Transport of O₂ and CO₂ in Blood — NEET Biology
📚 Practice ConceptOxygen is transported mainly as oxyhaemoglobin. In the alveoli where pO₂ is higher, O₂ gets bound to haemoglobin which is easily dissociated at the tissues where pO₂ is low and pCO₂ and H⁺ concentration are high. Nearly 70 per cent of carbon dioxide is transported as bicarbonate (HCO₃⁻) with the help of the enzyme carbonic anhydrase. 20-25 per cent of carbon dioxide is carried by haemoglobin as carbamino-haemoglobin. In the tissues where pCO₂ is high, it gets bound to blood whereas in the alveoli where pCO₂ is low and pO₂ is high, it gets removed from the blood.
Which of the above statements are correct? S1: Approximately 70% of carbon dioxide is transported from tissues to alveoli in the form of bicarbonate ions, primarily generated in the plasma. S2: Carbonic anhydrase is an enzyme found in high concentration in RBCs and also in minute quantities in the plasma. S3: At the tissue site, high pCO2 and low pO2 favor the formation of carbamino-haemoglobin. S4: The reaction CO2 + H2O → H2CO3 occurs spontaneously in tissues without enzymatic catalysis at a significant rate. S5: Every 100 ml of deoxygenated blood delivers approximately 4 ml of CO2 to the alveoli.
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