name two fibres which are made of proteins
feathers hair wool fur silk
title: Fiber crop text: Fiber crop Fiber crops are field crops grown for their fibers, which are traditionally used to make paper, cloth, or rope. They are organized into 3 main groups—textile fibers (used in production of cloth), cordage fibers (used in production of rope), and filling fibers (used to stuff upholstery and mattresses). They are a type of natural fiber. Fiber crops are characterized by having a large concentration of cellulose, which is what gives them their strength. The fibers may be chemically modified, like in viscose (used to make rayon and cellophane). In recent years, materials scientists have begun exploring further use title: Dietary fiber text: Dietary fiber Dietary fiber or roughage is the portion of plant-derived food that cannot be completely broken down by digestive enzymes. It has two main components: Dietary fiber consists of non-starch polysaccharides and other plant components such as cellulose, resistant starch, resistant dextrins, inulin, lignins, chitins, pectins, beta-glucans, and oligosaccharides. Dietary fibers can act by changing the nature of the contents of the gastrointestinal tract and by changing how other nutrients and chemicals are absorbed. Some types of soluble fiber absorb water to become a gelatinous, viscous substance which may or may not be fermented by bacteria in the digestive title: Natural fiber text: over clothing made of synthetic fibers by people living in hot and humid climates. Natural fibers are made from plant, animal, and mineral sources. Natural fibers can be classified according to their origin. Animal fibers generally comprise proteins such as collagen, keratin and fibroin; examples include silk, sinew, wool, catgut, angora, mohair and alpaca. Chitin is the second most abundant natural polymer in the world, with collagen being the first. It is a “linear polysaccharide of β-(1-4)-2-acetamido-2-deoxy-D-glucose”. Chitin is highly crystalline and is usually composed of chains organized in a β sheet. Due to its high crystallinity and chemical structure, title: Azlon text: Azlon Azlon is a synthetic textile fiber composed of protein material derived from natural sources such as soy, peanut, milk or corn. Currently it is used in clothing. Under the "Textile Labelling and Advertising Regulations", Section 26(f), Azlon is defined as any fiber made from regenerated protein. The name "Azlon" is regulated by the Federal Trade Commission, § 303.7(g) "Rules and Regulations Under the Textile Fiber Products Identification Act". However, there is currently no domestic production. Azlon is the common generic name for all man-made protein fibers. Aralac was a registered trademark of Aralac, Inc., a division of National Dairy title: Elastic fiber text: Elastic fiber Elastic fibers (or yellow fibers) are bundles of proteins (elastin) found in extracellular matrix of connective tissue and produced by fibroblasts and smooth muscle cells in arteries. These fibers can stretch up to 1.5 times their length, and snap back to their original length when relaxed. Elastic fibers include elastin, elaunin and oxytalan. Elastic tissue is classified as "connective tissue proper". The elastic fiber is formed from the elastic microfibril (consisting of numerous proteins such as microfibrillar-associated glycoproteins, fibrillin, fibullin, and the elastin receptor) and amorphous elastin. The microfibril scaffolds and organizes the deposition of amorphous elastin. Amorphous