Before You Begin
Question #46753
The Question
During the light-dependent reactions of photosynthesis, the continuous efflux of protons from the thylakoid lumen via the CF0-CF1 ATP synthase complex is crucial. If a specific inhibitor completely blocks the CF0 transmembrane channel, which of the following represents the most accurate sequence of physiological consequences, drawing a functional parallel to enzymatic failure in severe systemic acidosis?
Options
- A.
Extreme lumenal acidification -> Inhibition of the Oxygen Evolving Complex (OEC) -> Failure to reduce P680+ -> Complete cessation of the Z-scheme.
- B.
Extreme stromal acidification -> Denaturation of NADP reductase -> Accumulation of reduced ferredoxin -> Obligate shift to cyclic photophosphorylation.
- C.
Immediate collapse of the proton gradient -> Inability of Plastoquinone to pump protons -> Over-reduction of Cytochrome b6f -> Halting of water photolysis.
- D.
Hyper-alkalinization of the thylakoid lumen -> Dissociation of the Manganese cluster in the OEC -> Stalling of Photosystem II -> Cessation of oxygen evolution.
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
Thylakoid Lumen Sequestration|Haldane Effect|Carbonic Anhydrase
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize that a proton gradient is 'required' for ATP synthesis, but fail to realize that an 'un-dissipated' gradient (failure of proton efflux) creates a toxic acidic environment.
This question tests the exact anatomical location of the OEC (lumenal side) and the dual consequence of chemiosmosis: ATP production and pH homeostasis.
It uses the 'Location Trap' (Stroma vs Lumen) and 'Directional Trap' (Acidification vs Alkalinization) to filter out rote memorization.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Cell – The Unit of Life - Class 11 |
| Concept | Thylakoid Lumen Sequestration |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |