The deoxyribonucleic acid (DNA) is the basic functional unit of a living system that provides the essential information to be transferred in the form of a protein. The DNA is composed of four nitrogenous bases, deoxy ribose sugar, and phosphate molecules. In a double stranded DNA molecule, each of these strands was held complementary to each other with the help of hydrogen bonds. Covalent bonds are also involved in a DNA double helix in each of the linear strand, which strongly binds the bases, sugars, and phosphate groups within and between the components.