Cellular life

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Cellular life is life with cells. The usual meaning of life as we know it expects that an organism have either unicellular or multicellular structure.

But implied by the modifier "cellular" is the existence of earth-based life that is non-cellular. This point of view usually includes the classification of viruses as lifeforms.

In discussing the domains of life, the term Cytota is occasionally used as a kingdom, domain, or empire name to distinguish cell-based life from the non-cellular life (labelled Acytota). Both would be the only two subdivisions of earthly life -- also known as terrestrial organisms, Biota, Naturae, or Vitae.

The issue of life being both cellular and non-cellular has recently come to the fore due to the 2003 discovery that the Mimivirus is very large, had genes for hundreds of proteins and can make some proteins that are involved in the synthesis of other proteins. This finding has suggested to some virologists and bacteriologists that there should be a fourth -- that is, viral -- domain of life, in addition to the cellular domains of Archaea, Bacteria, and Eukaryota.

[edit] See also

• Alternative biochemistry