Final answer:
Each hemoglobin molecule can bind to four oxygen molecules. It also can bind to carbon dioxide using a different mechanism, and by doing so, it increases the solubility of oxygen in the blood. Hence, all of the statements about hemoglobin are true.
Step-by-step explanation:
Which statements about hemoglobin are true? Regarding the relationship between hemoglobin and oxygen, several key points are noteworthy:
- Each hemoglobin molecule can bind up to four oxygen molecules because it contains four iron-containing heme groups.
- Hemoglobin can indeed bind to carbon dioxide, though the mechanism is different from its oxygen-binding function.
- By binding oxygen, hemoglobin significantly increases the solubility of oxygen in blood.
Therefore, the correct answer to the student's question would be (e) All of the above are true.