RNA stands for ribonucleic acid. Unlike DNA which is double-stranded in nature, RNA is a single strand of nucleotides. It is a key metabolic process for all steps of protein synthesis in all living cells. RNA is present as a carrier of genetic information in many viruses. It occurs in a variety of lengths and shapes. Different types of RNA are found in nature that is messenger RNA (mRNA), ribosomal RNA (rRNA) and tRNA(transfer RNA)