T Level Biology Practice Test 2025 – Complete Exam Prep

Keratin is the primary protein found in keratinocytes, which are the predominant cell type in the outermost layer of the skin, known as the epidermis. Keratinocytes are responsible for the production of keratin, a fibrous protein that provides structural strength and protection to the skin. Keratin plays a crucial role in forming a waterproof barrier, thus aiding in preventing water loss and protecting underlying tissues from environmental damage, pathogens, and physical abrasions.

Collagen, while also a significant protein in the body, is primarily found in connective tissues such as skin, bones, and cartilage, providing tensile strength and structural support. Elastin provides elasticity to tissues and is found mainly in the dermis of the skin, enabling it to return to its original shape after stretching. Myosin is a motor protein involved in muscle contraction and is not related to keratinocytes or skin structure. Therefore, keratin stands out as the essential protein associated specifically with keratinocytes.