MICROANATOMY

Detailed explanation-1: -The hemoglobin molecule has four binding sites for oxygen molecules: the iron atoms in the four heme groups. Thus, each Hb tetramer can bind four oxygen molecules. From the molecular weight of Hb, one can calculate that 1 g of Hb can combine with 1.39 ml of oxygen.

Detailed explanation-2: -It is the millions of iron-containing haemoglobin proteins that make blood red. Molecules with more oxygen bound to them are brighter red. When the red blood cells reach tissues that need oxygen, the oxygen is released from the haemoglobin and diffuses into the cells where it is used to make energy.