are made of amino acids (CHON) structural and working substance in all cells not just muscle cells

Contain carbon, hydrogen, oxygen (like carbohydrates and fats)

CANNOT be produced by the body

–MUST be obtained in diet

CAN be produced by the body

–NO NEED to be obtained in diet

–Aspartic acid

–Glutamic acid

–Histidine

–Lysine

–Arginine

Leucine, lysine

Histidine, Methionine, Valine

Isoleucine, Threonine, Tyrosine, Phenylalanine

have two amino acids bonded together.