chitin

(noun)

A complex polysaccharide, a polymer of N-acetylglucosamine, found in the exoskeletons of arthropods and in the cell walls of fungi; thought to be responsible for some forms of asthma in humans.

Related Terms

Examples of chitin in the following topics:

  • Phylum Arthropoda

    • Arthropods are the largest grouping of animals all of which have jointed legs and an exoskeleton made of chitin.
    • Arthropods also show the presence of an exoskeleton made principally of chitin, which is a waterproof, tough polysaccharide.
    • It is made up of two layers: the epicuticle, which is a thin, waxy, water-resistant outer layer containing no chitin; and the chitinous procuticle, which is beneath the epicuticle.
    • Chitin is a tough, flexible polysaccharide.

  • Chytridiomycota: The Chytrids

    • Like all fungi, chytrids have chitin in their cell walls, but one group of chytrids has both cellulose and chitin in the cell wall.

  • Phylum Mollusca

    • Additionally, a tongue-like organ called a radula, which bears chitinous tooth-like ornamentation, is present in many species, serving to shred or scrape food.
    • The mantle (also known as the pallium) is the dorsal epidermis in mollusks; shelled mollusks are specialized to secrete a chitinous and hard calcareous shell.

  • Limits on Animal Size and Shape

    • As the tough and resistant outer cover of an arthropod, the exoskeleton may be constructed of a tough polymer, such as chitin, and is often biomineralized with materials, such as calcium carbonate.
    • The increasing thickness of the chitin necessary to support this weight limits most animals with an exoskeleton to a relatively-small size.

  • Types of Skeletal Systems

    • Arthropods, such as crabs and lobsters, have exoskeletons that consist of 30–50 percent chitin, a polysaccharide derivative of glucose that is a strong-but-flexible material.
    • Chitin is secreted by the epidermal cells.

  • Carbohydrate Molecules

    • Starch, glycogen, cellulose, and chitin are primary examples of polysaccharides.
    • This exoskeleton is made of chitin, which is a polysaccharide-containing nitrogen.
    • Chitin is also a major component of fungal cell walls.

  • Virus Attachment and Genome Entry

    • Plants have a rigid cell wall made of cellulose, and fungi one of chitin, so most viruses can get inside these cells only after trauma to the cell wall.

  • Overview of Gram-Positive Bacteria and Actinobacteria

    • Actinobacteria include some of the most common soil life, freshwater life, and marine life, playing an important role in the decomposition of organic materials, such as cellulose and chitin; thereby playing a vital part in organic matter turnover and carbon cycle.

  • Cell Walls of Archaea

    • Likewise, archaea do not produce walls of cellulose (as do plants) or chitin (as do fungi).

  • Actinobacteria (High G + C Gram-Positive Bacteria)

    • Actinobacteria include some of the most common soil life, freshwater life, and marine life, playing an important role in decomposition of organic materials, such as cellulose and chitin, and thereby playing a vital part in organic matter turnover and carbon cycle.