Author Question: Why is the presence of carbonic anhydrase in RBCs so crucial for carbon dioxide transport? a. ... (Read 27 times)

xclash · **on:** Jul 16, 2018

Why is the presence of carbonic anhydrase in RBCs so crucial for carbon dioxide transport?

a. Forms H2CO3, which is the major buffer for carbon dioxide.
b. Drives the hydrolysis reaction that forms HCO3-.
c. Forms H2CO3, which is the way the ma-jority of carbon dioxide is transported.
d. Without its formation, carbon dioxide could not be excreted at the lungs.

Question 2

The largest percentage of carbon dioxide transported in the blood occurs as which of the follow-ing?

a. Carbamino-Hb
b. Carbonic acid (H2CO3)
c. HCO3
d. Physically dissolved carbon dioxide

eliasc0401 · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

ANS: B
Hydrolysis of carbon dioxide initially forms carbonic acid, which quickly ionizes into hydrogen and bicarbonate ions:
CO2 + H2O H2CO3 HCO3 + H+
However, the rate of this plasma hydrolysis reaction is extremely slow, producing minimal amounts of H+ and HCO3. This reaction is greatly enhanced by an enzyme catalyst called car-bonic anhydrase.

Answer to Question 2

ANS: C
Approximately 80 of the blood carbon dioxide is transported as bicarbonate.