Question

Questions 19-20

19. Which of the following factors INCREASES hemoglobin’s affinity for oxygen? [MARK ALL THAT APPLY]

a. decreased [H+ ] b. decreased temperature c. decreased PO2 d. decreased pH    e. increased PCO2

20. You discover a new mutation in the gene coding for carbonic anhydrase. You observe that patients with this mutation exhibit:

a. less buffering capacity of the blood

d. higher PCO2 levels in blood

b. less bicarbonate [HCO3-] concentration in blood

e. Hb has a lower affinity for O2 than normal

c. any of these could indicate a problem with carbonic anhydrase

Answer 1

19. The binding affinity of hemoglobin to oxygen drpends on factors such as partial pressure of oxygen, partial pressure of CO2, pH and temperature.
Increase in partial pressure of oxygen and increase in pH increase the binding capacity of hemoglobin to oxygen.
Decrease in partial pressure of CO2 and decrease in temperature also increases hemoglobin affinity for oxygen.
Decrease in H+ ions results in high pH which increases hemoglobin binding for oxygen.
So the correct option is a. decreased [H+ ] b. decreased temperature

20. Carbonic anhydrase is an enzyme found in RBC which helps in conversion pf CO2 to carbonic acid and bicarbonate ions. It helps regulate the blood pH and pCO2 levels in blood.
Low buffering capacity of the blood, high PCO2 levels in blood, low bicarbonate [HCO3-] concentration in blood and decreased affinity of Hb for O2 implies towards a problem with carbonic angydrase.
So the correct option is (c. ) any of these could indicate a problem with carbonic anhydrase