A nucleotide is made up of a phosphate group, a sugar group and a nitrogenous base.
Nucleotides are the building blocks of Nucleic acids which can either be RNA or DNA. These differ in that the sugar of the nucleotides making up RNA is ribose sugar and that of DNA is deoxyribose sugar. The nitrogenous bases of RNA are adenine, guanine, cytosine and uracil. Uracil and adenine are complementary like guanine and cytosine. In a DNA molecule, uracil is replaced by thymine. DNA is a double helix while RNA is a single strand.
