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Question #46752
The Question
An experimental plant is treated with a chemical uncoupling agent that makes the thylakoid membrane freely permeable to protons. Which of the following represents the most accurate sequence of physiological consequences?
Options
- A.
Immediate cessation of ATP synthesis, temporary continuation of NADP+ reduction, followed by oxidative stress due to Calvin cycle failure.
- B.
Immediate halt of the Z-scheme electron transport, cessation of oxygen evolution, and rapid depletion of cellular NADP+.
- C.
Accumulation of protons in the stroma leading to stromal acidification, immediate cessation of RuBisCO activity, and continuous ATP synthesis.
- D.
Uninterrupted ATP synthesis via cyclic photophosphorylation, but complete inhibition of non-cyclic photophosphorylation and NADPH production.
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
Thylakoid Lumen Sequestration|Z-Scheme|DNP(Dinitrophenol)
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between Electron Transport and Proton Motive Force.
A common misconception is that inhibiting ATP synthesis directly and immediately stops the Z-scheme.
Students must realize that uncoupling agents decouple electron flow from phosphorylation, allowing electron transport and NADPH production to continue until the Calvin cycle stalls due to ATP depletion, which subsequently halts NADP+ regeneration.
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 |