Describe the structure of DNA.

DNA is comprised of many 'building blocks' known as deoxyribose nucleoside triphosphates (dNTPs). Each dNTP is made of a base (adenine, guanine, cytosine or thymine), bonded to a 5-carbon sugar molecule and a phosphate molecule. When a DNA molecule is being built, the dNTPs lose 2 of their phosphate molecules, providing energy required for the bonds to form between the phosphates of the DNA molecule's 'backbone.' Each base forms hydrogen bonds with its complementary base; adenine bonds with thymine, and cytosine bonds with guanine. These hydrogen bonds between bases anneal the strands of DNA in an antiparallel, double helix configuration.