List and explain the 5 functions of proteins?

1) They serve as enzymatic catalysts, are used as

transport molecules (hemoglobin transports oxygen) and storage molecules (iron is stored

in the liver as a complex with the protein ferritin)

2) they are used in movement (actin, myosin)

3) they are needed for mechanical support (skin and

bone contain collagen-a fibrous protein)

4) they mediate cell responses (rhodopsin is a

protein in the eye which is used for vision)

5) antibody proteins are needed for immune

protection; control of growth and cell differentiation uses proteins (hormones).