Describe the role of red blood cells in transporting oxygen around the body.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Red blood cells contain haemoglobin, which binds oxygen to form oxyhaemoglobin in the lungs. Oxyhaemoglobin then carries the oxygen through the bloodstream to body tissues, where it releases the oxygen as haemoglobin.
Red blood cells lack a nucleus, giving them extra space to store haemoglobin and maximise oxygen transport.
Red blood cells lack a nucleus, giving them extra space to store haemoglobin and maximise oxygen transport.
Examiner tips
- Use the term "haemoglobin" and "oxyhaemoglobin". Show the sequence: lungs → binding → transport → release. Mention the lack of a nucleus as a structural advantage.
- common_mistakes
- :
- Confusing haemoglobin with myoglobin. Forgetting to state that the cells lack a nucleus. Using the wrong spelling of haemoglobin/oxyhaemoglobin.
Mark scheme (4 marks)
- Red blood cells contain haemoglobin
- Haemoglobin combines with oxygen (to form oxyhaemoglobin) in the lungs
- Oxyhaemoglobin releases / splits back into haemoglobin and oxygen at the body tissues / organs
- Red blood cells have no nucleus, allowing more space to carry haemoglobin / oxygen
Key terms in this question
Related
- All WJEC GCSE Biology (Wales) revision notes →
- How to answer a "Describe" question →
- Decode the mark scheme abbreviations →