Explain the role of mitosis in repair of damaged tissues
Mitosis can supply cells for damaged-tissue repair. Invented counts of thirty-five survivors plus twenty new cells give fifty-five, five below a target of sixty.
Section 17.2 · Mitosis
Exam scope and assessment notes
Extended only (Supplement) · 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 chromosomes, genes, chromosome sets, selective gene expression and the distinction between a nucleus and a whole cell.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What is the relevant role of mitosis in tissue repair?
What you will learn
- Connect replacement production with repair
- Separate counts from restored function
Original teaching model. Counts and records are stipulated; drawings are schematic.
| Feature | Meaning |
|---|---|
| Role | Supply suitable cells for damaged-tissue repair |
| Invented record | 35 surviving + 20 new = 55 |
| Invented target | 60 cells; deficit 5 |
| Limit | Cell count alone does not establish restored function |
Connect replacement production with repair
Mitosis contributes to repair of damaged tissues by producing cells that can replace cells lost or damaged in the tissue. Dividing surviving cells or appropriate stem-cell populations supply daughter cells with preserved genetic information. The role is to generate cells for repair; their later growth, specialisation and organisation also matter for a functioning tissue.
This explanation does not mean every mature cell can divide or every damaged structure can be restored completely. Different tissues have different capacities, and not all specialised cells behave as actively dividing precursors. The syllabus asks for the role of mitosis in repair, not a promise of a particular medical outcome or instructions for treating an injury.
Separate counts from restored function
A fictional tissue record specifies a target of sixty functioning cells, thirty-five surviving cells and twenty newly added replacement cells. On those supplied counts alone, the represented population reaches fifty-five, leaving a deficit of five relative to the target. Those values are invented to practise a complete count; they are not clinical thresholds or a model of a real wound.
Even a restored count of sixty would not prove restored tissue function without further evidence. Cells must be appropriate for the tissue and arranged so that they can work together. Explain the causal contribution at the right level: mitotic production can help replenish cells, while a simple count cannot demonstrate every functional step of repair or prove which process created an observed increase.
Pause and explain
A target is sixty; thirty-five survive and twenty new cells are added. What is the numerical deficit?
Worked example
Thirty-five survivors plus twenty new cells are recorded against a target of sixty. What remains?
Show the worked solution
- Add the supplied populations.
- Compare with the target.
Answer Fifty-five cells are recorded, leaving five below the target; function is not established by the count alone.
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.
Explain why accurate mitosis can contribute to repair.
Give me a hint
Connect cell production and lost tissue cells.
Compare my reasoning
- Describe production of genetically matching daughters.
- Explain that suitable products can replace lost cells.
Accurate mitosis produces genetically matching daughter cells that, with suitable growth and organisation, can help replace damaged or lost tissue cells.
Look for these in your work
- Explain production
- Avoid guaranteeing all repair
Calculate the recorded total and deficit for thirty-five survivors plus twenty new cells against a target of sixty.
Give me a hint
Add first, then compare.
Compare my reasoning
- Calculate thirty-five plus twenty.
- Subtract the total from sixty.
The recorded total is fifty-five cells and the deficit is five cells.
Look for these in your work
- Show the addition
- Label the deficit
A fictional tissue returns to its earlier cell count. Explain why that does not by itself prove complete functional repair.
Give me a hint
Ask about cell type and organisation.
Compare my reasoning
- Identify the limited count evidence.
- State the missing functional evidence.
The count alone does not show that the cells are the appropriate types, correctly organised or performing the required functions; those aspects need further evidence.
Look for these in your work
- Acknowledge the count
- State additional evidence needs
Common mistakes
- Mitosis contributes to repair without guaranteeing complete recovery.
- A restored cell count is not proof of restored tissue function.
What can you explain now?
A target is sixty; thirty-five survive and twenty new cells are added. What is the numerical deficit?
Compare with the explanation
Five cells
Sixty minus fifty-five is five.
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Make it stick
Without your notes, connect replacement production with repair and separate counts from restored function. Distinguish nuclear division, chromosome copies and completed daughter cells before opening the solutions.
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.