Component 3.2 - Transport Of CO2

Question 1

How is CO2 transported in the blood?

Answer 1

As the hydrogen carbonate ion and carbaminohaemoglobin

Question 2

Describe the process of how HCO3- ions are produced from carbon dioxide

Answer 2

1) Carbon dioxide in the blood diffuses into the red blood cell
2) Carbonic anhydrase catalysed the combination of carbon dioxide with water, making carbonic acid
3) Carbonic acid dissociates into H+ and HCO3- ions
4) HCO3- ions diffuse out of the red blood cell into the plasma

Question 3

How does the red blood cell remain at a neutral PH after HCO3 ions diffuse out?

Answer 3

1) To balance the outflow of negative ions and maintain electrochemical neutrality, chloride ions (chloride shift) diffuse into the red blood cell from the plasma
2) H+ ions cause oxyhaemoglobin to dissociate into oxygen and haemoglobin. The H+ ions combined with haemoglobin to make haemoglobinic acid. This removes hydrogen ions and so the PH of the red blood cell does not fall
3) Oxygen diffuses out of the red blood cell into the plasma

Question 4

How does haemoglobin help keep PH constant?

Answer 4

It buffers the blood by removing hydrogen ions which prevents the PH from falling