Transporting Carbon Dioxide Flashcards
What is carbonic anhydrase?
The enzyme that catalyses the reaction between water and carbon dioxide.
What is the chloride shift?
The movement of chloride ions into erythrocytes to balance the charge as hydrogen carbonate ions leave the cell.
What is the Bohr effect?
The effect that extra carbon dioxide has on the haemoglobin, explaining the release of more oxygen.
What is haemoglobinic acid?
The compound formed by the buffering action of haemoglobin as it combines with excess hydrogen ions.
What are the 3 ways in which carbon dioxide is transported?
5% dissolved directly into the blood plasma.
10% is combined directly with haemoglobin to form a compound called carbaminohaemoglobin.
85% transported in the form of hydrogencarbonate ions .
When carbon dioxide combines with red blood cells what does it create?
A weak acid called carbonic acid. In the RBD the CO2 combines with H2O to form this acid. Catalysed by the enzyme carbonic anhydrase.
Changes in pH from the hydrogen ions affects the tertiary structure of the haemoglobin. What happens because of this?
It reduces the affinity of the haemoglobin to oxygen.
What is release when carbonic acid dissociates?
Hydrogen ions and hydrogencarbonate ions.
What happens when the hydrogencarbonate ions diffuse out of the red blood cell?
Chloride ions move into the RBC to maintain the pH.
How does haemoglobin act as a buffer to prevent the change in pH by the hydrogen ions?
The hydrogen ions are taken out of solution by associating with the haemoglobin to produce haemoglobinic acid.
When the partial pressure of CO2 is high which way does the association curve shift?
To the right.
If the partial pressure of oxygen is high and the partial pressure of CO2 is low which way doe the association curve shift?
To the left.
