Western Governors University (WGU) CHEM3501 C624 Biochemistry Objective Assessment Practice Exam

The secondary structure of a protein is primarily determined by the sequence of amino acids. This sequence dictates how the protein folds into structures such as alpha helices and beta sheets, which are stabilized by hydrogen bonds between the backbone atoms in the polypeptide chain. The specific arrangement of amino acids influences how these interactions occur, leading to the formation of these secondary structural elements.

While interactions between R groups can influence the overall folding and stability of the protein, they are more relevant for determining the tertiary and quaternary structures rather than the secondary structure. The peptide composition of just two amino acids does not account for the complexity of folding that occurs in longer polypeptide chains required for secondary structure formation. Additionally, the overall 3D shape of the protein corresponds to tertiary or quaternary structures rather than the specific configurations noted within the secondary structure itself. Thus, the sequence of amino acids is the defining factor for establishing the secondary structure of a protein.