The Full form of RNA is Ribonucleic Acid. RNA is one of the major biological macromolecules that is essential for all living beings or known forms of life. RNA performs various important biological roles related to protein synthesis such as decoding, transcription, regulation and expression of genes. It is a single-stranded molecule composed of Ribonucleotides. Like DNA, It has three components: a Nitrogenous Base: It can be adenine (A), guanine (G), cytosine (C) or uracil (U), a Five-Carbon Sugar: It is ribose and a Phosphate Group: It is attached to the third position of one ribose and fifth position of the next ribose. The nucleotides of Ribonucleic Acid are joined to one another through covalent bonds that exist between the phosphate of one molecule and sugar of another molecule. This linkage between nucleotides is called bond or phosphodiester linkage. RNA is not always linear; it can fold to form a complex three-dimensional structure called hairpin loops. In this structure, nitrogenous bases bind to one another, i.e. Adenine pairs with uracil (A-U) and guanine pairs with cytosine (G-C). Hairpin loops are commonly found in messenger (mRNA) and transfer RNA (tRNA).