Write a note on respiratory pigments.

Explanation

Haemoglobin Haemoglobin belongs to the class of conjugated protein. The iron containing pigment portion haem constitutes only 4% and the rest colourless protein of the histone class globin. Haemoglobin has a molecular weight of 68,000 and contains four atoms of iron, each of which can combine with a molecule of oxygen.
Methaemoglobin If the iron component of the haem moieties is in the ferric state, than the normal ferrous state, it is called methaemoglobin. Methaemoglobin does not bind `O_(2)` . Normally RBC contains less than 1% methaemoglobin .