Adenine and guanine, the two most common purines in DNA and RNA, share this core structure, which is crucial for forming the base pairs in nucleic acids. (Image: Wikimedia Commons, Public Domain) ...

If a nitrogenous base is composed of two of these rings, it is known as a purine, but if it is only composed of one ring, it is called a pyrimidine. Purines and pyrimidines naturally bind to one ...

The pyrimidines, thymine (DNA), uracil (RNA), and cytosine are shown on top while the purines, adenine and guanine, are shown at the bottom. (Image: adapted from Wikimedia Commons, public domain) The ...