Transfer ribonucleic acid (tRNA), artwork. The main image shows the four-pronged shape of the type of RNA known as transfer RNA (tRNA), with nucleic acid strands radiating outwards in the background. In both cases, the nucleic acid backbone is the solid line, and the small coloured blocks are the four RNA nucleotide bases: adenine (A), cytosine (C), guanine (G), and uracil (U). RNA is a biological molecule that plays a vital role in producing proteins from genes, with tRNA playing the vital role in 'translation', the first stage of this process. tRNA consists of 74 to 95 nucleotides.