Question

The hemoglobin-O₂ dissociation curve is shifted to the left:

    a. by an increase in PCO₂

  b. causing an increase in the affinity for O₂

    c. by a decrease in pH

    d. by an increase in temperature

    e. by an increase in hemoglobin concentration

Answer 1

b. causing an increase in the affinity for O2  c. by a decrease in pH

The increase in PCO2 decreases the H+ ion concentartion cause high pH shifts the curve to right because it stabilizes the deoxyhemoglobin in T state .T state has lower affinity for oxygen than R state,thus hemoglobin binding reduced with oxygen. The decreasing pH means increases the acidity or more H+ ion concentration causes more hemoglobin binding to the oxygen and shift to left. Increasing the temperature ,shifts the curev right ,because at high temperatire oxygen saturation decreases due to denaturation of bond between iron of hemoglobin and oxygen.