Answer: Intermolecular hydrogen bonds between backbone groups.
- A Intermolecular hydrogen bonds between backbone groups
- B Disulfide bonds formed between adjacent cysteine residues
- C Ionic bonds between oppositely charged side chains
- D Hydrophobic interactions between nonpolar side chains
Correct answer: A. Intermolecular hydrogen bonds between backbone groups
Explanation: Beta-sheets are stabilised by hydrogen bonds between NH and C=O groups on adjacent parallel or antiparallel chains.
Two amino acids join via a condensation reaction: the carboxyl -OH of one and an amine -H of the other are eliminated as water, leaving a peptide bond (-CO-NH-) linking them into a dipeptide; repeating this builds a full protein chain.
Concept context
The chemistry of life: carbohydrates, proteins, lipids, nucleic acids, enzymes, and vitamins. Understand their structures, classification, and biological functions. Highly relevant for NEET and Class 12 board exams.