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messenger RNA (mRNA) see ribonucleic acid.
ribosomal RNA (rRNA) see ribonucleic acid.
transfer RNA (tRNA) see ribonucleic acid.
complementary RNA (cRNA) viral RNA that is transcribed from negative-sense RNA and serves as a template for protein synthesis.
heterogeneous nuclear RNA (hnRNA) a diverse group of long primary transcripts formed in the eukaryotic nucleus, many of which will be processed to mRNA molecules by splicing.
messenger RNA (mRNA) RNA molecules, usually 400 to 10,000 bases long, that serve as templates for protein synthesis (translation).
negative-sense RNA viral RNA with a base sequence complementary to that of mRNA; during replication it serves as a template for the transcription of viral complementary RNA.
positive-sense RNA viral RNA with the same base sequence as mRNA; during replication it functions as mRNA, serving as a template for protein synthesis.
ribosomal RNA (rRNA) that which together with proteins forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs.
small nuclear RNA (snRNA) a class of eukaryotic small RNA molecules found in the nucleus, usually as ribonucleoproteins, and apparently involved in processing heterogeneous nuclear RNA.
A nucleic acid present in all living cells and many viruses, consisting of a long, usually single-stranded chain of alternating phosphate and ribose units, with one of the bases adenine, guanine, cytosine, or uracil bonded to each ribose molecule. RNA molecules are involved in protein synthesis and sometimes in the transmission of genetic information. Also called ribonucleic acid.
abbreviation for ribonucleic acid.
RNARibonucleic acid Molecular biology A polymer of ribonucleic acids that functions in coding, storage, transfer and translation of genetic information. See Antisense RNA, Catalytic RNA, Chromosomal RNA, Heterogenous nuclear RNA, Pre-mRNA, Ribosomal RNA, Transfer RNA.
Abbreviation for ribonucleic acid.
RNAAbbrev. for ribonucleic acid. This molecule, in common with DNA and MITOCHONDRIAL DNA, carries coded instructions for the synthesis of specific proteins from AMINO ACIDS. RNA may be a double chain like DNA but in the cell usually exists as a single polynucleotide chain, like one strand of the double helix of DNA. Whereas in most cells DNA carries the permanent, inheritable code for cell reproduction, RNA most commonly acts as a transcriber or as MESSENGER RNA (mRNA) carrying the code elsewhere, as to the RIBOSOMES in cells where proteins are actually formed. In some viruses, however, the inherited code for replication occurs in the form of RNA. Transfer RNA (tRNA) picks up and carries amino acids to the ribosomes to be inserted in the correct sequence of the protein. Ribosomes contain ribosomal RNA (rRNA) and proteins.RNA can take up complex three-dimensional configurations an can act as an enzyme with itself as substrate. It seems likely that RNA preceded DNA in evolution.
RNA (ribonucleic acid)a NUCLEIC ACID generally composed of a single POLYNUCLEOTIDE CHAIN of RIBONUCLEOTIDES,which is found in cells of both prokaryotes and eukaryotes. RNA is a vital component of PROTEIN SYNTHESIS, and occurs in three main forms:
- (a) MESSENGER RNA produced in TRANSCRIPTION and involved in transferring genetic information from DNA to RIBOSOMES;
- (b) RIBOSOMAL RNA forming a major structural component of the ribosomes;
- (c) TRANSFER RNA which acts as an ‘adaptor’ molecule and carries amino acids to the ribosomes to be inserted in the correct sequence during translation. RNA is also found in some viruses as the primary genetic material. Other types of RNA have regulatory roles; see, for example, ANTISENSE RNA; or processing roles, for example snRNA.
Abbreviation for ribonucleic acid.
RNA interference (RNAi)
the functional inactivation of specific genes by experimental introduction of a corresponding double stranded RNA, which induces degradation of the complementary single-stranded mRNA encoded by the gene but not that of mRNAs with different sequences. See microRNA and gene silencing.
small RNAs containing 21 to 33 nucleotides that associated with multiple proteins in a RNA-induced silencing complex (RISC) that repress transcription of specific target mRNA by hybridizing to its 3' untranslated region.
a sequence of about 10 nucleotides long copied from DNA by RNA primase and required for the priming of the synthesis of each Okazaki fragment during DNA replication.
secondary structure RNA
folding of single-stranded RNA molecules which arises from intramolecular base pairing.
small cytoplasmic RNA (scRNA)
small (7S; 129 nucleotides) RNA molecules found in the cytosol and rough endoplasmic reticulum associated with proteins that are involved in specific selection and transport of other proteins.
small nuclear RNA (snRNA)
a general term for many diferent kinds of small RNA molecules found in the nucleus of a cell that include as examples species involved in splicing of introns from mRNA and in RNA interference.
viruses distinguished by having a ribonucleic acid genome, usually as a single strand which may be positive or negative sense, a single molecule or a segmented; in at least two families the genome is a double-strand segmented form.