chapter  4
chapter four
Pages 10

The function of red blood cells is to transport oxygen to tissues. This is accomplished by the intracellular protein

hemoglobin

. The quaternary hemoglobin protein is composed of two

α

and two

β

subunits. Each of the subunits contains a central iron containing protein called a

heme

protein. It is the iron atom in the heme protein that binds to molecular oxygen. As a result of the four iron-containing heme groups, each molecule of hemoglobin can carry four atoms of oxygen.