In the lac operon model, what is the primary role of the allolactose molecule?
Show answer & explanation
Correct answer: A
Explanation
Answer: It functions as an inducer, binding to the repressor protein and inactivating it.
Explanation: The lac operon is a gene regulation system studied in Molecular Biology, especially in bacteria like E. coli.
The molecule allolactose is formed from lactose.
It acts as an inducer in the lac operon.
Mechanism:
In the absence of lactose → repressor blocks gene expression
When lactose is present → allolactose binds to the repressor protein
This inactivates the repressor → genes for lactose metabolism are turned ON
Additional Key Facts
Structural genes in lac operon: lacZ, lacY, lacA
Repressor protein is encoded by the lacI gene
Operon model was proposed by François Jacob and Jacques Monod
It is a classic example of inducible gene regulation
Potential Exam Questions (with Answers)
Q. Which genes are involved in lactose metabolism in lac operon?
Ans: lacZ, lacY, lacA
Q. Who proposed the operon model?
Ans: François Jacob and Jacques Monod