Question

Bilirubin and biliverdin are
A. Bile salts
B. Bile pigments
C. Enzymes
D. None of the above

Answer 1

Hint:- The action of biliverdin reductase on biliverdin, a green tetrapyrrole bile pigment that is also a result of heme catabolism, generates bilirubin. Bilirubin reverts to biliverdin again when oxidised. In addition to the demonstration of the strong antioxidant action of bilirubin, this cycle has led to the theory that the key physiological function of bilirubin is as a cellular antioxidant.

Complete answer:
Bilirubin (BR) is a yellow compound that exists in vertebrates within the usual catabolic pathway that breaks down heme. This catabolism is an important mechanism in the clearance of waste materials by the body resulting from the breakdown of ageing or dysfunctional red blood cells. Next, depending on the portion of the body in which the degradation happens, the haemoglobin is drained of the heme molecule, which then goes into separate porphyrin metabolism cycles.
The first major step in the catabolic process is the synthesis of heme biliverdin, after which the biliverdin reductase enzyme performs the second step, producing bilirubin from biliverdin. In bile and urine, bilirubin is excreted, and elevated levels can suggest some diseases. It is responsible for the bruises' yellow hue and the jaundice's yellow discoloration.
Although traditionally treated as a mere waste product of heme breakdown, there has been mounting evidence suggesting that biliverdin and other bile pigments have a physiological role in humans. Bile pigments such as biliverdin have essential antimutagenic and antioxidant properties and can also play a physiological role that is beneficial. Potent scavengers of hydroperoxyl radicals have been found to be biliverdin and bilirubin. The effects of polycyclic aromatic hydrocarbons, heterocyclic amines and oxidants, all of which are mutagens, have also been found to inhibit them.
From these discussions we can conclude that Bilirubin and biliverdin are bile pigments. Therefore the correct answer is option (B).

Note:- In the blood of people suffering from hepatic diseases, Biliverdin was found in abundance. Jaundice is caused by the deposition in the circulatory system and tissues of biliverdin or bilirubin (or both). Liver failure is characteristic of jaundiced skin and sclera (whites of the eyes).