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Bacteria (singular bacterium)

When used as the meaning of “eubacteria”, bacteria is a group of single cell organisms that do not have a distinct nuclear membrane and that have linear carbohydrate chains as the major component of the hydrophobic tail of membrane lipids. Eubacteria constitute a domain of life.

Eubacteria and archea (archenobacteria) together constitute prokaryotes. Archaea do not have distinct nuclear membrane, but their membrane lipids mainly contain isoprenoids. Archea also constitute a domain of life.

The term “bacteria” is sometimes used to represent prokaryotes. This is because the group “archea” was identified relatively recently. Before the identification of archea, bacteria were the only prokaryotic organisms.


Definitions in the literature

  • A diverse group of ubiquitous microorganisms all of which consist of only a single cell that lacks a distinct nuclear membrane and has a cell wall of a unique composition [1].
  • one of life's three domains; consists of prokaryotes that are only distantly related to members of the domain Archaea [2].
  • The most diverse and well-known group of prokaryotes (organisms that lack a nucleous) [3].