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Question #46994
The Question
Members of Ascomycetes exhibit diverse modes of nutrition, including saprophytic and parasitic lifestyles. During the evolutionary transition of certain Ascomycetes from a saprophytic to an obligate parasitic mode, a significant metabolic shift occurs. Which of the following statements most accurately describes this adaptation regarding their enzymatic activity and amphibolic pathways?
Options
- A.
They upregulate the secretion of extracellular cellulases and ligninases to aggressively decompose living host tissues for energy.
- B.
They bypass extensive extracellular catabolic breakdown of complex detritus by directly absorbing host-derived carbon skeletons to feed their own amphibolic pathways.
- C.
They completely lose their mitochondrial amphibolic pathways, functioning similarly to viruses by utilizing host ribosomes for ATP synthesis.
- D.
They shift from absorptive heterotrophy to holozoic nutrition, engulfing host metabolites to maintain their intracellular carbon pool.
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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
Ascomycetes Sac Fungi|DNA vs Chromosome Content|Centromere Positionality
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the general fungal trait of 'secreting extracellular enzymes for digestion' but fail to differentiate the metabolic economy of an obligate parasite.
The trap lies in assuming all fungi rely equally on massive extracellular enzymatic digestion.
Obligate parasites minimize destructive extracellular catabolism to keep the host alive, instead acting as metabolic sinks that siphon off host carbon skeletons, representing an advanced application of the NCERT 'Amphibolic Pathway' concept.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biological Classification - Class 11 |
| Concept | Ascomycetes Sac Fungi |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |