Question

The Lac-Operon model was elucidated by

• A. Jacob and Crick
• B. Watson and Crick
• C. Francois Jacob and Jaques Monad
• D. Hershey and Chase

Answer 1

The Correct Option is C

• The Lac operon model was proposed by François Jacob and Jacques Monod in 1961.
• This model explains the regulation of lactose metabolism in bacteria, specifically in Escherichia coli (E. coli).
• The Lac operon consists of a promoter (where RNA polymerase binds to initiate transcription), an operator (a regulatory region where the repressor protein binds), and structural genes that code for enzymes involved in lactose metabolism (e.g., lacZ, lacY, and lacA).

Key points of the Lac operon model:

• Induction: The presence of lactose causes the repressor to detach from the operator, allowing the RNA polymerase to transcribe the structural genes and thus produce enzymes needed to metabolize lactose.
• Repression: In the absence of lactose, the repressor protein binds to the operator and blocks transcription, preventing unnecessary production of the enzymes.
• The discovery of the Lac operon model helped in understanding gene regulation and enzyme synthesis in prokaryotic cells.
• Jacob and Monod's work was significant in the field of molecular biology and earned them the Nobel Prize in Physiology or Medicine in 1965.

Thus, the Lac operon model was elucidated by François Jacob and Jacques Monod.

The correct answer is (C) : Francois Jacob and Jaques Monad.

Answer 2

The Lac Operon model is a crucial concept in molecular biology that explains the regulation of gene expression in prokaryotes, specifically in Escherichia coli. This model was elucidated by Francois Jacob and Jacques Monod in 1961, offering a groundbreaking insight into how genes can be turned on or off in response to environmental changes.

The Lac operon is a system that controls the metabolism of lactose in bacteria. It consists of several key components:

• Structural genes: These genes encode enzymes necessary for lactose metabolism.
• Promoter: The site where RNA polymerase binds to initiate transcription.
• Operator: A regulatory region where repressor proteins bind to inhibit transcription.
• Repressor protein: A protein that, when bound to the operator, prevents transcription of the operon's genes.
• Inducer (Lactose): Lactose or its derivative allolactose acts as an inducer by binding to the repressor, causing it to release from the operator, thus allowing gene transcription.

Jacob and Monod's research led to the discovery of negative and positive regulation mechanisms in gene expression, with the Lac operon serving as a classic example of how cells adapt to their environment by regulating the synthesis of enzymes based on the presence or absence of lactose.

The correct answer is: (C) Francois Jacob and Jacques Monod.

Their work on the Lac operon laid the foundation for our understanding of genetic regulation and earned them the Nobel Prize in Physiology or Medicine in 1965.