Dictionary > Keratin

Keratin

Definition
noun, plural: keratins
One of the fibrous structural proteins, and is a constituent of hair, nails, skin, feathers, hooves, horns, etc.
Supplement
Scleroproteins or the fibrous proteins are one of the three major types of proteins; the other two are spheroproteins and membrane proteins. Scleroproteins are characterized by their long protein filaments. They act as structural proteins. They are usually water-insoluble. Some of the scleroproteins are keratin, collagen, elastin, and fibroin.
Keratins are fibrous structural proteins that constitute various biological structures such as hair, nails, skin, feathers, hooves, horns, etc. They are made up of coiled polypeptide chains and when they combine they form supercoils.
Keratins protect epithelial cells from damage. Skin cells that are constantly exposed to pressure and rubbing leads to the formation of calluses. The skin thickens and the epidermal cells undergo cornification. Cornification is a process in which a keratinized layer of epidermis forms and serves as an epidermal barrier. During cornification, keratin fills up the cell resulting in the loss of cytoplasmic organelles and the cessation of metabolism. Ultimately, the fully keratinized cells undergo a programmed cell death.
Word origin: Greek keras (horn) + –in
See also:

Related term(s):

  • keratinization
  • Related form(s):

    • keratinous (adjective, relating to keratin; horny)


    You will also like...

    dinosaurs
    The Dinosaurs

    Dinosaurs represented a major turn in the evolutionary development of organisms on Earth. The first dinosaurs were presu..

    Oligodendrocyte and Schwann cell
    The Central Nervous System

    Myelin sheath is essential for a faster conductivity of signals. Know more about this feature of some neurons in the Cen..

    Early Earth
    The Origins of Life

    This tutorial digs into the past to investigate the origins of life. The section is split into geological periods in the..

    Schematic diagram of bacterial lactose operon
    Gene Action – Operon Hypothesis

    This tutorial focuses on the way genes control and determine every aspect of the body. It describes lac operon as an exa..

    Lotic community of algal species
    Lotic Communities & Algae

    Lotic communities have conditions that are rather harsh for typical plants. Thus, the diversity of plant species in loti..

    Ploidy
    Polyploidy

    Humans are diploid creatures. This means that for every chromosome in the body, there is another one to match it. Howeve..