Ribonucleic acids, abbreviated RNA, are nucleic acids built from ribose sugar, phosphate, and the nitrogenous bases adenine, guanine, cytosine, and uracil. RNA carries out protein synthesis and gene regulation in every living cell, including the fermentation microbes, crop plants, and food animals of the food system. Food scientists study RNA to understand gene expression during fermentation, to detect and identify microorganisms, and to develop molecular tools for authenticity testing and pathogen tracing. Messenger, transfer, and ribosomal forms each play distinct roles in translating genetic instructions into functional proteins.