Ribonucleic acid (RNA) is a nucleic acid that consists of a long chain of nucleotide units.
RNA is very similar to DNA, in the cell, RNA is usually single-stranded, while DNA is usually double-stranded; RNA nucleotides contain ribose while DNA contains deoxyribose; and RNA has the base uracil rather than thymine that is present in DNA.
A type of RNA called messenger RNA (mRNA) carries information from DNA to structures called ribosomes to translate proteins. Transfer RNA (tRNA) and ribosomal RNA (rRNA) are both involved in the process of translation.
There are RNAs with other roles – in particular regulating which genes are expressed (SiRNA), but also as the genome of most viruses.
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