Aminio acids are buiding blocks
The smallest building blocks of protein are amino acids. There are 21 different amino acids, of which 8 as a structural building materials are essential (vital), these 8 essential amino acids must be supplied regularly through food. Our body if necessary to connect the remaining 13 amino acids by converting fatty acids itself. In addition to this, necessary for the development of protein, 21 amino acids, there are still some "non-proteinogenic" amino acids. These have no meaning for the protein synthesis, but nevertheless important biological function. Taurine or creatine for example belong to this group. Are essential amino acids: L-isoleucine, L-leucine, L-lysine, L-methionine, L-phenylalanine, L-threonine, L-tryptophan, L-valine. Are semi essential amino acids: L-arginine and L-histidine.