Describe and differentiate among the primary, secondary, and tertiary structures of a protein. To ...

Primary protein structure refers to the sequence of amino acids on the polypeptide chain, which is determined by the gene nucleotide sequence. Secondary structure is the regular folding and twisting of a single polypeptide chain into a variety of shapes. This can be ascribed to weak bonds (electrostatic or hydrogen bonds) between NH and CO groups that are near each other on the chain. Tertiary structure refers to the folding and twisting of the amino acid chain into a three-dimensional conformation. This can be ascribed to interactions among R-groups of individual amino acids.