Weak physical side bonds that are the result of an attraction between negative and positive electrical charges are

• A. Hydrogen bonds
• B. Salt bonds
• C. Peptide bonds
• D. Disulfide bonds

Answer: (B)

Ionic interactions between opposite charges on amino acid side chains create the salt bonds. These are weak, noncovalent attractions that form when a positively charged side chain (like lysine) meets a negatively charged one (like aspartate or glutamate). Because they rely on electrical attraction rather than sharing electrons, they’re easily disrupted by changes in pH or by moisture, which is why altering the environment can temporarily alter the shape of the structure they stabilize. Hydrogen bonds are also electrostatic, but they involve partial charges and are even more fragile; peptide bonds link amino acids covalently in a chain, and disulfide bonds are covalent cross-links between cysteine residues. The description given matches salt bonds because of the charge-based, weaker ionic interaction.