The mechanisms that make life possible depend on the structure of the double-strand DNA molecule. Here we provide only an overview of its structure and means of reproduction. Each monomer in a single DNA strand—that is, each nucleotide—consists of two parts: a sugar (deoxyribose) with a phosphate group attached to it, and a base, which may be either adenine (A), guanine (G), cytosine (C), or thymine (T). Each sugar is linked to the next via the phosphate group, creating a polymer chain composed of a repetitive sugar– phosphate backbone with a series of bases protruding from it.
–The Structure of DNA | Video by MITx Bio
