The Lac Repressor Has Been Mutated So That Its Binding

question 73

Multiple Choice

The lac repressor has been mutated so that its binding site for the operator has been altered to the extent that it is unable to bind to the operator.What is the likely effect of this mutation on the lac operon?

• A) The repressor will be unable to bind to the operator; the operon will bind RNA polymerase and it will thus be turned on.
• B) The repressor will bind to the operator despite the mutation, and will suppress transcription of the operon in the presence and absence of lactose.
• C) The lac operon will be protected by the altered repressor.
• D) The repressor will be unable to bind to the operator; therefore, the ability of RNA polymerase to bind there will be severely hampered.

---

Definitions:

Skeletal Muscle Tissue

A type of muscular tissue attached to bones, responsible for voluntary movements of the body through contraction and relaxation.

Striated

Having a series of ridges, stripes, or lines, often related to muscle tissue that appears striped under a microscope due to the arrangement of myofilaments.

Endomysium

Fine connective tissue sheath surrounding each muscle fiber.