In this A-Level Biology Lesson “A-Level biology: Proteins - The Shape and Function of Enzymes,  Antibodies, Transport Proteins and Structural Proteins" You'll learn about the structure and function of some frequently encountered protein during the course of your A-level biology. Following the Learning outcomes and brief introduction you'll learn that proteins are either globular or fibrous. Next we'll take a look at some examples of proteins including the familiar category the enzymes. Moving on next to structural proteins and Collagen. We'll wrap up this lesson with a look at transport proteins and the structure of an antibody.

Proteins are the most complex and most diverse group of biological molecules.  They have an astonishing range of different structures and functions, for example: -

 Structural proteins: - e.g. collagen (bone, cartilage, tendon), keratin (hair), actin (muscle)

Enzymes: - e.g. Amylase, Lipase, Lactase, Pepsin, etc (>10,000 others)

Transport proteins: - e.g. haemoglobin (oxygen), transferrin (iron)

Pumps: - e.g. Na+K+ pump in cell membranes

Motors: - e.g. myosin (muscle), kinesin (cilia)

Hormones: - e.g. insulin, glucagon

Receptors: - e.g. rhodopsin (light receptor in retina)

Antibodies: -  e.g. immunoglobulins

Storage: - e.g. albumins in eggs and blood, caesin in milk

Blood clotting: - e.g. thrombin, fibrin

Lubrication: - e.g. glycoproteins in synovial fluid

Toxins: - e.g. diphtheria toxin

Antifreeze proteins: - e.g. antifreeze proteins in arctic spiders!

The list above is just a snapshot view of some the structural and functional roles proteins play in living organisms… and the following lessons we’ll take a look at how this super diverse group of biological molecules are made from amino acids, which form polypeptides though a series of stages resulting in the final 3D conformational shape of the protein with a unique structure and function.