Chemistry - Biomolecules Question with Solution | TestHub

The secondary structure of a protein refers to the shape in which a long polypeptide chain can exist.

They are found to exist in two different types of structures, namely $\alpha$-helix and $\beta$-pleated sheet structures.

These structures arise due to the regular folding of the backbone of the polypeptide chain due to hydrogen bonding between the $-\text{C}=\text{O}$ and $-\text{NH}-$ groups of the peptide bonds.

Therefore, the secondary structure of a protein is determined by hydrogen bonds.

Answer: hydrogen bond