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Question #45180
The Question
A transgenic tobacco plant is engineered to express nematode-specific genes to initiate RNA interference (RNAi). Due to the use of a highly active constitutive promoter, the plant allocates an abnormally high amount of cellular energy towards synthesizing massive quantities of sense and antisense RNAs. Which of the following represents the most direct ecological consequence of this metabolic load on the local food web?
Options
- A.
The plant's Gross Primary Productivity (GPP) increases proportionally to support the RNAi mechanism, thereby increasing the secondary productivity of primary consumers.
- B.
Increased respiratory losses (R) due to the metabolic cost of RNA synthesis decrease the plant's Net Primary Productivity (NPP), thereby reducing the energy available for secondary productivity.
- C.
The plant's NPP remains constant because RNAi is a post-transcriptional regulatory mechanism that bypasses the energy-intensive process of translation.
- D.
The excessive dsRNA acts as a supplementary respiratory substrate for primary consumers, altering their optimal foraging strategy by increasing energy transfer efficiency.
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
RNAi Vector Source|Alien Species Invasion Impacts|Niche Overlap vs. Resource Partitioning
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often compartmentalize Molecular Biology and Ecology.
The trap lies in failing to recognize that molecular synthesis (transcription of dsRNA) has a macroscopic metabolic cost (Respiration, R) that directly impacts ecological equations (NPP = GPP - R).
Option C is the primary 'Half-Truth' trap, exploiting the fact that RNAi saves translation energy, but it ignores the massive transcriptional cost of the overactive promoter.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biotechnology and Its Applications - Class 12 |
| Concept | RNAi Vector Source |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |