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Question #47687
The Question
Which of the following statements correctly distinguishes the genetic regulatory mechanism of the lac operon from the pharmacological action of statins?
Options
- A.
The lac operon is regulated by an inducer that competitively binds to the operator, whereas statins non-competitively inhibit the enzyme for cholesterol synthesis.
- B.
The lac repressor is inactivated via an allosteric conformational change upon binding allolactose, whereas statins act as competitive inhibitors at the active site of their target enzyme.
- C.
Both mechanisms represent negative feedback inhibition where the accumulation of a metabolic product directly halts the transcription of its respective pathway.
- D.
The lac operon demonstrates positive regulation by a constitutively synthesized repressor, while statins demonstrate negative regulation by degrading the target enzyme.
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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
Bacillus_thuringiensis|Alkaline pH|Midgut epithelium
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Differentiating between levels of metabolic control (Transcriptional vs.
Enzymatic) and binding mechanisms (Allosteric vs.
Competitive).
Students often misapply 'competitive inhibition' to the lac operon inducer-repressor dynamic, failing to realize the inducer causes an allosteric shift rather than competing for the DNA operator site.
Furthermore, NCERT explicitly defines statins as competitive inhibitors, making any option labeling them as non-competitive or transcriptional regulators incorrect.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Microbes in Human Welfare - Class 12 |
| Concept | Bioactive Molecule Origin |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |