Question

Carbon monoxide is a pollutant because
A. It reacts with $O_2$
B. It inhibits glycolysis
C. Reacts with haemoglobin
D. Makes nervous system inactive

Answer 1

Hint: We already know that Carbon monoxide with chemical formula CO is a colourless, tasteless, odourless and a very toxic pollutant which is produced by the incomplete combustion of carbon containing fuels and it has the ability to form a complex with haemoglobin.

Complete Answer:
- When we inhale the carbon monoxide, it immediately crosses the alveolar epithelium to reach the blood and in blood it binds with the haemoglobin at the same site where oxygen binds. $CO$ binds with haemoglobin with an affinity 200 times more than the oxygen.
- After binding to the haemoglobin, it forms a very stable complex called Carboxyhemoglobin (COHb) which is formed more readily than the oxyhaemoglobin complex $(Hb{O_2})$.
- This complex is unable to carry and transport the oxygen across the body tissues and results in shifting the dissociation curve to the left indicating the inhibition of release of oxygen. This causes the oxygen tension in the body and eventually leads to death of the individual. Hence, the third statement is correct.
- Carbon monoxide is complex with haemoglobin and inhibits the release of oxygen, it results in making the nervous system inactive because not sufficient oxygen is supplied to the brain. Thus this statement is also true.

Therefore the correct answer is (C) and (D).

Note: Pollution is the effect of undesirable changes in our surroundings that have harmful effects on plants, animals and human beings. Pollutants include solid, liquid or gaseous substances present in greater than natural abundance, produced due to human activity, which have a determined effect on our environment.