DNA Structure and Function
Subject:
Biology [1]
Lecture Notes DNA, Genes, Chromosomes and Genetic Testing DNA structure DNA is a double-stranded helical structure. The basic building block of DNA is the nucleotide (base + phosphate + sugar). The backbone of each strand of the helix consists of a sugar-phosphate polymer. In DNA, the sugar is deoxyribose and the phosphates are attached through ester bonds to its 3' to 5' hydroxyl group (i.e. phosphodiester bonds are formed between adjacent deoxyribose units). At the 1' position of the sugar ring is one of 4 nitrogen-containing bases. Two of these, Adenine and Guanine are purines and the other two, Cytosine and Thymine are pyrimidines.