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Chitin (C 8 H 13 O 5 N) n (/ ˈ k aɪ t ɪ n / KY-tin) is a long-chain polymer of N-acetylglucosamine, an amide derivative of glucose. Chitin is the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chitin are produced each year in the biosphere. [1]
Arthropod cuticle is a biological composite material, consisting of two main portions: fibrous chains of alpha-chitin within a matrix of silk-like and globular proteins, of which the best-known is the rubbery protein called resilin. The relative abundance of these two main components varies from approximately 50/50 to 80/20 chitin protein, with ...
Like cellulose, chitin is an abundant biopolymer that is relatively resistant to degradation. [17] Many mammals can digest chitin and the specific chitinase levels in vertebrate species are adapted to their feeding behaviours. [18] Certain fish are able to digest chitin. [19] Chitinases have been isolated from the stomachs of mammals, including ...
H. Harris, publishing in the British Journal of Dermatology in 1947, wrote Native Americans have the least body hair, Han Chinese people and black people have little body hair, white people have more body hair than black people and Ainu have the most body hair. [18] Anthropologist Arnold Henry Savage Landor described the Ainu as having hairy ...
Setae in oligochaetes (a group including earthworms) are largely composed of chitin. [1] They are classified according to the limb to which they are attached; for instance, notosetae are attached to notopodia; neurosetae to neuropodia. [2] Diptera setae are bristles present throughout the body and function as mechanoreceptors.
Human hair is approximately 14% cysteine. The pungent smells of burning hair and skin are due to the volatile sulfur compounds formed. Extensive disulfide bonding contributes to the insolubility of keratins, except in a small number of solvents such as dissociating or reducing agents. A human toe nail that fell off after a small trauma.
The human body is the entire structure of a human being. It is composed of many different types of cells that together create tissues and subsequently organs and then organ systems . The external human body consists of a head , hair , neck , torso (which includes the thorax and abdomen ), genitals , arms , hands , legs , and feet .
They can be identified by the fact that they express "hard", "trichocyte" or "hair" keratin proteins. [1] These are modified keratins containing large amounts of the amino acid cysteine , which facilitates chemical cross-linking of these proteins to form the tough material from which hair and nail is composed.