Final answer:
Each hemoglobin molecule contains four globin proteins, and each can bind to one molecule of heme. Therefore, a single chain globin can bind and transport up to 1.2 billion oxygen molecules.
Step-by-step explanation:
Each hemoglobin molecule contains four globin proteins, with each globin protein binding to a molecule of heme. Each iron ion in the heme can bind to one oxygen molecule. Therefore, each hemoglobin molecule can transport four oxygen molecules.
An individual erythrocyte, or red blood cell, may contain about 300 million hemoglobin molecules. So, a single chain globin can bind and transport up to 1.2 billion oxygen molecules, as each hemoglobin molecule can carry four oxygen molecules.
Overall, the oxygen binding capacity of hemoglobin is essential for the transport of oxygen throughout the body.