Prokaryotes have no cell nucleus and no membrane enclosed organelles. Prokaryotic DNA can be found in a coiled loop floating in the cytoplasm in a region called the nucleoid (meaning nucleus-like). In other words, the nucleoid is the area in a prokaryotic cell where DNA is located.
In eukaryotic cells, DNA is located in the nucleus, the mitochondria and the chloroplasts (occuring only in plants and some protists). The nucleus contains most DNA. It is present in this compartment in the form of linear chromosomes that together constitute the genome.
