Measurements of oxygen binding by whole human blood, at 37°C, at pH 7.4, and in the presence of 40 mm Hg of CO2 and normal physiological levels of BPG (5 mmol/L of cells), give the following:

a. From these data, construct a binding curve, and estimate the percent oxygen saturation of blood at (1) 100 mm Hg, the approximate partial pressure of O2 in the lungs, and (2) 30 mm Hg, the approximate partial pressure of O2 in venous blood.
b. Under these conditions, what percentage of the oxygen bound in the lungs is delivered to the tissues?
c. Using the data in Figure 7.27, repeat the calculation of part (b) if the pH drops to 6.8 in capillaries but goes back to 7.4 as CO2 is unloaded in the lungs.

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Po, (mm Hg) 10.6 19.5 27.4 37.5 50.4 77.3 92.3 % Saturation (= 100 × Y 10 30 50 70 85 96 98 .)