Figure 2.

Structural models of amino acids and nucleotides. The left figure shows a protein structure and a closeup of three amino acids. The right figure shows the nucleic structure of DNA. Blue represents nitrogen atoms, red represents oxygen atoms, orange represents phosphates, light gray shows the side chain carbons and dark gray shows the backbone carbons. Each side chain can have 20 different conformations for amino acids and five different kinds of DNA/RNA nucleotides.