system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Strength and rigidity in keratin is due to -
assistant
The correct answer is  Keratin is a protein present in the hair, nails and outer layer of skin. Keratin is almost completely comprised of alpha-helices (secondary structure) Two alpha helix are wound around one another to form super helix. Strength and rigidity in keratin is due to Cysteine because of its ability to form disulphide bonds. Number of disulphide bonds is directly propoional to rigidity of keratin i.e. more the disulphide bonds, harder the keratin.