NEET2026BiologyChapterActual
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): At the tissue level, oxygen readily dissociates from oxyhaemoglobin. Reason (R): Actively metabolising tissues are characterised by low pO₂ , high pCO₂ , high H^+ concentration, and higher temperature. In the light of the above statements, choose the most appropriate answer from the options given b
Options
- ABoth (A) and (R) are correct but (R) is not the correct explanation of (A)
- B(A) is correct but (R) is incorrect
- C(A) is incorrect but (R) is correct
- DBoth (A) and (R) are correct and (R) is the correct explanation of (A)
Correct answer
D. Both (A) and (R) are correct and (R) is the correct explanation of (A)
Step-by-step solution
Assertion (A) is correct because at the tissue level, oxygen dissociates from oxyhaemoglobin to meet the oxygen demand of the cells. Reason (R) is correct because actively metabolising tissues continuously consume O₂ and release CO₂ , which results in low pO₂ and high pCO₂ . The accumulation of CO₂ and metabolic acids increases the H^+ concentration (lowering the pH), and the heat generated by cellular respiration raises the temperature. These conditions (low pO₂ , high pCO₂ , high H^+ concentration, and higher tem