Ribosomal RNA
A molecular component of a ribosome, the cell's essential protein factory. Ribosomal RNA (rRNA) fabricates polypeptides (assemblies of amino acids that make up proteins). A tiny particulate structure located in the cytoplasm of the cell (outside the nucleus), the ribosome is composed of two subunits, one larger than the other. Both subunits were believed to contain both rRNA and protein but this is not the full story. Molecular maps of the ribosome have revealed startling details about its structure that boost support for an "RNA world" as the model for the origin of life on Earth. Although the ribosome consists of both ribosomal RNA (rRNA) and protein, the "active site" on the large unit of the ribosome — the site of the chemical reaction that changes genetic information into the beginnings of a protein — contains only rRNA. This suggests that the ribosome is actually a ribozyme, an RNA molecule that can catalyze its chemical reactions. RNA's starring role in the ribosome may therefore support the idea that life on Earth began with RNA.

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ribosomal RNA n RNA that is a fundamental structural element of ribosomes called also rRNA

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(rRNA) the most abundant form of RNA; together with proteins it forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs. Individual chains are conventionally designated by their sedimentation coefficients. Eukaryotic ribosomes contain four different rRNA chains (5S, 5.8S, 18S, and 28S), synthesized in the nucleolus and constituting the bulk of the ribosome; prokaryotic ribosomes contain three (5S, 16S, and 23S).

Medical dictionary. 2011.

Look at other dictionaries:

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  • ribosomal RNA — ribosomal RNA. См. рРНК. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

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  • ribosomal RNA — ribosominė RNR statusas T sritis chemija apibrėžtis Ribonukleorūgštis, kuri susijungusi su baltymu sudaro ribosomą. santrumpa( os) rRNR atitikmenys: angl. ribosomal RNA rus. рибосомная РНК …   Chemijos terminų aiškinamasis žodynas

  • ribosomal RNA — Abbreviation: rRNA The RNA molecules that are essential structural and functional components of ribosomes, where protein synthesis occurs. Different classes of rRNA molecule are identified by their sedimentation (S) values. E. coli ribosomes… …   Glossary of Biotechnology

  • ribosomal RNA — noun Date: 1961 RNA that is a fundamental structural element of ribosomes called also rRNA …   New Collegiate Dictionary

  • ribosomal RNA — (rRNA) The RNA present in ribosomes; ribosomes contain several sizes of single stranded rRNA that contribute to ribosome structure and are also directly involved in the mechanism of protein synthesis …   Dictionary of microbiology

  • ribosomal RNA — See RNA …   Dictionary of molecular biology

  • ribosomal RNA — Biochem. a type of RNA, distinguished by its length and abundance, functioning in protein synthesis as a component of ribosomes. Abbr.: rRNA [1960 65; RIBOSOME + AL1] * * * …   Universalium

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