4.4 THE DNA and RNA BASES

In order to understand the structure and properties of DNA and RNA, we need to look at their structural components.
We begin with certain heterocyclic aromatic compounds called pyrimidines and purines.

• Pyrimidine and purine are the names of the parent compounds of two types of nitrogen-containing heterocyclic aromatic compounds.
• Nitrogenous bases are heterocyclic amines
• Cyclic compounds with at least 1 N atom in the ring structure
• Purines are a double ring structure
• A 6-member ring fused to a 5-member ring
• Pyrimidines consist of a single 6-membered ring

4.5. THE NUCLEOSIDES