Transport of Carbon Dioxide

Question 1

Name the three ways in which carbon dioxide is transported

Answer 1

In solution in the plasma (5%)
As the hydrogen carbonate ion, HCO3- (85%)
Bound to haemoglobin as carbamino-haemoglobin (10%)

Question 2

What substance catalyses the combination of carbon dioxide and water into carbonic acid?

Answer 2

Carbonic anhydrase

Question 3

What does carbonic acid dissociate into?

Answer 3

H+ ions and HCO3- ions

Question 4

When HCO3- diffuse out of the red blood cells into the plasma, what happens to balance the outflow of negative ions and maintain electrochemical neutrality?

Answer 4

Chloride ions diffuse into the red blood cells from the plasma (the chloride shift)

Question 5

What do H+ ions cause oxyhaemoglobin to dissociate into and what do the H+ ions then combine with to form what?

Answer 5

Dissociates into oxygen and haemoglobin and the H+ ions combine with the haemoglobin to form haemoglobinic acid so the pH of the blood doesn’t fall as the hydrogen ions are removed.