What is keratin?

Keratin is a fibrous protein that plays a crucial role in providing structure and protection to various tissues in the body, particularly the skin. It is a key component of the epidermis, the outermost layer of the skin, where it forms a barrier that helps to keep moisture in and protect underlying tissues from environmental damage, pathogens, and physical harm. Keratin is also found in hair and nails, contributing to their strength and resilience.

In contrast, the other options do not accurately describe keratin. While melanin is involved in skin pigmentation, it is not an enzyme produced by keratin. The generation of new tissue is more accurately associated with keratinocytes, the skin cells that produce keratin, rather than keratin itself. Lipids are indeed important for skin hydration, but they are a different class of molecules and do not fulfill the structural role of keratin in epidermal tissues. Therefore, identifying keratin specifically as a fibrous protein found in the epidermal tissues illustrates its fundamental biological function.