DNA is made up of nucleotides. Each nucleotide has three different parts, a phosphate group, deoxyribose and a base. The bases contained in DNA are Adenine, Guanine, Cytosine and Thymine. Adenine is always paired with Thymine, Cytosine is always paired with Guanine. The base pairing is what makes the DNA able to be replicated. The following are pictures of what happens during replication.