Genetics relies on chemistry to explain phenomena related to the field. The structure of DNA is based on chemistry. In fact, when James Watson and Francis Crick discovered the structure of DNA, they did so by building models based on the laws of chemistry. Chemistry is also closely related to the structure and function of one of the main products of DNA: proteins. Chemistry dictates the structure of DNA. DNA is a polymer of monomers called nucleic acids. These consist of a nitrogen base, a phosphate group and a sugar. It is the negative charge of the phosphate group that makes DNA an acid. There are 4 different bases: adenine, thymine, guanine and cytosine. In groups of three, these four bases can code for any protein encoded in an organism's genome. Two strands of nucleic acids stack on top of each other in a double helix. The backbone of nucleic acids is made up of the interaction between phosphate groups and hydroxide groups of nucleic acids. These are held together by covalent bonds called phosphodiester bonds. The helix itself is held together by hydrogen bonds. Although h...