The most prominent of these (and historically the first) is the representation theory of groups, in which elements of a group are represented by invertible matrices in such a way that the group operation is matrix multiplication.
hemoglobin is able to perform this function due to its ability to reversibly bind to oxygen. inside oxygen rich areas of the lungs, hemoglobin picks up oxygen molecules, then it transports the oxygen via red blood cells to bodys tissue, once hemoglobin reached the oxygen poor area of the tissues it releases the oxygen.
Hemoglobin binds oxygen by rusting on the atomic level. The hemoglobin molecule in red blood cells is what the U.S. Department of Energy's Office of Science calls a metalloprotein.. That is, it is a protein that incorporates some metal, iron in this case, into its structure.