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Question #45932
The Question
A mature C3 plant is suddenly subjected to a severe hypoxic environment, effectively removing the terminal electron acceptor of its mitochondrial electron transport chain (ETC). Which of the following statements is INCORRECT regarding the subsequent physiological cascade?
Options
- A.
The reduction of O2 to H2O at Cytochrome c oxidase ceases, collapsing the proton motive force required by F0-F1 ATP synthase.
- B.
The Krebs cycle enzymes accelerate their activity to compensate for the cellular ATP deficit via increased substrate-level phosphorylation.
- C.
The standard light compensation point dynamics are disrupted because the rate of aerobic CO2 evolution is replaced by anaerobic fermentation kinetics.
- D.
Systemic active transport processes, such as the loading of sucrose into the phloem sieve tubes, crash due to a severe deficit in cellular ATP.
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
Cytochrome_Oxidase|Oxygen|Anaerobic_Respiration
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often misunderstand the dependency of the Krebs cycle on the ETC.
While the Krebs cycle itself does not directly consume oxygen, it strictly requires the NAD+ and FAD regenerated by the ETC.
A common misconception is that substrate-level phosphorylation in the Krebs cycle can act as a compensatory backup during hypoxia, failing to realize that the entire mitochondrial matrix metabolism stalls without the terminal electron acceptor.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Respiration in Plants - Class 11 |
| Concept | Compensation Point Logic |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |