The structure of DNA is a double helix, resembling a twisted ladder, composed of two strands of nucleotides linked by sugar-phosphate backbones, with nitrogenous bases (adenine, thymine, guanine, and cytosine) pairing specifically (A with T, C with G).

DNA is the long molecule that contains your unique genetic code. A bit like a recipe book, which holds the instructions your cells need to make all the proteins in your body.