A.T. A.Kossel and study on chemical composition of Levene nucleic acid. Nucleic acid from animal cells, has main elements nitrogen and is therefore called a Nucleotide base a treasure base Nitrogenous base which has the structure or chemistry of different types are divided into 2.
-A Purine base with the primary structure consists of 2 ring band is divided into two types, namely Adenine Guanine.
-A Pyrimidine base, whose primary structure consists of a ring is the circle is divided into 2 types: 1 Thymine Cytosine.