At the gas exchange surface the pH of blood is relatively high due to the low concentration of carbon dioxide. The haemoglobin can load oxygen readily.Oxygen is transported bound to haemoglobin to the respiring tissues where it is needed for respiration.In the tissues carbon dioxide is produced by respiring cells. The carbon dioxide produced by respiring tissues lowers the pH and lowers the affinity of haemoglobin for oxygen. Oxygen is released.This ensures that the haemoglobin is loaded with oxygen at the lungs and unloaded at respiring tissue where oxygen is needed.In humans, blood leaving the lungs is about 97% saturated with oxygen.Blood returning to the lungs is about 75% saturated with oxygen.
Transport of Oxygen
Read the text
Read the text and highlight anything you think is important. When you go on, the text is hidden and you answer from memory.
Specification: AQA Biology (7401), AS-level, 3.3.4.1 Mass transport in animals. Topic: Mass Transport in Animals.
Key terms in this lesson
- haemoglobin
- A globular, quaternary protein in red blood cells, made of four polypeptide chains each with a haem group, that binds and transports oxygen.
More in Mass Transport in Animals
- Loading and Unloading Oxygen
- Different Types of Haemoglobin
- Oxygen Dissociation Curve
- Effect of Carbon Dioxide
- Lugworm
- Llama
- Fetal Haemoglobin
- Myoglobin
All 27 lessons in Mass Transport in Animals · All AQA AS-level Biology topics