Question

Which statement about CO₂ is NOT correct? (0.35 pt) a) CO₂ binds to the same binding site on hemoglobin as O₂. b) CO₂ is more soluble in plasma than O₂ . c) P CO₂ in arterial plasma is lower than P O₂ in arterial plasma. d) P CO₂ in the peripheral tissues is higher than P O₂ in the peripheral tissues. e) All of the above are correct

Answer 1

The incorrect statement about CO₂ is that it binds to the same site on hemoglobin as O₂. CO₂ actually binds to a different part of the hemoglobin molecule to form carbaminohemoglobin.

Step-by-step explanation:

The statement about CO₂ that is NOT correct is 'a) CO₂ binds to the same binding site on hemoglobin as O₂.' Oxygen (O₂) binds to the iron in the heme group of hemoglobin, while carbon dioxide (CO₂) mostly binds to the amino groups of the globin portion of the hemoglobin molecule, a process forming carbaminohemoglobin. This binding is a different mechanism than the one through which oxygen binds. Also, the solubility and partial pressures of CO₂ and O₂ differ, with CO₂ being more soluble in plasma than O₂, and the partial pressure of CO₂ (P CO₂) being lower in arterial plasma than the partial pressure of oxygen (P O₂).

Additionally, P CO₂ is higher in the peripheral tissues, as CO₂ is produced as a byproduct of metabolism.

The dissolution in blood is another way through which CO₂ is transported, but a significant amount also binds to hemoglobin as carbaminohemoglobin.