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Question #46404
The Question
Both the lac operon's regulatory mechanism and the biocontrol efficacy of Baculoviruses (genus Nucleopolyhedrovirus) rely on precise molecular recognition. Which of the following statements regarding the breakdown or function of these specificities is INCORRECT?
Options
- A.
A mutation in the lac operator that prevents repressor binding leads to constitutive expression of the structural genes, regardless of lactose availability.
- B.
The ecological utility of Nucleopolyhedrovirus in Integrated Pest Management (IPM) stems from its broad-spectrum host range, allowing it to target multiple non-related insect orders simultaneously.
- C.
The inability of the lac repressor to bind the operator in the presence of an inducer is due to a conformational change, demonstrating highly specific allosteric regulation.
- D.
Baculoviruses exhibit no negative impacts on non-target insects or vertebrates because their viral attachment proteins require highly specific host cell receptors, analogous to repressor-operator specificity.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Operator|Promoter|Baculovirus|NPV
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often equate 'effective biocontrol' with 'killing all pests' (broad-spectrum).
However, NCERT strictly emphasizes that the true value of NPV in Integrated Pest Management (IPM) is its narrow-spectrum, species-specific nature, which preserves beneficial insects.
The question synthesizes this ecological specificity with the molecular specificity of the lac operon to test deep conceptual understanding of 'lock-and-key' biological systems.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Molecular Basis of Inheritance - Class 12 |
| Concept | Lac Operon Inducibility |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |