Missouri Board of Cosmetology Practice Exam

During the perming process, the primary bonds that are broken are disulfide bonds. These bonds are strong covalent bonds that form between the sulfur atoms of cysteine molecules in the hair proteins. The perming solution typically contains a chemical agent, such as ammonium thioglycolate, that breaks these disulfide bonds, allowing the hair to be reshaped.

When disulfide bonds are broken, the hair can then be molded into a new shape around perm rods. Once the hair is reshaped, a neutralizing solution is applied, which re-forms the disulfide bonds in their new configuration, thereby creating lasting curls or waves in the hair.

Other types of bonds, such as hydrogen and ionic bonds, are much weaker and can be temporarily altered through physical styling methods like using heat or water, but they do not play a significant role in the chemical changes during the perming process. Covalent bonds are generally strong and stable and are not typically broken during hair styling beyond the specific disulfide bonds that are targeted by perm solutions.