Which statement about Alpha keratin is correct?

• A. Alpha keratin is softer than Beta keratin
• B. Alpha keratin is harder than Beta keratin
• C. Alpha keratin is more brittle than Beta keratin
• D. Alpha keratin is unrelated to Beta keratin

Answer: (A)

The idea being tested is how protein structure affects how hard or soft a material is. Alpha keratin and beta keratin are both keratins but have different structural arrangements. Alpha keratin, found in hair, skin, and nails, is built from alpha-helices that form flexible, resilient fibers. Beta keratin, found in feathers, beaks, and reptile scales, uses beta-pleated sheets that stack into a much stiffer, more rigid material. Because of this, beta keratin tends to be harder and more brittle, while alpha keratin is softer and more flexible. So the statement that alpha keratin is softer than beta keratin aligns with how their structures translate to mechanical properties in real tissues, making it the best choice. The idea that alpha keratin would be harder or unrelated to beta keratin clashes with the known differences in their organization and roles in organisms.