Connect iron sources with haemoglobin
Explain an iron-containing protein’s oxygen-transport 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 large and small nutrient molecules, cell membranes and enzyme specificity.
- Use the stated diagram keys and evidence; models are not to scale.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Where is haemoglobin found?
What you will learn
- Explain an iron-containing protein’s oxygen-transport role.
- Distinguish the mineral component from the protein that uses it.
Compare calcium and iron
| Component | Examples of sources | Role |
|---|---|---|
| Calcium | Dairy; labelled fortified sources | Bones and teeth |
| Iron | Meat, pulses, fortified cereal | Needed for haemoglobin |
Identify dietary sources
Meat, beans, lentils and iron-fortified cereals can supply iron. Different foods contain different forms and amounts of iron. The food source is a mixture; an iron ion itself is not a protein molecule.
Iron is needed to make haemoglobin, the protein in red blood cells that carries oxygen. Relate the mineral to this specific function rather than saying iron creates oxygen.
Explain the transport link
Oxygen carried by haemoglobin supports aerobic respiration in tissues. A shortage of iron can impair haemoglobin production, but fatigue alone does not uniquely establish iron deficiency. This section teaches the source-function relationship.
Do not confuse iron with calcium’s main skeletal role or vitamin C’s connective-tissue role. The nutrients work in an organism with many linked processes, but their named syllabus functions are distinct.
Pause and explain
Which pair is correct?
Worked example
A question states that inadequate iron limits haemoglobin production. Explain the possible oxygen-transport consequence.
Show the worked solution
- Identify haemoglobin in red blood cells.
- State its oxygen-carriage role.
- Connect reduced production with reduced capacity.
Answer Inadequate iron can reduce haemoglobin production and therefore oxygen-carrying capacity.
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.
Name two iron sources and one function.
Give me a hint
Include a pulse.
Compare my reasoning
- Choose meat and lentils.
- State haemoglobin production.
Meat and lentils; iron is needed for haemoglobin that carries oxygen.
Look for these in your work
- Two suitable sources.
- Haemoglobin function.
A learner says iron and haemoglobin are the same substance. Explain the distinction.
Give me a hint
A mineral is part of a larger protein system.
Compare my reasoning
- Iron is a mineral component.
- Haemoglobin is an iron-containing protein.
Iron is required for haemoglobin, but an iron ion is not the whole protein.
Look for these in your work
- Distinct substances.
- Correct relationship.
A case gives tiredness but no nutrient or blood measurements. Can tiredness alone prove inadequate dietary iron?
Give me a hint
Many factors can cause the observation.
Compare my reasoning
- Iron inadequacy is one possible issue.
- The symptom is not unique.
- Additional evidence is needed.
No; the observation does not uniquely establish dietary iron deficiency.
Look for these in your work
- Limit the inference.
- Do not diagnose from one symptom.
Common mistakes
- Iron does not make oxygen atoms.
- One symptom does not uniquely identify iron deficiency.
What can you explain now?
Which pair is correct?
Compare with the explanation
Iron: needed for haemoglobin.
This links mineral and protein.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Trace iron to haemoglobin and oxygen carriage.
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.