Question

Which hemoglobin component is recovered for reuse following red blood cell destruction? a. heme c. iron b. globin d. Both b and c are correct.

Short answer

Option d. Both b (globin) and c (iron) are correct.

Step-by-step solution

Understanding hemoglobin and red blood cell destruction.

Hemoglobin is a protein complex found in red blood cells, responsible for carrying oxygen from the lungs to the body's tissues and exchanging it for carbon dioxide. Hemoglobin consists of four subunits, each containing a heme group and a globin chain. The heme group consists of a porphyrin ring surrounding an iron ion, which binds oxygen. The globin chains are proteins that support the structure of the molecule. During the breakdown of red blood cells (RBCs), the various components of hemoglobin are separated and processed differently.

Analyzing the fate of heme during RBC destruction

When red blood cells are destroyed, heme is released from the hemoglobin molecule. It is then broken down via complex enzymatic reactions into a substance called biliverdin, which is subsequently converted into bilirubin. Bilirubin is then transported to the liver to be metabolized and excreted as bile. Thus, heme is not reused in the body.

Analyzing the fate of globin during RBC destruction

Globin is also released from the hemoglobin molecule during red blood cell destruction. Globin chains are then broken down into their constituent amino acids, which can be reused by the body to generate new proteins, including new globin chains for hemoglobin synthesis.

Analyzing the fate of iron during RBC destruction

Iron ions are released from the heme group during red blood cell destruction. Instead of being excreted, the iron is conserved and reused by the body. It is either stored in specialized proteins, such as ferritin or hemosiderin, or transported by transferrin to be used for the synthesis of new heme groups and other iron-dependent processes.

Conclusion

Based on the analysis of heme, globin, and iron during red blood cell destruction, we can conclude that globin and iron are both recovered for reuse in the body. Therefore, the correct answer is option d. Both b (globin) and c (iron) are correct.