An aggregation of DNA found in prokaryotes and in the mitochondria and chloroblasts of eukaryotes, and which has some resemblance to a nucleus, but lacks a nuclear envelope and histones. A chloroblast is the place in a cell where photosynthesis takes place.
See DNA (deoxyribonucleic acid), Eukaryote cell (or organism), Histone, Mitochondria, Nucleus (of a cell), Prokaryote cell (or organism)