To date,several lactose metabolism mutants have been found in Escherichia coli.One of these mutants has a phenotype in which the cell cannot accumulate lactose because no lactose permease protein is present.What genotype would be associated with this mutation?
A)lacZ⁻
B)lacY⁻
C)lacI⁻

Question

Quizplus · Accepted Answer

The lacY gene encodes for the lactose permease protein which is responsible for the transport of lactose into the cell. Therefore, a mutant lacking the lactose permease would have a deficiency in the lacY gene. The lacZ gene encodes for beta-galactosidase which is responsible for lactose breakdown, and the lacI gene encodes for the lac repressor protein which regulates the lac operon. Mutations in these genes would not lead to a lactose permease deficiency.

To Date,several Lactose Metabolism Mutants Have Been Found in Escherichia