Nucleotides are one of the basic units for another class of biomolecules: the ones that join together to form your DNA and RNA (the long names for these are deoxyribonucleic acid and ribonucleic acid). DNA and RNA are the macromolecules that store the genetic information in your body. A nucleotide consists of three parts: a nitrogenous base, a sugar, and a phosphate group. The identity of the nitrogenous base determines which “letter” in the genetic code is associated with the nucleotide, while the type of sugar determines whether the nucleotide is a ribonucleotide or a deoxyribonucleotide (which essentially just tells us whether it’s going to be a part of RNA or a part of DNA).