RNA
From Memory Alpha, the free Star Trek reference.
Ribonucleic Acid (RNA) is a substance found in all living cells which acts as a controller of protein synthesis. It is similar in construction to its counterpart deoxyribonucleic acid (DNA), with the replacement of ribose for deoxyribose and the pyrimidine uracil for thymine.
Following his exposure to a quantum fissure in 2370, Worf's cellular RNA was thrown into a state of flux, which extended to the subatomic level. This was the first clue to the nature of Worf's quantum disassociation; essentially he was in the wrong quantum reality. (TNG: "Parallels")
The RNA of the Dominion's Teplan blight virus was found to be difficult to recreate, thus hindering vaccination efforts. (DS9: "Inter Arma Enim Silent Leges")
