Illustrated Glossary of Organic Chemistry

Tertiary structure: The three-dimensional structure of a biopolymer, as defined by the spatial coordinates of all the atoms. In a protein, tertiary structure is controlled by disulfide bridges and folding in response to environment. The tertiary structure of DNA is the supercoil.

Amino acid side chain orientation	Polar environment (e.g., water)	Nonpolar environment (e.g., cell membrane core)
Hydrophilic side chains	point outwards	point inwards
Hydrophobic side chains	point inwards	point outwards

DNA tertiary structure is the supercoil.