Prokaryotic cells are single-celled microorganisms. These organisms are known to be evolved earlier than anyone on earth. Prokaryote organisms include bacteria and archaebacteria. The photosynthetic prokaryotes perform photosynthesis that includes cyanobacteria. A prokaryotic cell is unimembranous and therefore, all the reactions occur within the cytoplasm. They can be free-living or parasitic organisms. The prokaryotic cell is represented by bacteria, BGA (Blue-Green Algae), PPLO (pleuropneumonia like organism)/Mycoplasma. Mycoplasma is the smallest/simplest organism capable of autonomous growth and reproduction. It has a size of 0.1 microns and reproduces mainly by binary fission or elementary bodies. Examples: Mycobacterium, Oscillatoria. Examples of cyanobacteria are Nostoc, Anabaena, etc.