Link red blood cells with oxygen transport
Connect haemoglobin and the mature mammalian cell model with a specialised role.
Exam scope and assessment notes
Core and Extended · Biology 0970, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked; human subject-teacher review, supervised practical competence and cumulative assessment remain pending. Cambridge states that IGCSE 0970 has the same subject content as IGCSE 0610, with 9–1 grading. This StudyForA pathway maps the 2026–2028 syllabus only. This 9–1 graded qualification is available only in a limited number of administrative zones. Confirm that your centre can enter you for this code and exam series with Cambridge International. Cambridge has published a separate syllabus for 2029. StudyForA has not reconciled that version yet; this page supports exams in 2026, 2027 and 2028 only.
Before you begin
- Recall the distinction between plant, animal and bacterial cells. Read the supplied evidence before drawing a conclusion.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What is the specified red-blood-cell role?
What you will learn
- State the oxygen-transport function.
- Explain why a specialised animal cell can lack a nucleus.
An oxygen-carrying cell
Red blood cells transport oxygen using haemoglobin. In mammals, a mature red blood cell has a biconcave disc shape, a membrane and cytoplasm containing haemoglobin, but no nucleus. This leaves space for haemoglobin and is an exception to the typical animal-cell drawing.
The biconcave shape provides a large surface relative to volume and a short path to the interior; flexibility helps passage through narrow vessels. A red blood cell is not a hollow tube and does not pump blood: the heart provides the pumping action.
Qualify the model
The missing nucleus is a feature of mature mammalian red blood cells. It is not a rule for every animal cell or for every vertebrate red blood cell. The disc sketch is schematic; the pale centre represents a thinner region, not a hole.
Oxygen carriage and electrical-impulse conduction are different roles. Give the red-cell function precisely and connect haemoglobin to oxygen, rather than calling the cell a general messenger.
Pause and explain
Why does a mature mammalian red cell not disprove the typical animal-cell comparison?
Worked example
A mature mammalian cell contains haemoglobin and lacks a nucleus. Name the cell and function.
Show the worked solution
- Haemoglobin supports oxygen carriage.
- This is the specialised mature red blood cell.
Answer Mature mammalian red blood cell; oxygen transport.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
State the function of red blood cells and the protein involved.
Give me a hint
Link protein to transported gas.
Compare my reasoning
- Red cells transport oxygen.
- Haemoglobin supports carriage.
Oxygen transport using haemoglobin.
Look for these in your work
- Both gas and protein.
- Do not name chlorophyll.
Explain why the pale centre of a biconcave red-cell sketch is not a hole.
Give me a hint
Biconcave describes thickness.
Compare my reasoning
- The central region is thinner.
- The membrane encloses continuous cell contents.
It is a thinner region of the disc, not an open hole.
Look for these in your work
- Correct shape interpretation.
- Retain cell continuity.
A student classifies any nucleus-free cell as a bacterium. Use a red-cell example to correct the rule.
Give me a hint
State the specialised exception precisely.
Compare my reasoning
- Mature mammalian red cells lack nuclei.
- They are specialised animal cells.
- Use combined structure and context, not one missing feature.
Nucleus absence alone is insufficient; mature mammalian red cells are animal cells.
Look for these in your work
- Precise counterexample.
- Combined evidence.
Common mistakes
- The disc has a thinner centre, not a hole.
- Qualify the no-nucleus statement to mature mammalian cells.
What can you explain now?
Which protein supports oxygen transport in red blood cells?
Compare with the explanation
Haemoglobin.
It binds oxygen for carriage in the blood.
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Make it stick
Explain oxygen transport and the limit of the typical-cell model.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.