What is called nucleotide? Md. Saifur Rahman A nucleotide is the building block of DNA and RNA that consists of a base (one of four chemicals: adenine, thymine, guanine, and cytosine), a molecule of sugar, and one of phosphoric acid.Read more:What is glass fire? What is the Paris accord? What is a diaphragm? What is interphase? What is histology? What is the endocrine gland? What is called nucleotide? What is cell division? What is karyokinesis? What is osmoregulation? What does attraction fiber mean? What is spindle fiber? What is cytokinesis?