Scientists Say: Keratin
This protein makes up our hair, skin and nails

Hair is made of keratin.
Timothy Krause/Flickr (CC BY 2.0)
Keratin (noun, “CARE-ah-tin”)
A protein that makes up hair, nails and skin. These long, fibrous molecules protect cells from damage.
In a sentence
Keratin is the tough fiber that makes up a whale’s baleen.
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Power Words
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baleen A long plate made of keratin (the same material as your fingernails or hair). Baleen whales have many plates of baleen in their mouths instead of teeth. To feed, a baleen whale swims with its mouth open, collecting plankton-filled water. Then it pushes water out with its enormous tongue. Plankton in the water become trapped in the baleen, and the whale then swallows the tiny floating animals.
keratin A protein that makes up your hair, nails and skin.