The information stored in the order of bases is organized into genes: each gene contains information for making a functional product. The genetic information is first copied to another nucleic acid polymer, RNA (ribonucleic acid), preserving the order of the nucleotide bases. Genes that contain instructions for making proteins are converted to messenger RNA (mRNA). Some specialized genes contain instructions for making functional RNA molecules that don’t make proteins. These RNA molecules function by affecting cellular processes directly; for example some of these RNA molecules regulate the expression of mRNA. Other genes produce RNA molecules that are required for protein synthesis, transfer RNA (tRNA), and ribosomal RNA (rRNA).
