Radioactive materials can be hazardous to living organisms. Explain why ionising radiation from radioactive sources is dangerous to humans, and state one precaution that should be taken when handling radioactive sources.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Ionising radiation has enough energy to remove tightly bound electrons from atoms, producing ions. This ionisation can damage or kill cells and, importantly, damage DNA strands. Damaged DNA can lead to mutations that may result in cancer. Because the damage occurs at the cellular level, a person may not feel any immediate symptoms, yet the risk of long‑term disease remains.
A common precaution is to keep the source at a safe distance and minimise exposure time, for example by using tongs or a lead‑lined container when handling the material.
A common precaution is to keep the source at a safe distance and minimise exposure time, for example by using tongs or a lead‑lined container when handling the material.
Examiner tips
- Use the term ‘ionising radiation’ and explain its effect on DNA; link DNA damage to cancer. Mention lack of immediate sensation to show long‑term risk. State a specific precaution such as keeping a safe distance or using tongs. Keep answer concise and to the point.
Common mistakes
- Using non‑ionising radiation terms; claiming the radiation is harmless; giving a vague precaution like ‘wear gloves’ without specifying distance or shielding.
Mark scheme (4 marks)
- Ionising radiation can damage or kill cells / damage DNA / cause mutations
- Damaged DNA / mutations can lead to cancer
- Radiation can damage cells without the person being aware / there is no immediate sensation of exposure (linking to internal exposure or long-term risk)
- A correct precaution: e.g. use tongs / keep source at a distance / limit exposure time / store in lead-lined container / wear protective clothing / avoid pointing source at people
Key terms in this question
ionising radiation · precaution
Related
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