DNA Structure and Replication

Deoxyribonucleic acid (DNA) is the molecule that stores the hereditary information of nearly every living organism. Its elegant structure explains both how genetic information is encoded and how it can be copied with remarkable accuracy from one generation to the next.

The Building Blocks of DNA

DNA is a polymer built from repeating units called nucleotides. Each nucleotide has three parts: a five-carbon sugar (deoxyribose), a phosphate group, and one of four nitrogenous bases. The bases are adenine (A), thymine (T), cytosine (C), and guanine (G). Adenine and guanine are double-ringed purines, while thymine and cytosine are single-ringed pyrimidines.

Nucleotides link together when the phosphate group of one attaches to the sugar of the next, forming a sugar-phosphate backbone through coval