Question

Which mineral is part of hemoglobin?

• A. Calcium
• B. Iron
• C. Zinc
• D. Sodium

Hint:

The red color of blood is due to the interaction of iron with oxygen in the heme groups of hemoglobin.
Without iron, the body cannot manufacture hemoglobin, leading to anemia.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks to identify the specific mineral that forms an integral structural component of hemoglobin, the oxygen-carrying protein in red blood cells.

Step 2: Key Concepts and Approach:
Hemoglobin is a metalloprotein containing globin proteins and heme groups.
The functional capacity of hemoglobin to bind and transport oxygen depends on the transition metal ion coordinated at its center.

Step 3: Detailed Explanation:

• Structure of Hemoglobin: Hemoglobin is made of four polypeptide globin chains, each containing a non-protein heme group.

• Role of Iron: At the center of each heme group is a single iron atom in the ferrous ($Fe^{2+}$) oxidation state.

• Oxygen Binding: This iron atom has six coordination positions.
Four are bound to nitrogen atoms of the porphyrin ring, one is bound to a histidine residue of the globin protein, and the sixth is available for reversible binding with an oxygen ($O_2$) molecule.

• Deficiency Outcome: A lack of dietary iron impairs the synthesis of heme, leading to iron-deficiency anemia, characterized by microcytic, hypochromic red blood cells and reduced oxygen transport capacity.

Step 4: Final Answer:
The mineral that is part of hemoglobin is iron.