Edexcel IGCSE Biology · Spec 2.10-2.13
Enzymes
How enzymes work using the lock-and-key model, enzyme specificity, and the effect of temperature and pH on activity.
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Enzymes
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Spec 2.10-2.13
What you need to know
- Explain how enzymes work as biological catalysts
- Describe the effect of temperature on enzymes
- Describe the effect of pH on enzymes
Active recall
Quick check
Answer each question before opening the answer.
What is an enzyme and how does the 'lock and key' model work?
A protein that acts as a biological catalyst. The substrate fits the specific active site (like a key in a lock), forming an enzyme-substrate complex.
What happens to an enzyme at high temperature?
It denatures — the active site changes shape so the substrate no longer fits and the reaction stops.
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