Every living organism falls into one of two groups: eukaryotes or prokaryotes, with cellular structure determining which group an organism belongs to. Prokaryotes are unicellular and lack a nucleus ...

Bacteria are amongst the simplest of organisms – they are made of single cells. Their cell structure is simpler than the cells of animals, plants and fungi.

In addition to the nucleus, eukaryotic cells may contain several other types of organelles, which may include mitochondria, chloroplasts, the endoplasmic reticulum, the Golgi apparatus ...

The origin of eukaryotes: a reappraisal. Nat Rev Microbiol 8, 395–403 (2007) doi:10.1038/nrg2071. Dolan, M. F. & Margulis, L. Advances in biology reveal truth about prokaryotes. Nature 445 ...