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Definition

noun

A nucleic acid that is generally single stranded (double stranded in some viruses and siRNA), composed of repeating nucleotide units of ribose sugar, phosphate group, and nitrogenous base.

Supplement

Structure: Ribonucleic acid (RNA) is a molecule consisting of a long linear chain of nucleotides. Each nucleotide unit is comprised of a sugar, phosphate group and a nitrogenous base. It differs from a DNA molecule in a way that the sugar backbone is a ribose (deoxyribose in DNA) and the bases are adenine, guanine, cytosine and uracil (thymine in DNA).

Location: In eukaryotes, it is found in the nucleus and in the cytoplasm

Function: In some viruses, RNA is the genetic material. For most organisms, RNAs are involved in:

• protein synthesis (e.g. mRNA, tRNA, rRNA, etc.)
• post-transcriptional modification or DNA replication (e.g. snRNA, snoRNA, etc.)
• gene regulation (e.g. miRNA, siRNA, tasiRNA, etc.)

Abbreviation: RNA

Compare: deoxyribonucleic acid

See also: nucleic acid