Answer
The plastids are of prokaryotic origin and contain prokaryotic DNA.
Work Step by Step
Protists of the phylum Apicomplexa cause malaria and contribute to infections associated with AIDS. These parasites are unusual because they contain plastids. Chloroplasts are a type of plastid. The plastids and their enzymes are necessary for the survival of the parasites, so inhibition of enzymes produced by the plastids is lethal. The antibiotic that inhibits the prokaryotic enzymes kills the parasite by acting against the plastids of the parasite. This shows that the plastids are of prokaryotic origin and contain prokaryotic DNA. The DNA code for prokaryotic enzymes, due to this its enzymes can be inhibited by the antibiotic, which is used against prokaryotic enzymes. The parasites probably obtained the plastids by endosymbiosis of independent prokaryote, in the same way, that eukaryotes have acquired mitochondria. Some current evidence suggests that parasites obtained the plastids via secondary endosymbiosis, which means ingestion of a eukaryote that already carried the plastid by endosymbiosis of independent prokaryote.
