Question

The bond that determines the secondary structure of proteins is:

• A. covalent bond
• B. sulphur linkage
• C. hydrogen bond
• D. lecithin

Answer 1

The correct option is C hydrogen bond

The bond that determines the secondary structure of proteins is hydrogen bond. Depending on hydrogen bonding, two main types of secondary structure are the $\alpha$-helix and the $\beta$-sheet.
The $\alpha$-helix is a right-handed coiled strand. The side-chain substituents of the amino acid groups in an $\alpha$-helix extend to the outside. Hydrogen bonds form between the oxygen of the $C=O$ of each peptide bond in the strand and the hydrogen of the $N-H$ group of the peptide bond four amino acids below it in the helix.
The hydrogen bonding in a $\beta$-sheet is between strands (inter-strand) rather than within strands (intra-strand). The sheet conformation consists of pairs of strands lying side-by-side.