Nevada State Board of Cosmetology Practice Exam

What can weaken a disulfide bond?

1. Drying

2. Styling with gel

3. Bleaching and coloring hair

4. Regular cutting

The correct answer is: Bleaching and coloring hair

Disulfide bonds are strong chemical bonds that help maintain the shape and structure of proteins in hair. Bleaching and coloring hair can be damaging as it involves the use of harsh chemicals, which can break down these disulfide bonds and weaken them. Therefore, this is the only option that directly weakens disulfide bonds and is the correct answer. The other options are incorrect because they do not directly affect the disulfide bonds. Drying and styling with gel may cause damage to hair, but it does not specifically target the disulfide bonds. Regular cutting helps to keep hair healthy, but it does not necessarily weaken the bonds. Therefore, none of these options can be considered as the correct answer.