Which of the Following Actions Would Affect the Secondary, but Not

Question

Which of the following actions would affect the secondary, but not primary, structure of a protein?
A)change the sequence of amino acids
B)break the ionic bonds between amino acids
C)break the hydrogen bonds between amino acids
D)disrupt the interactions between two different polypeptide chains

Accepted Answer

The secondary structure of a protein is defined by its hydrogen bonding pattern, specifically between the backbone amide groups. If these bonds are broken, it can disrupt the secondary structure while leaving primary structure (amino acid sequence) intact. Changes to amino acid sequence (A) would affect both primary and secondary structure, breakage of ionic bonds (B) would affect tertiary and quaternary structure but not secondary, and disruption of interactions between different chains (D) would affect tertiary or quaternary but not secondary structure of a protein.