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Question #45770
The Question
Both Escherichia coli and human spermatozoa utilize flagella for locomotion. Which of the following statements accurately describes the evolutionary relationship and the underlying structural mechanics of these two organelles?
Options
- A.
They are analogous structures; the bacterial flagellum is composed of flagellin and operates as a rotary motor, while the sperm flagellum has a 9+2 microtubular core driven by ATP-hydrolyzing dynein.
- B.
They are homologous structures indicating divergent evolution; both originate from a basal body but differ in that only the sperm flagellum possesses a 9+2 arrangement of tubulin.
- C.
They are analogous structures representing convergent evolution; both achieve motility through the ATP-dependent sliding of tubulin doublets, despite differing in overall length.
- D.
They are homologous structures; the bacterial flagellum utilizes a proton motive force whereas the sperm flagellum utilizes ATP, though both share a highly conserved tubulin-based axoneme.
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
Prokaryotic_Flagella|Eukaryotic_Cilia|Flagellin_vs_Tubulin
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often assume that organelles sharing the exact same name ('flagella') across different domains of life must be homologous.
The trap lies in failing to distinguish between the flagellin-based rotary motor of prokaryotes and the tubulin-based (9+2) ATP-driven sliding mechanism of eukaryotes, which is a classic example of functional analogy (convergent evolution) rather than structural homology.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Locomotion and Movement - Class 11 |
| Concept | Ciliary/Flagellar Ultrastructure |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |