Prokaryotic cells lack a nucleus. Organisms classified as prokaryotes include bacteria and archaea. They are single-celled and perform all cellular activity in their cytoplasm without specialized organelles.
The genetic material of prokaryotes resides in an open area of the cytoplasm called the nucleoid. The DNA molecule is one double-helix structure that forms into a coil. Prokaryotes perform binary fission, a type of asexual reproduction. The single DNA strand replicates, and each strand moves to opposite ends of the cell. The cellular membrane between the two copies of DNA grows until the cell is twice its original size. Finally, the membrane pinches in between the strands, forming a cell wall. The identical sections separate into two new daughter cells.