Scientists studied workers aged 45 to 54 to investigate whether exposure to ionising radiation interacts with an inherited allele, R, that reduces DNA repair.
The workers had the same age distribution in each group.
| Group | Allele R present | Mean occupational exposure to ionising radiation before the study (years) | Number who developed cancer per 1000 workers during the next 10 years |
|---|---|---|---|
| A | no | 1 | 8 |
| B | yes | 1 | 15 |
| C | no | 15 | 26 |
| D | yes | 15 | 61 |
Explain how the data and biological mechanisms support the conclusion that ionising radiation exposure and allele R interact to increase cancer risk.
Your answer should also explain why this study does not prove that ionising radiation caused the cancers.
102 exam-style questions on Edexcel GCSE Biology 5.4 Non-communicable diseases, covering 5.4.1 Interaction of factors in non-communicable disease, 5.4.2 Lifestyle factors and non-communicable disease, and 5.4.3 Treatments for cardiovascular disease. Each one has a worked solution and a mark scheme showing where the marks go.