Ribonucleic acid

Ribonucleic acids (RNA) are a form of genetic material. There is much evidence, such as it's ability to self catalyse, to suggest that RNA was the first form of genetic material on earth, which is known as the RNA world hypothesis. However there has recently been some evidence that has come to light to suggest that RNA and DNA (Deoxyribonucleic Acid) appeared in a primitive form at the same time. RNA comes in many forms such as mRNA, tRNA and rRNA. It has a basic structure of the pentise sugar ribose, with a 5' phosphate group, a 2' and 3' hydroxyl group, and a 1' nucleic acid. The 2' hydroxyl group is one of the reasons for it's functional flexibility, this also means it is a less stable molecule than DNA, which is why it is not used as the main genetic molecule. 

RNA undergoes base pairing in the same way as DNA, but substitutes Thymine for Uricil.