Main objective of this lecture is to present on DNA Structure. Nucleic acids first called “nuclein” because they were isolated from cell nuclei by F. Miescher in 1869. Each nucleotide is composed of a Phosphate group; a five – carbon sugar (or Pentose), and a cyclic nitrogen containing compound called a base. The backbone of DNA is based on a repeated pattern of a sugar group and a phosphate group. The full name of DNA, deoxyribonucleic acid, gives you the name of the sugar present – deoxyribose.