linguistic:paraphrasing
Mitochondria

Mitochondria are organelles that synthesize the energy-carrying molecule ATP for the cell by metabolizing carbon-based macromolecules. The presence of DNA in mitochondria and proteins, derived from mtDNA, suggest that this organelle may have been a prokaryote prior to its integration into the proto- eukaryote. Mitochondria are regarded as organelles rather than endosymbionts because mitochondria and the host cells share some parts of their genome, undergo division simultaneously, and provide each other with means to produce energy. The endomembrane system and nuclear membrane were hypothesized to have derived from the protomitochondria.