Biology Evolution UHS 2024
PMDC Verified Question 1 of 47
According to endosymbiosis theory, flagella may have derived by the ingestion of prokaryotes similar to:
A
Spirochete
B
Amoeboid prokaryote
C
Aerobic bacterium
D
Spirillum
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Spirochete
Concept:

The endosymbiotic theory extends beyond mitochondria and chloroplasts, attempting to explain the origins of cellular motility structures.

Solution:

  • Lynn Margulis proposed that eukaryotic flagella and cilia originated from a symbiotic relationship with motile, spiral-shaped bacteria.
  • Specifically, she suggested they derived from ancient bacteria similar to modern Spirochetes, which attached to the surface of early host cells, eventually becoming the specialized motility appendages we see today.


Why other options are incorrect:

  • Aerobic bacterium: These are hypothesized to be the ancestors of mitochondria.
  • Cyanobacteria (not listed but relevant): Ancestors of chloroplasts.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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