IGCSE Biology glossary
Denaturation
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
A permanent change in the shape of an enzyme's active site, caused by high temperature or unsuitable pH, so the substrate no longer fits and the enzyme stops working.
What to include in an exam answer
Never write that the enzyme is 'killed'. Enzymes are not alive, and that word loses the mark every time. The mark scheme wants: active site changes shape, substrate no longer fits/binds, reaction stops.
Example in context
Explaining why an enzyme stops working at 60 °C: 'The high temperature changes the shape of the enzyme's active site permanently, so the substrate no longer fits and the reaction stops.'
Related syllabus topic
Enzymes