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Question #47605
The Question
Consider a C3 plant subjected to a sudden environmental temperature shift from 25°C to 35°C on a bright sunny day. Which of the following statements regarding the resulting metabolic shift is INCORRECT?
Options
- A.
The specificity factor of RuBisCO for CO2 decreases, and the stromal O2/CO2 ratio increases due to the differential decrease in gas solubility.
- B.
RuBP is oxygenated in the chloroplast to yield one molecule of 3-phosphoglycerate and one molecule of 2-phosphoglycolate.
- C.
The C2 cycle acts as a perfect salvage pathway, completely recycling the carbon from phosphoglycolate back into 3-phosphoglycerate at the expense of ATP.
- D.
The pathway creates a metabolic sink that consumes ATP and releases CO2 in the mitochondrion without the synthesis of sugars or NADPH.
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
Rubisco|Glycolate_Pathway|Peroxisome
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often recognize photorespiration as a 'salvage pathway' but fail to grasp the quantitative nuance of its inefficiency.
The trap relies on the misconception that the C2 cycle recovers 100% of the carbon lost to oxygenation.
In reality, the conversion of two glycine molecules to one serine in the mitochondrion results in an obligatory loss of 25% of the carbon as CO2, which directly contradicts the idea of 'complete recycling'.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Photosynthesis in Higher Plants - Class 11 |
| Concept | Rubisco Dual Functionality |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |