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Question #47677
The Question
A researcher subjects the nodulated root cortical cells of a leguminous plant to biolistic gene transfer. Following the procedure, the plant exhibits severe stunting and a complete halt in symbiotic nitrogen fixation, even though the nodules remain pink and anaerobic conditions are maintained. Based on metabolic trade-off theory, what is the most likely physiological cause for this cessation?
Options
- A.
The physical micro-trauma to the host cell membrane diverts the cellular ATP pool towards repair, starving the nitrogenase complex of the 16 ATP required per N2 molecule.
- B.
The high-velocity tungsten particles used in the gene gun competitively inhibit the Mo-Fe cofactor of the nitrogenase enzyme.
- C.
The physical perforation of the cell wall allows atmospheric oxygen to diffuse into the bacteroid, irreversibly inactivating the nitrogenase enzyme.
- D.
The transformation process directly inhibits the active transport of alpha-ketoglutaric acid, preventing the conversion of ammonia into amino acids.
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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
Symbiotic Nitrogen Fixation|Biolistics/Gene Gun Physics|ATP Synthase
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often hyper-focus on the oxygen sensitivity of nitrogenase (the 'pink nodule' trap) but overlook its massive energy dependency (16 ATP per N2).
This question tests the ability to link a biotechnological procedure (biolistics causing physical membrane damage) to a physiological metabolic drain, recognizing that ATP is a finite cellular resource shared between host repair mechanisms and symbiotic bacteroid metabolism.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Microbes in Human Welfare - Class 12 |
| Concept | Symbiotic Nitrogen Fixation |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |