Redseal Hairstyling License Practice Test

Which bond is most responsible for the strength of hair?

1. Hydrogen bond

2. Salt bond

3. Covalent bond

4. Peptide bond

The correct answer is: Covalent bond

The covalent bond is indeed the most responsible for the strength of hair. This type of bond is formed when atoms share electrons, creating a strong and stable connection between the individual keratin molecules that makeup hair strands. Specifically, the covalent bonds in hair are primarily found in the peptide bonds that link amino acids together to form keratin, which is the main structural protein in hair. These bonds provide hair with its overall strength and resilience, making it less prone to breakage under normal conditions compared to the bonds that involve weaker interactions, such as hydrogen bonds or salt bonds. While hydrogen bonds and salt bonds do play a role in the temporary structure and shape of the hair, they do not provide the same level of strength. Hydrogen bonds, for example, are easily broken by water and heat, while salt bonds are influenced by the pH of the environment. Therefore, the covalent bonds contribute significantly to the durability and integrity of hair, making them crucial for its overall strength.