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Question #47656
The Question
In an E. coli culture, the exhaustion of glucose from the medium triggers a shift in metabolic flux towards lactose utilization. Which of the following statements regarding this metabolic and transcriptional transition is INCORRECT?
Options
- A.
A drop in glucose concentration increases intracellular cAMP levels, forming a complex that acts as a positive regulator of the operon.
- B.
The CAP-cAMP complex binds directly to the operator region, physically assisting RNA polymerase in initiating transcription.
- C.
The repressor protein, synthesized constitutively by the i gene, undergoes a conformational change upon binding with the inducer allolactose.
- D.
The metabolic shift requires the translation of the lacY gene to produce permease, which increases cellular permeability to beta-galactosides.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Glucose | cAMP | CAP-cAMP Complex | Glycolytic Enzymes
Why This Question Is Tricky
Common Mistakes
Location Specificity Trap: Students often memorize that the CAP-cAMP complex 'turns on' the operon and the repressor 'turns it off', but fail to distinguish their exact binding loci.
The conceptual pivot relies on mapping regulatory proteins to their precise DNA sequences (CAP to Promoter vs.
Repressor to Operator).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Respiration in Plants - Class 11 |
| Concept | Glycolysis Redox Balance |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |