NEET Biology Breathing And Exchange Of Gases Based Practice Questions & Answers with Viewers Discussion and Detailed Explanation

Answer: (a)

Oxygen-haemoglobin dissociation curve demonstrates a progressive increase in the percentage of haemoglobin bound to oxygen as blood $pO_{2}$ increases which is called percent saturation of haemoglobin. The total quantity of oxygen bound to haemoglobin in normal systemic arterial blood, which is 97 percent saturated, is about 19.4 milliliters per 100 milliliters of blood. While passing through the tissue capillaries, this amount is reduced, on average, to 14.4 milliliters (p$O_{2}$ of 40 mm Hg, 75 percent saturated 14.4 millititers (p$O_{2}$ of 40 mm Hg, 75 percent saturated haemoglobin). Thus, under normal condition,s about 5 milliliters of oxygen are transported from the lungs to the tissues by each 100 milliliters of blood.