NEETZoologyBreathing and Exchange of Gases
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In the tissues, the oxygen dissociation curve shifts to the right, promoting the dissociation of oxygen from oxyhaemoglobin. Reason (R): High pCO₂ , high H^+ concentration, and higher temperature in the tissues decrease the affinity of haemoglobin for oxygen. In the light of the above statements, c
Options
- ABoth Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- BBoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- CAssertion (A) is true but Reason (R) is false.
- DAssertion (A) is false but Reason (R) is true.
Correct answer
B. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
Step-by-step solution
The oxygen dissociation curve represents the percentage saturation of haemoglobin with oxygen at different partial pressures of oxygen ( pO₂ ). In the tissues, metabolic activities consume oxygen and produce carbon dioxide, leading to low pO₂ and high pCO₂ . The high pCO₂ leads to an increase in H^+ concentration (lower pH). Additionally, the temperature in active tissues is slightly higher. According to NCERT, these conditions (high pCO₂ , high H^+ concentration, and higher temperature) decrease the affinity of ha