Final answer:
Each gram of fully saturated hemoglobin can carry about 1.34 ml of oxygen, as each hemoglobin molecule has four heme units capable of binding one oxygen molecule each.
Step-by-step explanation:
When fully saturated, each gram of hemoglobin can carry approximately 1.34 ml of oxygen. This is because each iron ion in the heme of hemoglobin can bind to one oxygen molecule, and since each hemoglobin molecule is composed of four such heme units, it can therefore transport four oxygen molecules. Given that the molar mass of hemoglobin is about 64,500 grams per mole and each mole can bind approximately 1.34 ml of O₂, we end up with approximately 1.34 ml O₂ per gram of hemoglobin when it's fully saturated.