Before You Begin
Question #46587
The Question
Methanogens (Domain Archaea) thrive in extreme anaerobic niches due to unique features like a distinct cell wall and specialized cofactors (e.g., Coenzyme M) for methanogenesis. Occasionally, horizontal gene transfer (HGT) introduces standard bacterial metabolic genes into their genome. However, these methanogens often experience a sharp decline in their 'extremophile' fitness. What is the most accurate physiological explanation for this evolutionary trade-off?
Options
- A.
The archaeal translation machinery cannot decode bacterial mRNA due to the lack of genetic code degeneracy across domains.
- B.
The expression of non-specialized bacterial proteins imposes a severe metabolic load, disrupting the tightly regulated, cofactor-specific methanogenesis pathway.
- C.
The acquired bacterial genes automatically trigger the synthesis of a peptidoglycan cell wall, replacing the protective pseudomurein layer.
- D.
Bacterial metabolic enzymes require oxygen, which directly oxidizes and destroys the methanogen's pseudomurein cell wall.
Check Your Answer
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
Methanogens|Horizontal_Gene_Transfer|Metabolic_Adaptation
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often confuse the 'universality' of the genetic code with 'evolutionary fitness'.
A common misconception is that Archaea cannot express bacterial genes at all due to domain differences (Option A trap).
The true NCERT-Plus application requires understanding that while expression does occur, the 'cost' of expressing unoptimized, non-specialized proteins in extreme environments creates a metabolic burden that reduces evolutionary fitness.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Microbes in Human Welfare - Class 12 |
| Concept | Methanogens Metabolism |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |