Transport of oxygen and carbon dioxide

Question 1

Describe the Bohr Shift

Answer 1

• increased partial pressure of CO2 causes increased formation of carbonic acid
• this dissociates into H+ ions which increases the pH
• the increase in pH reduced the affinity of haemoglobin for oxygen
• more oxygen can be released as the tertiary structure of haemoglobin changes

Question 2

Why is it important that fetal haemoglobin is shifted to the left and up of maternal haemoglobin?

Answer 2

• fetus receives oxygen from the mother via the placenta
• fetal haemoglobin has a higher affinity for oxygen
• so it can bind to oxygen at lower partial pressures