Prokaryote

Prokaryotes (from Old Greek pro- before + karyon nut, referring to the cell nucleus, + suffix -otos, pl. -otes; also spelled "procaryotes") are organisms without a cell nucleus (= karyon), or indeed any other membrane-bound organelles, in most cases unicellular (in rare cases, multicellular). This is in contrast to eukaryotes (also spelled "eucaryotes"), organisms that have cell nuclei and may be variously unicellular or multicellular. The difference between the structure of prokaryotes and eukaryotes is so great that it is considered to be the most important distinction among groups of organisms. Most prokaryotes are bacteria, and the two terms are often treated as synonyms. However, Woese has proposed dividing prokaryotes into the Bacteria and Archaea (originally Eubacteria and Archaebacteria) because of the significant genetic differences between the two. This arrangement of Eukaryote, Bacteria, and Archaea is called the three-domain system.

Related Topics:
Old Greek - Nut - Suffix - Pl. - Cell nucleus - Unicellular - Multicellular - Eukaryote - Bacteria - Woese - Archaea - Three-domain system

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