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Question #46564
The Question
During the industrial production of a specific enzyme using a bacterial culture grown on a complex polysaccharide medium, a technician continuously adds high concentrations of glucose to maximize biomass. Surprisingly, the yield of the target enzyme drops to near zero. Based on the principles of genetic regulation, which of the following best explains this phenomenon?
Options
- A.
Glucose acts as a corepressor, binding to the constitutive repressor protein and increasing its affinity for the operator region.
- B.
High glucose levels decrease intracellular cAMP, preventing the formation of the CAP-cAMP complex required for RNA polymerase to bind the promoter.
- C.
Continuous glucose addition competitively inhibits the permease enzyme, preventing the entry of the complex polysaccharide into the cell.
- D.
Glucose induces the i-gene to overproduce the repressor protein, which permanently blocks the transcription of the required structural genes.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Household_Product_Fermentation|Lac_Operon_Inducibility|Glucose_Repression
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the negative regulation of operons (e.g., lactose removing the repressor) but overlook the positive regulation mechanism.
The trap lies in assuming that as long as the alternative substrate is present, the operon will be active.
However, the presence of glucose exerts a dominant 'veto' via catabolite repression (low cAMP), stalling the production of enzymes needed for non-sugar substrate breakdown.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Microbes in Human Welfare - Class 12 |
| Concept | Household Product Fermentation Specificity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |