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Question #46959
The Question
A marine biologist observes a population of diatoms (Chrysophytes) exposed to abnormally high environmental silicate concentrations, leading to the formation of hyper-thickened silica cell walls. During a subsequent prolonged dark phase, the population suffers a rapid metabolic crash despite possessing abundant stored lipids. Which of the following best explains the primary physiological bottleneck responsible for this systemic failure?
Options
- A.
The thickened frustule restricts gaseous exchange, depriving the mitochondrial inner membrane of the terminal electron acceptor needed to drive ATP synthesis.
- B.
The silica barrier prevents the efflux of photosynthetically generated O2, causing severe photo-oxidative damage to the cellular machinery.
- C.
The hyper-thickened wall blocks the absorption of photosynthetically active radiation (PAR), directly inhibiting cyclic photophosphorylation.
- D.
The structural rigidity prevents the active transport of external organic substrates required to sustain metabolism when the Calvin cycle halts.
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
Chrysophytes Silica Wall|Prokaryotic Mesosome Geometry|Cell Cycle
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often pigeonhole Diatoms strictly as 'chief producers' (photosynthesis) and forget that they possess mitochondria and absolutely require O2 for aerobic respiration during dark phases.
The trap tests the ability to link a structural boundary layer (silica frustule) to gas diffusion kinetics and the biochemical requirement of a terminal electron acceptor in the mitochondrial inner membrane.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biological Classification - Class 11 |
| Concept | Chrysophytes Silica Wall |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |