Ribonucleic acid or RNA is one of the three major biological macromolecules that are essential for all known forms of life (along with DNA and proteins). A central tenet of molecular biology states that the flow of genetic information in a cell is from DNA through RNA to proteins: “DNA makes RNA makes protein.” Proteins are the workhorses of the cell; they play leading roles in the cell as enzymes, as structural components, and in cell signalling, to name just a few.

DNA(deoxyribonucleic acid) is considered the “blueprint” of the cell; it carries all of the genetic information required for the cell to grow, to take in nutrients, and to propagate. RNA–in this role–is the “DNA photocopy” of the cell. When the cell needs to produce a certain protein, it activates the protein’s gene–the portion of DNA that codes for that protein–and produces multiple copies of that piece of DNA in the form of messenger RNA, or mRNA.

The multiple copies of mRNA are then used to translate the genetic code into protein through the action of the cell’s protein manufacturing machinery, the ribosomes. Thus, RNA expands the quantity of a given protein that can be made at one time from one given gene, and it provides an important control point for regulating when and how much protein gets made.