Does anyone know the role of iron in the metabolism? I need three functions!

I know its use as making haemoglobin, the red substance in the blood. I had to Google, and found that iron

1. Transport and storage of oxygen.
2. Aid in energy production and cell diffusion.
3. Helps the immune and central nervous systems.

Iron: foods, benefits of, function of, iron absorption, types, iron in food (http://www.mamashealth.com/nutrition/iron.asp)

Hope it helped! :)