prokaryote

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Related to procaryote: eucaryote

prokaryote:

see MoneraMonera,
taxonomic kingdom that comprises the prokaryotes (bacteria and cyanobacteria). Prokaryotes are single-celled organisms that lack a membrane-bound nucleus and usually lack membrane-bound organelles (mitochondria, chloroplasts; see cell, in biology).
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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Prokaryote

 

an organism that does not have a typical cell nucleus and chromosomal apparatus. Prokaryotes include bacteria, blue-green algae, rickettsiae, and mycoplasms.

In the organic world, according to the latest classification system, prokaryotes are classified as a kingdom (Prokariota) or a superkingdom that is comparable to the kingdom or super-kingdom of eukaryotes. In prokaryotes, the physical substrate associated with the transmission and realization of hereditary information consists of a strand of deoxyribonucleic acid (DNA). The DNA usually has a ringlike shape and is localized more or less in the central part of the organism, which is called the nucleoid; the nucleoid is not separated by a membrane from the cytoplasm. Unlike the DNA in eukaryotes, the DNA in prokaryotes is usually not bound to histones (it does not form nucleohistone) and the functioning of genes is regulated through metabolites. Also, prokaryotes do not have mitochondria and complexly organized flagella.

Prokaryotes play a very important role in the cycle of matter in the biosphere. Blue-green algae were probably the first autotrophic organisms to appear on earth in the course of the evolution of life.

REFERENCE

Peshkov, M. A. Tsitologiia bakterii. Moscow-Leningrad, 1955.

IU. I. POLIANSKII

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

prokaryote

[prō′kar·ē‚ōt]
(cell and molecular biology)
A primitive nucleus, where the deoxyribonucleic acid-containing region lacks a limiting membrane.
Any cell containing such a nucleus, such as the bacteria and the blue-green algae.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Like the transgenic procaryotes that preceded them in the repertoire of scientific investigative tools, transgenic eucaryotes will ultimately provide humankind with fundamental and valuable knowledge of the natural world.
The rRNA clock makes it clear, Pace says, that the eukaryotes, animals whose cells have nuclei -- have as ancient an origin as procaryotes, organisms whose cells have no nucleus (SN:5/3/86,p.280).
The species concepts for procaryotes. FEMS Microbiology Review, 2001; 25: 39-67.
Stackebrandt, 2006.The Procaryotes,In: The Genera Staphylococcus and Macrococcus, Library of congres, 4: 5-75.
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Etudes des microhabitats contenus dans les agregats du sol, leur relation avec la biomasse bacterienne et la taille des procaryotes presents.
Mycoplasmas may be the only procaryotes which can symbiotically grow in the eucaryotic host and have a close interaction with mammalian cells for long periods.