This 4-inch reproduction of human Hemoglobin is 18 Million times larger than actual 55 Angstrom in diameter protein. Hemoglobin is the protein inside red blood cells that transports oxygen molecules throughout the body. This model is made from x-ray crystallography data of Oxygengated Hemoglobin (PDB ID: 1HH0). Each spherical unit on the model represents the position of a single atom. Colored in red are the protein’s HEME Groups, disk-like structures with an Iron atom core. It is to this Iron atom core that binds O2 molecules (Blue) bind. Just like magenets are attracted to iron nails, so too are O2 molecues attracted to Heme Groups. This is a fun model to introduce molecular biology to your friends, children and colleagues.