Cellular Basics

Prokaryotic and Eukaryotic Cells

What is keratin?

All of the surface cells of the body (except those in the eyes) contain a molecule called keratin, a fibrous protein that is particularly well suited to withstand abrasions. Keratin includes hair, nails, horns, hooves, wool, feathers, and the epithelial cells in the skin’s outermost layer. In general, specific bonds in the keratin make this protein impervious to attack by certain enzymes and completely insoluble in hot or cold water.

Certain cells, like those of the nails and hair, have increased amounts of keratin that provide extra strength, helping them maintain their shape. Whether it is in the claws on the toes of your cat, the horns on the head of your favorite cow, or the five million hairs that cover your body, keratin strengthens and protects organisms from everyday wear and tear.


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