Question

Which of the following is incorrect about the transport of gases by blood?

• A. The oxygen dissociation curve is sigmoid and shifts to the right at high pCO₂, and low pH.
• B. Every 100 ml of oxygenated blood can deliver around 5 ml of O₂ to the tissues under normal physiological conditions.
• C. The major factor affecting the formation of carbamino-hemoglobin is low H⁺ concentration.
• D. Approximately 70% of carbon dioxide is carried as bicarbonates.

Answer 1

Answer: (C)

CO₂ is carried by hemoglobin as carbamino-hemoglobin (about 20-25 percent). This binding is related to the partial pressure of CO₂. pO₂ is a major factor that could affect this binding. When pCO₂ is high and pO₂ is low as in the tissues, more binding of carbon dioxide occurs whereas, when the pCO₂ is low and pO₂ is high as in the alveoli, dissociation takes place.