Question

What is the function of iron on a molecular level? Is it an electron acceptor or donor? Does it assist in forming covalent bonds? Is it present in certain enzymes like a vitamin?

Answer 1

• The function of iron on a molecular level is its role in the body by acting as a central atom of the heme group, which is a metal complex binding molecular oxygen in lungs and carrying it to all the cells and muscles in the body which needs the oxygen for performing their activities. It also plays a role in transporting carbon dioxide from the tissues to the lungs.
• Iron (III) is an "electron acceptor" as it acts as an oxidizing agent in chemical reactions. During some oxidation processes, iron acts as an electron acceptor.
• Iron cannot assist in forming covalent bonds because, as iron is a metal, metals cannot form covalent bonds due to their low ionization energies. But, metals like iron can form a special type of bonding called 'metallic bonding', which is different from ionic and covalent bonding and iron can form 6 metallic bonds.
• Iron is not present in all types of enzymes. Vitamin is a coenzyme and iron is a cofactor. Vitamins are found in foods and other natural sources but, iron is found in foods like red meat and iron becomes a part of haemoglobin in our body. So, some vitamins contains little or no amount of iron in them.

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