The lack of the nuclear envelope and membranaeous organelles is characteristic of prokaryotes. In bacteria such as a E. coli, the genetic material is present as a long, circular DNA molecule that is compacted into an area referred as the nucleotid area. Part of the DNA may be attached to the cell membrane, but in general the nucleotid cinstitutes a larhe area trougout the cell. Although the DNA is compacted, it does not undergo the extensive coiling characteristic of the stages of mitosis were, in eukaryotes, chromosome become visible. Nor is the DNA in these organism associated as extensively with proteins as is eukaryotic DNA. Prokaryotic cells do not have a distinct nucleolus, but do contain genes that specify rRNA molecules.