Where is the building function of proteins carried out?

Proteins are the building blocks of the body. They play a vital role in the structure of tissues and organs. Protein promotes the growth of muscles, new skin, hair, bones, cartilage and blood. Hair and nails are mostly made from protein. The human body uses protein to build and repair tissue.

Structural proteins (fibrous proteins) provide the internal structure of the cell as part of its cytoskeleton or assist in the movement of cells. These include keratins, collagen and elastin.