IRON STORAGE IN THE BODYSolutionIron is necessary for oxygen

IRON STORAGE IN THE BODY

Solution

Iron is necessary for oxygen transport in the blood. iron is the central atom of the heme group, a metal complex that binds molecular oxygen in the lungs and carries it to all of the other cells in the body that need oxygen to perform their activities.

Because iron plays such a crucial role in the body, it is important for us to maintain an adequate supply of iron to form hemoglobin and the other molecules in the body that depend on iron to function properly.

Bleeding, particularly menstrual bleeding in women, contributes to further loss of iron from the body. To compensate for these losses and to maintain an adequate supply of iron, we should consume approximately 18 mg of iron daily. Good dietary sources of iron include red meat, liver, egg yolk, beans, nuts, and fortified cereals.

When the body\'s supply of available iron is too low, a condition known as iron deficiency results. It is also possible to have too much iron deposited in the body tissues. This condition is known as iron overload.

Iron is stored, mostly in the liver, as ferritin or hemosiderin. Ferritin is the key to this important control of the amount of iron available to the body. Ferritin is a protein that stores iron and releases it in a controlled fashion. Ferritin is a protein with a capacity of about 4500 iron (III) ions per protein molecule. If the capacity for storage of iron in ferritin is exceeded, a complex of iron with phosphate and hydroxide forms. This is called hemosiderin; it is physiologically available. Ferritin has the shape of a hollow sphere. Inside the sphere, iron is stored in the Fe(III) oxidation state. It is incorporated in the mineral ferrihydrite which is attached to the inner wall of the sphere. To release iron when the body needs it, the iron must be changed from the Fe(III) to the Fe(II) oxidation state. Then, the iron leaves through channels in the spherical structure. Thus, the structure of ferritin is extremely important for the protein\'s ability to store and release iron in a controlled fashion.