This image depicts the chemical structure of cytosine. It shows a hexagonal ring with nitrogen atoms at positions 1 and 3, and a primary amine group attached to carbon 4. The two remaining positions ...

Chemical structure of guanine, showing its double-ring purine structure and the functional groups involved in hydrogen bonding with cytosine. (Image: Public Domain) Guanine has the chemical formula ...

We’re celebrating 180 years of Scientific American. Explore our legacy of discovery and look ahead to the future. In 1957, just four years after Francis Crick and other scientists solved the riddle of ...