The ionic form of iron (Fe2+ and Fe3+) can damage the molecules present in the cell and in the blood. Protective protein escorts namely transferring and ferritin bind to the ionic form of iron during its transport and storage.
In small intestine during absorption, the ionic form of iron is actively transported into the mucosa of intestinal lining. Once inside the mucosal cells, it binds to the ferritin protein. These iron-ferritin complexes of mucosal cells are the stored form of iron.
Following its active absorption, the binding of iron to ferritin in mucosal cells of intestinal lining is referred to as the mucosal iron barrier. When needed, a few of the stored iron is passed into the portal blood while the major proportion of the stored iron is released from the barrier only when the epithelial cells are sloughed off.
for a substance to be a mineral it must be a naturally occurring inorganic crystalline solid that has a characteristics chemical composition and Crystal structure
It is a mode of natural selection where an extreme phenotype is favored by the other phenotypes causing the allele frequency to shift over time in the direction of that phenotype
