What structural features of erythrocytes are associated with their functions?

The structure of red blood cells is directly related to their functions. As you know, the main function of erythrocytes is transport (transport of oxygen and carbon dioxide), which is carried out at the expense of hemoglobin. Having a biconcave shape, erythrocytes increase the total surface, bring the inner contents of the cell closer to the surface, which means they are able to bind and transport oxygen or carbon dioxide as much as possible. Also, the absence of a nucleus in mature erythrocyte cells increases their surface.