Base pairing of the DNA
Illustration of the structure of DNA (desoxyribonucleic acid). Its sequence of base pairings encodes our genetic information. The DNA consists of nucleotides, which again consist of a sugar (ribose), a base, and a phosphate. The bases are called adenine, guanine, cytosine, and thymine. As shown here, adenine and thymine pair with two hydrogen bridge bonds, cytosine and guanine with three.