[Campbell Biology P.158] According to the endosymbiont theory and supporting evidence mentio... | Practice Question

According to the endosymbiont theory and supporting evidence mentioned in the text, which structural feature of mitochondria and chloroplasts distinguishes them from organelles of the endomembrane system and provides strong support for their prokaryotic origin?

  • A: Their ability to synthesize ATP.
  • B: Their possession of an internal system of membranous sacs.
  • C: Their presence within eukaryotic cells.
  • D: Their being surrounded by two membranes.

Explanation

The text states: "First, rather than being bounded by a single membrane like organelles of the endomembrane system, mitochondria and typical chloroplasts have two membranes surrounding them. Chloroplasts also have an internal system of membranous sacs. There is evidence that the ancestral engulfed prokaryotes had two outer membranes, which became the double membrane." This directly supports their endosymbiotic origin.