cells within human brain tissues. Biosynthesis of magnetite particles in vertebrates like mammals is implied to be similar to that observed in bacterial cells, although no evidence is provided. The difference between bacterial magnetosomes and human magnetosomes appears to be the number of magnetite particles synthesized per cell, the clustering of those particles within each respective organism, and the purpose of each magnetosome. A species of magnetosomic bacterial cell may have 20 magnetic particles arranged linearly in an organelle for each member of the species. A human may have between 1000 and 10000 magnetic particles arranged in a cluster within an organelle with only one cell in 5000 having said organelle. Finally, the human magnetosomic organelle has an unknown function that does not involve detecting the earth's magnetic field. Formation Magnetotactic bacteria use a process known as biomineralization to exert an incredible degree of control on the formation of the mineral crystals within the magnetosomes. The process of biomineralization allows the MTB to control the shape and size along with the alignment of each individual magnetite crystal. These specific magnetite crystals are all identical within a species but between species they can vary in size, structure, formation, amount, but not purpose. They are always used to follow geomagnetic pulls to more agreeable climates for the bacteria. These magnetite crystals are contained within an organelle envelope. This envelope is referred to as a magnetosome. Within the organelle there can either ferrimagnetic crystals of magnetite () or the iron sulfide greigite (). Recently there have been a few other magnetic compounds found but these are far less common and do not change the purpose of the organelle. Around twenty proteins have been found in magnetotactic bacteria that are specifically used for the creation of magnetosomes. These proteins are responsible for the control of vesicle formation, magnetosome ion transport, and the crystallization of the magnetites and their arrangement with in the particular vesicle. The arrangement of the magnetites is critical because individually they are not very strong, but when linked in an ordered chain they increase significantly in strength. There is another set of acidic proteins in the magnetosome that are used to create a link between the vesicle and the cytoskeletal structure in the cell to help the magnetosome hold shape. Magnetites Magnetite crystals are encased in the magnetosome giving the MTB its magnetic properties. These crystals can either be made of