DNA (Deoxyribose Nucleic Acid) is a macromolecule made up of nucleotides which consist of nitrogenous base (adenine, cytosine, guanine and thymine) pentose sugar (deoxyribose sugar) and phosphate. Types of carbohydrate are as follows In DNA molecule two antiparallel polydeoxyri-bonucleoride strands held together by hydrogen bonds. Adenine base forms two hydrogen bonds with thymine and guanine forms three hydrogen bonds with cytosine. Whereas in RNA thymine base replaced by uracil base.