Question

Which of the following mutations could lead to constitutive expression of the genes of the lac operon? View Available Hint(s) Which of the following mutations could lead to constitutive expression of the genes of the lac operon? A mutation in the lac-Z gene A mutation in the lac-Y gene A mutation in the operator sequence A super repressor mutation Submit Part B Which of the following best describes the biological role of the lac operon? View Available Hint(s) Which of the following best describes the biological role of the lac operon? It ensures that bacterial cells produce lactose only when no other food sources are available. It ensures that a cell dedicates resources to the production of enzymes involved in lactose metabolism only when lactose is available in the environment. It ensures that a cell produces enzymes involved in lactose metabolism in a constitutive manner. It prevents other sugars from being metabolized until all available lactose has been used. Submit Part C The placement of the operator sequence between the promotor and the structural genes is critical to the proper function of the lac operon. View Available Hint(s) The placement of the operator sequence between the promotor and the structural genes is critical to the proper function of the lac operon. True False

Answer 1

Options for part A are as follows:

A) A mutation in the operator sequence

B) A mutation in the lac-Z gene

C) A mutation in the lac-Y gene

D) A super repressor mutation

Answer:

The correct answer:

Part a - A mutation in the operator sequence

Part b - It ensures that a cell dedicates resources to the production of enzymes involved in lactose metabolism only when lactose is available in the environment

Part C. true.

Explanation:

part a:

If there is a mutation in the operator sequence leads to prevent binding of the repressor which leads to allowing constitutive expression of the genes various conditions.

part b:

The biological role of the lac operon makes sure that the cell dedicates resources to the production of enzymes involved in lactose metabolism only when lactose is available in the environment

Part c:

RNA polymerase cannot transcribe the structural genes due to the repressor binds to the lac operator, therefore, the proper function of the lac operon is possible when the placement of the operator sequence between the promotor and the structural genes.