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Prokaryote cell showing the nucleoid.

In prokaryotes, the nucleoid (meaning nucleus-like and also known as the nuclear region, nuclear body or chromatin body) is an irregularly shaped region within the cell where the genetic material is localised. The nucleic acid is a circular, double-stranded piece of DNA and multiple copies may exist. This method of genetic storage can be contrasted against that of the eukaryotes, where DNA is packed into chromatins and sequestered within a membrane-bound organelle called the nucleus. The nucleoid can be clearly visualised on an electron micrograph at high magnification, where although its appearance may differ, it is clearly visible against the cytosol. Sometimes even strands of what is thought to be DNA are visible. By staining with the Feulgen stain, which specifically stains DNA, the nucleoid can also be seen under a light microscope. Image File history File links Please see the file description page for further information. ... It has been suggested that this article or section be merged into Nucleoid. ... == Headline texiuvvp;iyppp;iv--24. ... == Headline texiuvvp;iyppp;iv--24. ... Prokaryotes are unicellular (in rare cases, multicellular) organisms without a nucleus. ... Look up cell in Wiktionary, the free dictionary. ... Genetic material is used to store the genetic information of an organic life form. ... The structure of part of a DNA double helix Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the development and function of living organisms. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Protista Alternative Phylogeny Unikonta    Opisthokonta    Amoebozoa Bikonta    Apusozoa    Cabozoa       Rhizaria       Excavata    Corticata       Archaeplastida       Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms with a complex cell or cells, where the genetic material is organized into a membrane-bound nucleus or nuclei. ... Chromatin is the complex of DNA and protein found inside the nuclei of eukaryotic cells. ... HeLa cells stained for DNA with the Blue Hoechst dye. ... An electron micrograph is a micrograph made with an electron microscope. ... The cytosol (cf. ... Feulgen stain is a staining technique discovered by Robert Feulgen and used in histology to identify chromosomal material or DNA in cell specimens. ...

Composition

Experimental evidence suggests that the nucleoid is largely composed of DNA, about 60%, with a small amount of RNA and protein. The latter two constituents are likely to be mainly messenger RNA and the transcription factor proteins found regulating the bacterial genome. Proteins helping to maintain the supercoiled structure of the nucleic acid are known as nucleoid proteins and are distinct from the functionally similar histones present in eukaryotic nuclei. Ribonucleic acid (RNA) is a nucleic acid polymer consisting of nucleotide monomers, that acts as a messenger between DNA and ribosomes, and that is also responsible for making proteins out of amino acids. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... The life cycle of an mRNA in a eukaryotic cell. ... In molecular biology, a transcription factor is a protein that binds DNA at a specific promoter or enhancer region or site, where it regulates transcription. ... Schematic representation of the assembly of the core histones into the nucleosome. ...

See also

• Cell nucleus
• Plasmid

HeLa cells stained for DNA with the Blue Hoechst dye. ... Figure 1: Schematic drawing of a bacterium with plasmids enclosed. ...

References

• Prescott, L. (1993). Microbiology, Wm. C. Brown Publishers, ISBN 0-697-01372-3