Amino acids are arranged like pearls in a chain. The amino acid chains are produced at the protein factories according to special blueprints.

Very small proteins are comprised of only 10 building blocks; very large ones can be made up of several thousand amino acids. The amino acids are linked in different combinations, forming chains of 40 to 400 protein building blocks.

Significant are the kind of building block and the sequence in which the building blocks are linked together, as each amino acid bestows certain characteristics on the protein, which are important for its mode of functioning. 

They give, so to speak, each protein a chemical "personality." This is why some proteins prefer watery environments, others oily ones such as the cell membrane.

For example, the shape of a protein depends on the kind and sequence of the amino acids: some proteins form long, screw-shaped chains. Others have round or twisted shapes, such as the protein in the red blood corpuscles which transports oxygen.

The "blueprint" for the precise sequence of the amino acids is laid down in the genes.