RNA (ribonucleic acid) plays a critical role in biology because it is involved in gene expression, protein synthesis, and regulation of cellular processes. It serves as a messenger (mRNA) of genetic information from DNA to ribosomes for protein synthesis. Transfer RNA (tRNA) facilitates the assembly of amino acids into proteins, while ribosomal RNA (rRNA) constitutes an integral part of ribosomes. Small RNAs also control gene expression, influencing cell function and development.
Aside from cellular processes, RNA is also the genetic material of viruses such as retroviruses like HIV. RNA molecules like microRNA and siRNA are key regulators of genes through the regulation of translation and mRNA degradation. The catalysis of biochemical reactions by RNA (ribozymes) indicates that early life forms might have been based on RNA systems. With advances in biotechnology, RNA-based therapeutics like mRNA vaccines have changed the face of medicine. These varied roles render RNA essential in biology, impacting genetics, evolution, and contemporary science.