Topic overview

Start with the big picture

Primary structure is the linear sequence of monomers linked by covalent bonds. Local backbone hydrogen bonding produces secondary structures such as α-helices and β-sheets. Tertiary structure is the three-dimensional fold of a single chain, while quaternary structure describes the arrangement of multiple subunits. Larger supramolecular assemblies, including micelles and lipid bilayers, form through reversible non-covalent interactions. The hydrophobic effect is a major driver of folding in aqueous environments, alongside hydrogen bonding, ionic interactions, dispersion forces, and disulfides. Folding reflects a balance of enthalpic and entropic contributions, and cooperative transitions can occur. The lesson also considers how chaperones, denaturants, and allosteric coupling relate to structural organization.