Question

which of the following is accurate regarding the transport of O2 and CO2?

a) most O2 is transported in the erythrocytes

b) most CO2 is transported in the erythrocytes

c) most CO2 is transported in the plasma

d) both: most O2 is transported in the erythrocytes AND most CO2 is transported in the erythrocytes

e) both: most O2 is transported in the erythrocytes AND most CO2 is transported in the plasma

Answer 1

e) both: most O2 is transported in the erythrocytes AND most CO2 is transported in the plasma.

EXPLANATION:

Although oxygen dissolves in blood, only a small amount of oxygen is transported this way. Only 1.5 percent of oxygen in the blood is dissolved directly into the blood itself. Most oxygen—98.5 percent—is bound to a protein called hemoglobin in the erythrocyte and carried to the tissues.

60% of all CO2 is transported through production of HCO3– ions in the red blood cell. CO2 diffuses into the red blood cells and is converted to H+ and HCO3– by an enzyme called carbonic anhydrase. This HCO3– is transported back into the blood via a chloride-bicarbonate exchanger (aka anion exchanger/AE). The HCO3– can now act as a buffer against any hydrogen in the blood plasma.