Bacteria are prokaryotic cells; fungi, protozoa, algae, plants, and animals are composed of eukaryotic cells. 7. Viruses are not cells so they are neither prokaryotic nor eukaryotic. They can replicate only inside a living cell.ccording to the cell theory, t he cell is the basic unit of life. All living organisms are composed of one or more cells. Based on the organization of their cellular structures, all living cells can be divided into two groups: prokaryotic and eukaryotic (also spelled procaryotic and eucaryotic).