Explain why organisms produced by asexual reproduction are genetically identical to their parent, whilst organisms produced by sexual reproduction are not.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Asexual reproduction uses only one parent and no fusion of gametes, so the offspring receive a copy of the parent’s DNA. The process is mitosis, which produces genetically identical daughter cells.
Sexual reproduction requires the fusion of male and female gametes (fertilisation), so the offspring receive half of their DNA from each parent. Gametes are produced by meiosis, which generates non‑identical cells and introduces genetic variation.
Sexual reproduction requires the fusion of male and female gametes (fertilisation), so the offspring receive half of their DNA from each parent. Gametes are produced by meiosis, which generates non‑identical cells and introduces genetic variation.
Examiner tips
- Use the exact terms: asexual, mitosis, identical; sexual, fertilisation, meiosis, variation.
- Show the logical link: one parent → mitosis → identical; two parents → meiosis → variation.
- Keep each point brief to fit the 4‑mark structure.
Common mistakes
- Confusing mitosis with meiosis for asexual reproduction.
- Saying ‘sexual reproduction is random’ instead of explaining gamete fusion and meiosis.
- Omitting that asexual reproduction involves only one parent.
Mark scheme (4 marks)
- Asexual reproduction involves only one parent / no fusion of gametes
- Asexual reproduction involves mitosis, which produces genetically identical cells
- Sexual reproduction involves the fusion of male and female gametes (fertilisation), combining genetic material from two parents
- Gametes are produced by meiosis, which creates non-identical cells / introduces genetic variation
Key terms in this question
asexual reproduction · sexual reproduction
Related
- Revision notes: Reproduction →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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