Compare and contrast prokaryotic and eukaryotic cells in terms of the structural organization of their genetic material.

The major cellular feature which sets the distinction between a prokaryotic (‘pro’ – before, ‘karyon’ – kernel, nucleus) cell and a eukaryotic (‘eu’ – true, ‘karyon’ – kernel, nucleus) cell is the presence of a nucleus. In prokaryotic cells the genetic material resides in a region of the cytoplasm called the nuncleoid which is not separated from the rest of the cell by membranes and therefore a true nucleus is absent. In contrast, eukaryotes have their genetic material contained within a membrane-bound organelle known as the nucleus which allows for spatial separation of the processes of transcription and translation. The eukaryotic nucleus also contains nucleoli which are regions where ribosomes are organized but this structure is altogether lacking in prokaryotes. Another distinctive feature between prokaryotic and eukaryotic cells is that the prokaryotic DNA is not associated with histone proteins whereas the eukaryotic DNA is. Furthermore, bacterial DNA is normally found as a single circular DNA molecule and multiple and much smaller circular elements known as plasmids. In contrast, eukaryotic genetic material is in the form of a number of linear chromosomes, and plasmids are rare. Despite these structural differences, the genetic material in any cell, be it prokaryotic or eukaryotic, is in the form of deoxyribonucleic acid (DNA) and this is a universal feature of all cellular life forms.