Which bonds must be broken to allow rearrangement of the hair during a perm?

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

Answer: (A)

Disulfide bonds must be broken to allow rearrangement of the hair during a perm. The chemical process uses a reducing agent to cut the sulfur-sulfur cross-links between cysteine units in the hair’s keratin. Once these disulfide bonds are broken, the hair can be reshaped around perm rods. After the wrapping, a neutralizer oxidizes the hair, re-forming new disulfide bonds in the new configuration so the curl stays in place. Hydrogen bonds and other weaker interactions can temporarily change with moisture and heat, but they don’t drive the permanent rearrangement. Peptide bonds, the backbone links in proteins, aren’t broken in a standard perm.