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Question #47757
The Question
In a large-scale stirred-tank bioreactor, a recombinant protein is being produced by E. coli using a lac promoter-driven vector. To maximize biomass, a concentrated glucose feed is introduced during the exponential phase. However, due to poor bioreactor geometry, the fluid mixing is non-homogenous. What will be the most likely molecular consequence of this uneven glucose distribution on the recombinant yield?
Options
- A.
Localized high-glucose zones will lower cAMP levels, preventing CAP-cAMP complex formation and causing mosaic repression of the transgene.
- B.
Uneven mixing will create high-glucose zones that directly activate the lac repressor protein, completely halting recombinant protein synthesis.
- C.
Localized low-glucose zones will undergo carbon catabolite repression, leading to the premature degradation of the recombinant mRNA.
- D.
The non-homogenous distribution will cause glucose to competitively bind the operator region, blocking RNA polymerase in localized zones.
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
Taq Polymerase|DNA Polymerase Directionality|DNA Ligase Polarity
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: This question requires the synthesis of two distinct NCERT chapters: 'Biotechnology: Principles and Processes' (importance of homogenous mixing in bioreactors) and 'Molecular Basis of Inheritance' (regulation of the lac operon).
The common misconception is confusing the negative regulation of the lac operon (repressor binding to the operator) with its positive regulation (glucose lowering cAMP, preventing CAP binding).
Students must recognize that glucose induces 'Catabolite Repression' via the CAP-cAMP pathway, not by interacting with the repressor or operator.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biotechnology : Principles and Processes - Class 12 |
| Concept | Taq Polymerase Thermal Stability |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |