Q1. [3] deep thorough-understanding
A student argues: 'If DNA-copying were made less accurate, sexual reproduction would be unnecessary because enough variation would already be generated asexually.' Using your understanding of what happens when DNA copying becomes too inaccurate, explain why this argument is flawed.
Generated by claude-sonnet-4-6 · 2026-06-26 01:05 · grounding rag
Model Answer
The argument is flawed for the following reasons:
- Too many errors = cell death: If DNA copying became highly inaccurate, most of the resulting DNA copies would be unable to work with the cellular apparatus and the new cells would simply die. This reduces the population rather than generating useful variation.
- Sexual reproduction creates safe, novel combinations: Sexual reproduction combines DNA from two individuals who already carry variations accumulated over generations. Since these individuals are alive, their variations are proven to be non-lethal — making the new combinations both novel and viable.
- Conclusion: Extreme inaccuracy in DNA copying is destructive, not generative. Sexual reproduction generates variation safely and efficiently, making it irreplaceable.
Source: Chapter 7, Section 7.3.1 — Why the Sexual Mode of Reproduction?
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Explanation
Examiners expect three clear points for 3 marks:
- Point 1 (1 mark): Too much inaccuracy → cells die (directly from the passage).
- Point 2 (1 mark): Sexual reproduction combines pre-tested, accumulated variations from two living individuals — so new combinations are safe and novel.
- Point 3 (1 mark): Conclusion tying it together — inaccuracy destroys; sex reproduces variation safely.
Avoid writing a vague answer like "variation is important." Be specific: the passage says inaccurate copies "would not be able to work with the cellular apparatus, and would die" — quote or paraphrase this directly for full marks.