one of the three main macromolecules of living organisms (along with DNA and proteins), which plays a key role in the coding, reading, regulation, and expression of genes. Types of RNA and their functions: messenger RNA (mRNA) – transfers genetic information from DNA to ribosomes; transfer RNA (tRNA) – delivers amino acids to the site of protein synthesis; ribosomal RNA (rRNA) – forms the structural basis of ribosomes; small nuclear RNAs – participate in mRNA processing; regulatory RNAs control the work of genes.