Before You Begin
Question #47585
The Question
In a leguminous plant, the processes of water photolysis and symbiotic nitrogen fixation are spatially separated but metabolically interdependent. Which of the following statements regarding these processes and their physiological integration is INCORRECT?
Options
- A.
The Oxygen Evolving Complex (OEC) is located on the inner side of the thylakoid membrane and utilizes Mn2+ and Cl- to facilitate the light-driven splitting of water.
- B.
Nitrogenase is a Mo-Fe protein that catalyzes the reduction of N2 to NH3, requiring an energy input of 8 ATP molecules per molecule of NH3 produced.
- C.
Leghaemoglobin acts as an oxygen scavenger in the root nodules to protect the nitrogenase enzyme from the O2 evolved during localized non-cyclic photophosphorylation.
- D.
A severe deficiency of Manganese (Mn2+) directly compromises the electron supply to P680+, indirectly reducing the availability of photosynthates required to fuel nitrogen fixation.
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
Photolysis of Water Stoichiometry|Symbiotic Nitrogen Fixation|OEC (Oxygen Evolving Complex)
Why This Question Is Tricky
Common Mistakes
Location Trap & Functional Overlap: The conceptual pivot is recognizing that while leghaemoglobin scavenges O2, this O2 does NOT come from localized photolysis in the nodules.
Students often mechanically associate 'O2 production' with 'plants' and fail to spatially separate the photosynthetic source (leaves) from the nitrogen-fixing sink (underground nodules).
Additionally, it tests the quantitative nuance of ATP consumption (8 ATP per NH3 vs 16 ATP per N2).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Photosynthesis in Higher Plants - Class 11 |
| Concept | Action Spectrum vs Absorption Spectrum |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |