The aim of this lecture is to present on Structure of Nucleotide. A nucleotide is made of 3 components: A Pentose sugar, the sugar in DNA is deoxyribose and the sugar in RNA is ribose. The basic building block of DNA is the nucleotide. The nucleotide in DNA consists of a sugar (deoxyribose), one of four bases (cytosine (C), thymine (T), adenine (A), guanine (G)), and a phosphate. Phosphate groups are important because they link the sugar on one nucleotide onto the phosphate of the next nucleotide to make a polynucleotide.