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

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

The correct

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.

an individual’s sex (i.e., whether they are a male or female) is determined by the sex chromosomes. most people have two sex chromosomes, one that is inherited from their mother and one that is inherited from their father. typically, females have two x chromosomes (xx) and males have one x chromosome and one y chromosome (xy). conditions caused by changes (“mutations”) in genes located on the x chromosome are considered x-linked.

x-linked recessive inheritance

most x-linked conditions are recessive. this means that in a person with two x chromosomes (most females), both copies of a gene (i.e., one on each x chromosome) must have a change or mutation whereas in a person with one x chromosome (most males), only one copy of a gene must have a mutation. a female with a mutation in one copy of a gene on the x chromosome is said to be a “carrier” for an x-linked condition. a male with a mutation in a gene on the x chromosome is typically affected with the condition. because females have two copies of the x chromosome and males have only one x chromosome, x-linked recessive diseases are more common among males than females. however, x-linked recessive diseases can occur in both males and females.

for x-linked recessive disorders, an unaffected carrier mother who has a mutation in a gene on the x chromosome can transmit either the x chromosome with this mutation or a “normal” x chromosome to her children. if the father is unaffected, none of her daughters will be affected and all of her daughters will be unaffected—since they will inherit at least one normal x chromosome from their father. however, each daughter will have a 50% chance of being an unaffected carrier like her mother and a 50% chance of both x chromosomes being normal.