<Tr> <Th> Membranes </Th> <Td> cell membrane </Td> <Td> Cell membrane and membrane - bound organelles </Td> </Tr> <P> Cells are of two types, eukaryotic, which contain a nucleus, and prokaryotic, which do not . Prokaryotes are single - celled organisms, while eukaryotes can be either single - celled or multicellular . </P> <P> Prokaryotic cells were the first form of life on Earth, characterised by having vital biological processes including cell signaling and being self - sustaining . They are simpler and smaller than eukaryotic cells, and lack membrane - bound organelles such as the nucleus . Prokaryotes include two of the domains of life, bacteria and archaea . The DNA of a prokaryotic cell consists of a single chromosome that is in direct contact with the cytoplasm . The nuclear region in the cytoplasm is called the nucleoid . Most prokaryotes are the smallest of all organisms ranging from 0.5 to 2.0 μm in diameter . </P> <P> A prokaryotic cell has three architectural regions: </P>

What type of bacteria preceded the eukaryotic cell