A lizard loses part of its tail as a defence mechanism against a predator. Over several weeks, the tail grows back. Explain how mitosis allows the lizard's tail to grow back.

Cambridge International IGCSE Biology (0610) — 17.2 Mitosis · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

1. Cells in the remaining tail tissue undergo mitosis to produce new cells.
2. Mitosis results in two daughter cells that are genetically identical to the parent cell.
3. The diploid chromosome number is preserved in the daughter cells, maintaining genetic stability.
4. These new cells can differentiate into the specialised cells needed to rebuild the tail tissue and repair damage.

Examiner tips

  • Use the word ‘mitosis’ and explain the division process; mention identical daughter cells and diploid number; show how new cells specialise for tissue repair.
  • Structure answer in clear points matching the mark scheme; include key terms like ‘genetically identical’ and ‘diploid’.

Common mistakes

  • Confusing mitosis with meiosis or describing gamete formation; not stating that daughter cells are genetically identical; omitting the maintenance of diploid chromosome number; failing to link new cells to tissue repair.

Mark scheme (4 marks)

  1. Cells in the tail divide by mitosis to produce new cells
  2. Mitosis produces two daughter cells that are genetically identical to the parent cell
  3. The diploid chromosome number is maintained in the daughter cells
  4. The new cells can become specialised to replace the lost tail tissue / repair the damaged tissue

Key terms in this question

mitosis

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