Explain why red blood cells are well adapted for 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 and carries it to tissues.
Their biconcave shape gives a large surface area for oxygen to diffuse in and out.
They are anucleate, so the cell volume is largely occupied by haemoglobin, increasing oxygen capacity.
Their biconcave shape gives a large surface area for oxygen to diffuse in and out.
They are anucleate, so the cell volume is largely occupied by haemoglobin, increasing oxygen capacity.
Examiner tips
- Use the word "binds" to show interaction with oxygen. Mention both the shape and lack of nucleus as adaptations. Keep the answer concise and use the exact terminology (haemoglobin, anucleate).
Common mistakes
- Forgetting to mention the biconcave shape or the lack of a nucleus. Using vague terms like "good for oxygen" without explaining the mechanism. Including irrelevant details such as blood pressure or heart rate.
Mark scheme (4 marks)
- Red blood cells contain haemoglobin
- Haemoglobin binds to / carries oxygen (allowing oxygen to be transported to tissues)
- Red blood cells have a biconcave shape, giving a large surface area (for oxygen absorption)
- Red blood cells have no nucleus (are anucleate), leaving more space for haemoglobin
Related
- All Edexcel GCSE Biology (1BI0) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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