How many oxygen molecules can one hemoglobin molecule bind?

How many oxygen molecules can one hemoglobin molecule bind?

• A. 2
• B. 3
• C. 4
• D. 5

Answer: (C)

One hemoglobin molecule can bind four oxygen molecules. This capacity is due to the structure of hemoglobin, which is a tetramer composed of four polypeptide subunits. Each subunit has a heme group, which contains an iron atom capable of forming a reversible bond with an oxygen molecule. When oxygen binds to one of the heme groups, it induces a conformational change in the hemoglobin molecule that increases the affinity of the remaining heme groups for oxygen. As a result, hemoglobin can effectively transport oxygen from the lungs to the tissues, making its ability to bind four oxygen molecules integral to its role in the body.

One hemoglobin molecule can bind four oxygen molecules. This capacity is due to the structure of hemoglobin, which is a tetramer composed of four polypeptide subunits. Each subunit has a heme group, which contains an iron atom capable of forming a reversible bond with an oxygen molecule. When oxygen binds to one of the heme groups, it induces a conformational change in the hemoglobin molecule that increases the affinity of the remaining heme groups for oxygen. As a result, hemoglobin can effectively transport oxygen from the lungs to the tissues, making its ability to bind four oxygen molecules integral to its role in the body.