RNA, ribosomal
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.

Medical dictionary. 2011.

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  • RNA — [är΄en΄ā′] n. a nucleic acid that is an essential component of all cells, composed of a long, usually single stranded chain of nucleotide units that contain the sugar ribose; ribonucleic acid: see MESSENGER RNA, TRANSFER RNA, RIBOSOMAL RNA …   English World dictionary

  • RNA — For other uses, see RNA (disambiguation). A hairpin loop from a pre mRNA. Highlighted are the nucleobases (green) and the ribose phosphate backbone (blue). Ribonucleic acid (English pronunciation: /raɪbɵ.njuːˌkleɪ.ɨk ˈæsɪd/), or RNA, is one of… …   Wikipedia

  • 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… …   Medical dictionary

  • RNA — Genetics. ribonucleic acid: any of a class of single stranded molecules transcribed from DNA in the cell nucleus or in the mitochondrion or chloroplast, containing along the strand a linear sequence of nucleotide bases that is complementary to… …   Universalium

  • RNA — Short for ribonucleic acid, a nucleic acid molecule similar to DNA but containing ribose rather than deoxyribose. RNA is formed upon a DNA template. There are several classes of RNA molecules. They play crucial roles in protein synthesis and… …   Medical dictionary

  • RNA — noun Etymology: ribonucleic acid Date: 1948 any of various nucleic acids that contain ribose and uracil as structural components and are associated with the control of cellular chemical activities compare messenger RNA, ribosomal RNA, transfer… …   New Collegiate Dictionary

  • RNA — biochem. gen ribonucleic acid: any of a class of single stranded nucleic acid molecules of ribose and uracil, found chiefly in the cytoplasm of cells and in certain viruses; important in protein synthesis and in the transmission of genetic… …   From formal English to slang

  • Ribosomal RNA — (rRNA) is the central component of the ribosome, the protein manufacturing machinery of all living cells. The function of the rRNA is to provide a mechanism for decoding mRNA into amino acids and to interact with the tRNAs during translation by… …   Wikipedia

  • Ribosomal protein S19 — Ribosomal protein S19, also known as RPS19, is a human gene.cite web | title = Entrez Gene: RPS19 ribosomal protein S19| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene Cmd=ShowDetailView TermToSearch=6223| accessdate = ] PBB Summary… …   Wikipedia

  • ribosomal RNA — n. a form of RNA that is one of the constituent elements of ribosomes and is associated with messenger RNA and transfer RNA in the synthesis of proteins …   English World dictionary

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