Vermont Barbers and Cosmetologists Practice Exam

Disulfide bonds are sulfur-to-sulfur covalent bonds that are important for the stability of proteins and hair. They can be broken by reducing agents, which apply chemical solutions that break the bond. B, C, and D are not common methods for breaking disulfide bonds and may not be as effective or safe as using a reducing agent. For example, heat treatment and UV radiation could potentially damage the protein or hair structure instead of specifically targeting the disulfide bond. Using moisturizing shampoo may help to keep hair and proteins healthy, but it does not have the specific chemical properties needed to break disulfide bonds. Therefore, A is the correct answer because it accurately describes an effective method for breaking disulfide bonds.