The secondary structure of a protein, such as the alpha helix, is maintained by
- A. peptide bonds between amino acids
- B. ionic bonds between side chains only
- C. hydrogen bonds between the carbonyl and amide groups of the backbone
- D. disulphide bridges only
Explanation
Regular coiling or pleating arises because each carbonyl oxygen hydrogen bonds to an amide hydrogen further along the same chain, giving the alpha helix and the beta pleated sheet. Peptide bonds create the primary sequence, and side chain interactions such as disulphide bridges belong to the tertiary level. Heat breaks the weak hydrogen bonds and the structure unwinds, which is denaturation.
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