Question

Haemoglobin has highest affinity for

(a) oxygen 

(b) carbon dioxide

(c) carbon monoxide 

(d) nitrogen

Answer 1

(c) carbon monoxide 

Carbon monoxide (CO) combines with haemoglobin to produce carboxyhaemoglobin, which occupy the space in haemoglobin that normally carries oxygen. Haemoglobin has 250 times more affinity to carbon monoxide as compared to oxygen.

Answer 2

(c) carbon monoxide 

Hemoglobin in humans has a very high affinity for carbon monoxide, forming carboxy hemoglobin which is a very bright red in color. Carbon monoxide is thus problematic for humans because it has affinity higher than that of oxygen.