galactosidase doesn't quite exist. Therefore in a particular strain, there is also the potential of lacZ– and that only the genetic makeup indicates its production of lactose. Therefore the above-mentioned option is correct.