Structural Proteins

• Support

• Insects and spiders use silk fibers.• Keratin is the protein of hair, horns, feathers.

Storage Proteins

• Storage of amino acids

• Ovalbumin: protein of egg white – amino acid for developing embryo

• Plants have storage proteins in seeds

Transport Proteins

• Transport of other substances

• Haemoglobin, iron containing protein, transports oxygen

Hormonal proteins

• Coordination of an organisms activities

• Insulin – hormone secreted in pancreas – controls blood glucose levels

Receptor proteins

• Response of cell to chemical stimuli

• Receptors in nerve cell membrane detect chemical signals released by other nerve cells

Contractile proteins

• Movement

• Actin and myosin: movement of muscles• Other proteins used for movement of flagella

Defensive proteins

• Protection against disease

• Antibodies combat bacteria and viruses

Structural Proteins

• Support

• Insects and spiders use silk fibers.• Keratin is the protein of hair, horns, feathers.