One gram of hemoglobin can bind approximately how many milliliters of oxygen?

One gram of hemoglobin can bind approximately how many milliliters of oxygen?

• A. 0.5 mL
• B. 1.0 mL
• C. 1.34 mL
• D. 2.0 mL

Answer: (C)

Oxygen-binding capacity per gram of hemoglobin is determined by how much O2 each gram of Hb can carry when fully saturated. Each hemoglobin molecule has four heme groups, so it can bind four O2 molecules. Hemoglobin has a molecular weight of about 64,500 g/mol, so 1 g of Hb is roughly 1/64,500 of a mole of Hb. Multiply by four O2 per Hb, and you get about 6.2 × 10^-5 moles of O2 per gram of Hb. Converting moles of gas to volume at standard conditions (1 mole = 22.4 L) gives roughly 0.0014 L, or about 1.34 mL of O2 per gram of Hb. This is the standard value used for fully saturated Hb. Hence the correct amount is about 1.34 mL per gram.

Oxygen-binding capacity per gram of hemoglobin is determined by how much O2 each gram of Hb can carry when fully saturated. Each hemoglobin molecule has four heme groups, so it can bind four O2 molecules. Hemoglobin has a molecular weight of about 64,500 g/mol, so 1 g of Hb is roughly 1/64,500 of a mole of Hb. Multiply by four O2 per Hb, and you get about 6.2 × 10^-5 moles of O2 per gram of Hb. Converting moles of gas to volume at standard conditions (1 mole = 22.4 L) gives roughly 0.0014 L, or about 1.34 mL of O2 per gram of Hb. This is the standard value used for fully saturated Hb. Hence the correct amount is about 1.34 mL per gram.