• BIO 180
  • UNIT 1. INORGANIC CHEMISTRY
  • UNIT 2. INTERMOLECULAR FORCES, WATER, AND ACIDS AND BASES
  • UNIT 3. CARBOHYDRATES
  • UNIT 4. LIPIDS, NUCLEIC ACIDS, AND PROTEINS
  • UNIT 5. CELL MEMBRANES-STRUCTURE AND CELL FUNCTION
  • UNIT 6. PROKARYOTES AND VIRUSES
  • UNIT 7. ENERGY BALANCE
  • UNIT 8. GLYCOLYSIS AND CITRIC ACID CYCLE
  • UNIT 9. ELECTRON TRANSPORT CHAIN
  • UNIT 10. PHOTOSYSNTHESIS
  • UNIT 11. CELLULAR TRANSPORT AND CELLULAR SIGNALING
  • UNIT 12. CELL DIVISION AND CANCER
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  • Translations
  • 4.3.5

    Classes of Proteins

    There are two major classes or types of proteins: globular and fibrous proteins. Globular means globe-like. Hemoglobin is a good example of a globular protein. Globular proteins are quite fragile and can be inactivated (denatured) by things like heat (think of the protein albumin in an egg white when you fry it), organic solvents, or strong ionic solutions.

    Fibrous proteins are much stronger and tougher. As the name implies, these proteins are more like ropes or cables. Fibrous proteins give the body structural support and help it resist mechanical stress. Common examples of body structures containing fibrous proteins include bone, cartilage, tendons (which anchor muscles to bones), ligaments (which anchor bones to other bones), and capsules around our internal organs.

    The two images below show the molecular image representations of a globular (first) and a fibrous protein (second).

    Molecular Image Representations of a Globular

    Globular Protein. File: Hras surface colored by conservation.png; Author: Elaine Meng;
    Site: https://books.byui.edu/-nhIb;
    License: licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

    Molecular Image Representations of a Fibrous Protein

    Fibrous Protein. File:1bkv collagen 02.png; Author: Nevit Dilmen;
    Site: https://books.byui.edu/-RGFQ;
    License: licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

    This content is provided to you freely by BYU-I Books.

    Access it online or download it at https://books.byui.edu/bio_180/435___classes_of_pro.