DNA stands for deoxyribonucleic acid. DNA is a nucleic acid. This means it has a structure that consists of a backbone comprised of alternating sugar and phosphate molecules, and each of the sugar molecules is bound to a nucleotide base. Two parallel polymers of nucleosides (the name for one unit of sugar and base), bound by phosphodiester bonds, are held together in a double-helical structure by hydrogen bonds between complimentary base pairs. The nucleic acids contain only four bases each, and DNA is comprised of adenine, cytosine, thymine and guanine.
Because our genes are comprised of DNA, DNA is the hereditary material that is passed from parent to offspring. It is the sequence of nucleotide bases in genes that dictates the sequence of amino acids in the encoded protein product.