Answer to Question #259556 in General Chemistry for Pogi

Question

 What structural feature in α-keratin makes fingernails harder than skin?

Answer 1

Hard and soft

Hard alpha-keratins, such as those found in nails, have a higher cysteine content in their primary structure. This causes an increase in disulfide bonds that are able to stabilize the keratin structure, allowing it to resist a higher level of force before fracture.