# Describe how mutations can lead to genetic variation within a population of organisms.

> Edexcel GCSE Biology (1BI0) — 3.5 Variation and mutation · Describe · 4 marks

> A population of bacteria was exposed to ultraviolet (UV) radiation. After several generations, scientists observed that some bacteria in the population had developed new characteristics not seen in the original population.

## Mark scheme (4 marks)

1. A mutation is a random change in the base sequence of DNA
2. Mutations may produce new alleles (versions of a gene)
3. Different alleles can lead to differences in the proteins produced / coded for
4. This results in differences in phenotype / observable characteristics between organisms in the population

## Key terms

- [mutation](https://www.gradenine.co.uk/glossary/mutation)
- [genetic variation](https://www.gradenine.co.uk/glossary/genetic-variation)

## Related

- [Revision notes for Edexcel GCSE Biology (1BI0)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/describe-how-mutations-can-lead-to-0ca7b327) · Published by Druglandscape Ltd.