You are examining the regulation of the lactose operon in Escherichia coli. You isolate a mutant strain that lacks the products of all three structural genes even when grown in the presence of inducer. You find that the mutation is trans - dominant over lacl + and lacl - mutations. This suggests that the mutation affects the:
lac repressor
lac permease
lac operator
lac promoter

Question

You are examining the regulation of the lactose operon in Escherichia coli. You isolate a mutant strain that lacks the products of all three structural genes even when grown in the presence of inducer. You find that the mutation is trans - dominant over lacl + and lacl - mutations. This suggests that the mutation affects the:
lac repressor
lac permease
lac operator
lac promoter

Accepted Answer

***A*** ∻Key Concept∻ ⚹Trans-dominant mutations⚹ ∻Explanation∻ ⚹A trans-dominant mutation suggests that the mutation affects a diffusible factor, such as the lac repressor, which can act on multiple operons within the cell. Since the mutation is dominant over both lacl+ (wild type) and lacl- (repressor-deficient) mutations, it likely alters the lac repressor's ability to regulate the operon in response to the inducer.⚹◊What type of mutation could cause a strain of Escherichia coli to lack the products of all three structural genes in the lactose operon, even in the presence of inducer?⍭ Generate me a similar question◊

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