Proteins

By: Kimberly Rhee

Definition & Interesting Facts

A class of nitrogenous organic compounds that consist of large molecules composed of one or more long chains of amino acids by polypeptide bonds and have distinct and varied three- dimensional structures, usually containing alpha helices and beta sheets as well as looping and folded chains, and are an part of all living organisms, especially as structural components of body tissues such as muscle, hair, collagen, etc., and as enzymes and antibodies.


  • Keratin, fur, skin, hair, scales, beaks,feathers, horns, hooves, and similar structures; the collagen are the most common things found in protein.
  • Animals, constituents of flesh and connective tissues; and the actin and myosin proteins found in muscle tissue are the most abundant proteins that people know of.
  • Some of these thermostat include the nucleoproteins (protein plus DNA and RNA) that have the blueprints for the synthesis of all proteins. Other functional thermostats are enzymes used to trigger organic developments; hormonal proteins, that begin and end cellular metabolism; myosin and actin, that keep the muscles form re ceding ; hemoglobin and lipoprotein, that moves protein around the circulatory system; the antigen albumin and antigen protein, that control osmotic pressure during osmosis and contains water equally in cells.
  • Bone and cartilage contribute strength and support for muscles, and the structural proteins found in skin, hair, and nails sustain a tough outer covering to the body.

Functions of Proteins

More Functions of Proteins

Hemoglobin- transport molecules

Collagen- skin and bone structure

Immune System- the body's defense against infectious organisms

Elastin- skin structure-makes it stretchy

Types of Proteins

Enzymes- essential to all chemical reactions

Hormones- body`s chemical messengers

Antibodies- help fight foreign substances

Keratin- Makes up hair and fingernails

Tendons- linking muscles to bone

Skin, Hair, and Nails

  • Hair shaft consists of died hair cells, that is made of a protein called keratin, which is pliable, but can be strengthened and stiffened by increasing the number of disulfide cross-bridges that link different chains together. The shaft is composed of three layers. The outer layer is your cuticle, the middle layer is your cortex, and the inner layer is your medulla. The hair color you see is the result of pigment cells in the medulla and cortex.
  • From the time of ancient Rome through nineteenth-century England, the crushed leaves of a shrub called Lawsonia inermis were used to make a dye called henna. Women still use henna to dye their hair red.