Acting in a coherent fashion, the red blood cells play a more important role in life processes than is commonly known.
The red blood cells’ unique, remarkable role in oxygen and carbon dioxide transport sharply distinguishes them from the body’s other cells. So do their anaerobic energy metabolism, peculiar biconcave shape, 120-day life cycle (with 2,000,000 new RBCs formed every second), iron content, and extremely high hemoglobin content (roughly 270 million hemoglobin molecules are packed into each one of 25 trillion RBCs). While their counterparts in many vertebrates and invertebrates retain the nuclei and organelles that mammalian RBCs eject in the course of maturation, the erythrocyte group in general exhibits certain “prokaryotoid” characteristics,
