Explain why cell replication by mitosis is essential for the growth and repair of a multicellular organism. In your answer, refer to the genetic material of the cells produced.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (5 marks)
Mitosis produces new cells, increasing cell number and body size, which is essential for growth.
Mitosis replaces damaged or worn‑out cells, allowing repair and maintenance of tissues.
The daughter cells are genetically identical to the parent cell, ensuring the same DNA sequence.
Each daughter cell contains the same number of chromosomes as the parent, maintaining ploidy.
Thus the new cells have the correct genetic instructions to perform the same functions as the original cells.
Mitosis replaces damaged or worn‑out cells, allowing repair and maintenance of tissues.
The daughter cells are genetically identical to the parent cell, ensuring the same DNA sequence.
Each daughter cell contains the same number of chromosomes as the parent, maintaining ploidy.
Thus the new cells have the correct genetic instructions to perform the same functions as the original cells.
Examiner tips
- Use the exact wording from the mark scheme, e.g. "genetically identical" and "same number of chromosomes".
- Show the logical link between mitosis, cell number, and growth/repair.
- Include all five points in separate sentences or bullet points.
- Keep the answer concise and avoid unnecessary explanation.
Common mistakes
- Confusing mitosis with meiosis or not mentioning chromosome number.
- Using vague terms like "new cells" without specifying genetic identity.
- Leaving out the point about repair/maintenance.
Mark scheme (5 marks)
- Mitosis produces new cells for growth (increase in cell number / body size)
- Mitosis produces new cells to replace damaged or worn-out cells (repair / replacement)
- The daughter cells produced are genetically identical to the parent cell
- Each daughter cell contains the same number of chromosomes as the parent cell
- This ensures the new cells can carry out the same functions / have the correct genetic instructions to function properly in the organism
Key terms in this question
Related
- All AQA A-Level Biology (7402) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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