Question

We studied a dominant mutation for the lac operon’s gene for the lac repressor. Which description...

We studied a dominant mutation for the lac operon’s gene for the lac repressor. Which description below best explains why the mutation is dominant?

Select one:

If the mutant repressor cannot bind DNA the lac operon is derepressed even in the presence of a second copy of the repressor gene that is wild type.

If the mutant repressor protein cannot bind lactose it represses the expression of the lac operon even in the presence of a second copy of the repressor gene that is wild type.

If the mutant repressor cannot bind DNA the lac operon is derepressed even in the presence of a second copy of the repressor that cannot bind lactose.

If the mutant repressor protein cannot bind lactose it represses the expression of the lac operon even in the presence of a mutation in the O site of the lac operon.

If the mutant repressor cannot bind DNA, the lac operon is derepressed even in the presence of a mutation in the promoter sequenc

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Homework Answers

Answer #1

Option b is the best suited according to the situation given in the question

If the mutant repressor protein cannot bind lactose it represses the expression of the lac operon even in the presence of a second copy of the repressor gene that is wild type.

Explanation-

Here repressor is not able to bind with lactose, means it always bind to operator of DNA and repress expression of lac operon. Although second copy is wild but first copy due to mutation always binds to operator site and will always repress the lac operon.

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