IGCSE Biology glossary
Nicotine
Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.
Definition
An addictive chemical in tobacco smoke that stimulates the nervous system and causes the release of adrenaline, increasing heart rate and blood pressure. Nicotine is the substance responsible for tobacco addiction and makes it difficult to stop smoking.
What to include in an exam answer
Nicotine is the addictive component. It raises heart rate and blood pressure. Link to increased risk of cardiovascular disease, not to lung cancer (that is tar's role).
Example in context
Explain why it is difficult for smokers to stop smoking (1 mark): Nicotine in tobacco smoke is addictive, creating a physical dependence that causes withdrawal symptoms when smoking stops.
Related syllabus topic
Gas exchange in humans