Question

In the breakdown of hemoglobin, the globin chains __________.

are converted into bilirubin by macrophages

are broken down by macrophages into amino acids


are stored in various tissues


contribute to the color of feces


are converted into biliverdin by macrophages

Answer 1

In the breakdown of hemoglobin, the globin chains are broken down by macrophages into amino acids. Bilirubin, a byproduct of the breakdown of the heme portion of hemoglobin, contributes to the color of feces.

Step-by-step explanation:

The globin chains in the breakdown of hemoglobin are broken down by macrophages into amino acids. This process occurs when red blood cells (RBCs) reach the end of their lifespan and are phagocytized by macrophages in the reticuloendothelial system, mainly in the spleen, liver, and bone marrow. The globin chains are then metabolized into amino acids, which can be reused for protein synthesis.

In addition to the globin chains, the heme portion of hemoglobin is also broken down. The non-iron portion of heme is degraded into the waste product biliverdin, a green pigment, and then into bilirubin, a yellow pigment. Bilirubin is used by the liver in the manufacture of bile, which is released into the intestines to help emulsify dietary fats. In the large intestine, bacteria convert bilirubin into urobilinogen and then into stercobilin, which gives feces its typical brown color. It is then eliminated from the body in the feces.