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🔬 Biology  ·  Cell: The Unit of Life  ·  NEET

Which observation best supports the endosymbiotic origin of mitochondria?

Answer: They have 70S ribosomes and circular DNA.

  • A They are bound by a single membrane
  • B They completely lack their own DNA
  • C They have 70S ribosomes and circular DNA
  • D They are found only in plant cells

Correct answer: C. They have 70S ribosomes and circular DNA

Explanation: Mitochondria have their own circular DNA, 70S ribosomes and a double membrane - features of free-living prokaryotes, supporting an endosymbiotic origin.

Labeled diagram of an animal cell showing nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, and other organelles

Animal cell structure with major organelles labeled. Image: LadyofHats (Mariana Ruiz), Public Domain, via Wikimedia Commons.

Concept context

Cell theory, prokaryotic vs eukaryotic cells, organelles and their functions. Foundation of all biology.

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