Question

Assertion :More of oxygen is released from oxyhaemoglobin in a more active tissue than in a less active one. Reason: This is because partial pressure of carbon-dioxide is very low in an active tissue than in a less active one.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
• C. Assertion is correct but Reason is incorrect.
• D. Assertion is incorrect but Reason is incorrect.

Answer 1

The correct option is C Assertion is correct but Reason is incorrect.

Binding of oxygen with haemoglobin is primarily related to partial pressure of oxygen. Partial pressure of carbon dioxide, hydrogen ion concentration and temperature are the other factors, which can interfere with this binding. Oxygen dissociation curve is highly useful in studying the effect of factors like partial pressure of carbon dioxide, $H^{+}$ concentration, etc., on binding of oxygen with haemoglobin. In the alveoli, where there is high partial pressure of oxygen, low partial pressure of carbon dioxide, lesser proton concentration and lower temperature, the factors are all favourable for the formation of oxyhaemoglobin, whereas in the tissues, where low partial pressure of oxygen, high partial pressure of carbon dioxide, high $H^{+}$ concentration and higher temperature exist, the conditions are favourable for dissociation of oxygen from the oxyhaemoglobin. As, the $PC{O}_2$ in active tissue is high than less active tissue, more oxygen will be given to them.