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Question #47499
The Question
In the symbiotic association of a lichen, the mycobiont must efficiently acquire photosynthates from the phycobiont. Unlike a solitary saprophytic fungus that secretes destructive exoenzymes to digest dead organic matter, the mycobiont must maintain the viability of its partner. Which of the following best explains the physiological adaptation of the mycobiont's cell wall at the symbiotic interface?
Options
- A.
It completely dissolves its chitinous cell wall to form a naked protoplast, allowing direct phagocytosis of algal nutrients.
- B.
It undergoes localized remodeling of its chitin-glucan complex to form specialized absorptive structures (haustoria) without triggering a necrotrophic response.
- C.
It replaces its N-acetylglucosamine polymers with a cellulosic wall to mimic the photobiont and evade its immune recognition.
- D.
It heavily lignifies its cell wall at the interface to prevent the leakage of absorbed nutrients back into the photobiont.
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
Lichen Symbiosis|Photosynthesis|Air Quality Bio-indicators
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the NCERT fact that fungal walls are made of chitin, but view it as a static, rigid box.
The trap is assuming the wall must be completely removed (Option A) or chemically replaced with plant-like materials (Option C) for nutrient exchange to occur.
The correct application requires understanding the 'dynamic plasticity' of the cell wall—localized remodeling to form haustoria, which balances structural integrity with symbiotic nutrient flux.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biological Classification - Class 11 |
| Concept | Lichen Symbiotic Logic |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |