Which feature of mitochondria supports the view that they arose from free living prokaryotes?

  • A. They are bounded by a single membrane
  • B. They contain digestive enzymes like a lysosome
  • C. They carry 80S ribosomes identical to those of the cytoplasm
  • D. They contain circular DNA and 70S ribosomes and divide by binary fission

Explanation

Circular DNA, 70S ribosomes and division by fission are all bacterial characteristics, and they are exactly what the endosymbiotic theory predicts for an organelle descended from an engulfed prokaryote. A mitochondrion has two membranes, not one, the outer one being the vesicle the host cell wrapped it in. Its ribosomes are 70S, so the presence of 80S ribosomes would argue against the theory rather than for it.

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