A critical feature of DNA is the ability of the nucleotides to make specific pairs: . Adenine pairs with Thymine and Cytosine pairs with Guanine. The human genome of Homo sapiens is stored on 23 chromosome pairs. 22 of these are autosomal chromosome pairs, while the remaining pair is sex-determining. The haploid human genome occupies a total of just over 3 billion DNA base pairs that means 6 billion base pairs per diploid cell.