How does B-keratin differ from A-keratin?

B-keratin and A-keratin are two different types of keratin found in various forms of biological tissues. B-keratin is primarily present in the structure of feathers, scales, and hooves, whereas A-keratin is typically found in mammals’ hair and skin.

The correct answer highlights that B-keratin has less moisture and fat compared to A-keratin. This distinction is important because it reflects the structural and functional adaptations of these proteins to their respective roles in different organisms. The composition of B-keratin, being harder and more rigid, is suited for providing protection and structural support in non-mammalian species. Conversely, A-keratin retains more moisture and fat, which contributes to its flexibility and resilience in mammalian hair and skin.

Understanding this difference helps explain the varying physical properties and functions of keratin in different biological contexts, emphasizing the importance of keratin types in evolutionary adaptations.