IGCSE Biology: Drugs – Exam Tips & Revision Guide
This guide covers IGCSE Biology topic 15: drugs. You will revise medicinal drugs (antibiotics, painkillers), antibiotic resistance, and misuse of drugs (alcohol, smoking, illegal drugs) and their effects on health and society.
Key concepts to revise
- Antibiotics – Kill bacteria (not viruses). Overuse leads to antibiotic-resistant bacteria; finish the course.
- Painkillers – Relieve symptoms; do not kill pathogens (e.g. viruses).
- Alcohol – Depressant; affects brain (judgement, coordination); long-term: liver damage.
- Smoking – Nicotine (addictive); tar (carcinogen, damages lungs); carbon monoxide (reduces oxygen carrying capacity of blood).
Exam tips and command words
- State – What antibiotics kill (bacteria); why antibiotics do not work against viruses.
- Describe – The effect of alcohol on the nervous system; the effect of smoking on gas exchange (tar, cilia).
- Explain – Why antibiotic resistance develops (overuse; bacteria with mutation survive and reproduce); why finishing a course is important.
- Compare – Antibiotic vs painkiller (kill pathogen vs relieve symptom).
Common mistakes
- Saying antibiotics kill viruses (they do not; they kill bacteria).
- Confusing nicotine (addictive) with tar (carcinogen; damages lungs).
- Not stating that antibiotic resistance is a result of natural selection (resistant bacteria survive and pass on resistance).
Revision checklist
- State what antibiotics do and why they do not work against viruses.
- Explain how antibiotic resistance develops and how to reduce it (finish course; avoid overuse).
- Describe the effects of alcohol on the body (short-term and long-term).
- Describe the effects of smoking (nicotine, tar, carbon monoxide) on health.
Next steps
Book a free trial with an IGCSE Biology tutor to practise drugs and health questions, or explore Tutopiya’s learning portal for more revision resources.
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