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Question #46977
The Question
A researcher observes that a population of Paramecium introduced into a water body with an exceptionally high Biochemical Oxygen Demand (BOD) rapidly loses its motility. What is the most accurate physiological explanation for this phenomenon?
Options
- A.
The high concentration of organic matter directly inhibits the assembly of tubulin dimers in the 9+2 axoneme.
- B.
A sharp decline in dissolved oxygen arrests oxidative phosphorylation, causing an ATP deficit that fails to sustain dynein-mediated microtubule sliding.
- C.
Increased microbial activity produces toxins that competitively inhibit the binding of calcium ions to the ciliary basal bodies.
- D.
The protozoans shift to anaerobic respiration, producing sufficient ATP but failing to maintain the proton gradient required for ciliary beating.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Undulipodia|Centrioles|Basal_Bodies
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating Ecology (BOD/DO inverse relationship) with Cell Biology (Eukaryotic ciliary ATP dependence) and Respiration (Aerobic vs Anaerobic energy yield).
The primary trap is Option D, which exploits the common misconception of confusing the proton-motive force used by prokaryotic flagella with the ATP-dependent dynein mechanism of eukaryotic cilia.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biological Classification - Class 11 |
| Concept | Protozoan Locomotory Organs |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |