Question

Differentiate between oxyhaemoglobin and carbaminohemoglobin with reference to their formation.

Answer 1

Hint: Oxyhaemoglobin is a bright red substance formed in the presence of oxygenated blood when hemoglobin combines with oxygen. Carbaminohemoglobin is formed when hemoglobin and carbon dioxide combine, and in this form 20% carbon dioxide exists in the blood.

Complete answer:
In this question we have to differentiate between oxyhaemoglobin and carbaminohemoglobin with reference to their formation.
So, what is Hemoglobin? Hemoglobin is a globular protein with four heme molecules held in it by intermolecular bonds.
When carbon dioxide and hemoglobin bind, a molecule forms which we call carbaminohemoglobin. Binding of carbon dioxide and hemoglobin is reversible. Therefore, when it reaches the lungs, this carbaminohemoglobin breaks and carbon dioxide can freely dissociate from the hemoglobin removed from the body by expiration. While, Oxygen from lungs diffuses into blood and binds with hemoglobin molecule which is packed into RBC.
At high concentrations of oxygen which is found in the lungs, oxygen molecules bind to the iron (II) ions of the heme molecules to form oxyhaemoglobin. One hemoglobin molecule carries four oxygen molecules. About 98.5% of the oxygen in blood is transported as oxyhaemoglobin. In tissues, oxygen is low, so the oxyhemoglobin dissociates to release oxygen.

Note: There are some other molecules of hemoglobin which have similar names like carboxyhemoglobin. It forms when carbon monoxide binds with hemoglobin. So, you should not be confused between carbaminohemoglobin, which is hemoglobin + carbon dioxide and carboxyhemoglobin, which is hemoglobin + carbon monoxide.