| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Biology |
| Lesson Topic: investigate the progress of enzyme-catalysed reactions by measuring rates of formation of products using catalase and rates of disappearance of substrate using amylase |
Learning Objective/s:
- Describe the role of enzymes as biological catalysts and define key terms such as active site and enzyme‑substrate complex.
- Explain how reaction rates can be measured by product formation (catalase) and substrate disappearance (amylase).
- Calculate initial reaction rates from volume‑time and absorbance‑time data and use them to estimate Vmax and Km.
- Analyse the influence of temperature and pH on enzyme activity and identify optimum conditions.
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Materials Needed:
- 10 mL test tubes, stopwatch, and thermostatic water bath
- 3 % H₂O₂ solution and potato/liver homogenate (catalase source)
- Gas syringe or inverted graduated cylinder for O₂ collection
- Iodine solution, 1 % starch solution, and saliva or pancreatic extract (amylase source)
- pH buffer solutions for amylase trials
- Spectrophotometer (optional) and worksheets/calculator
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Introduction:
Begin with a short video showing bubbles forming when hydrogen peroxide contacts potato tissue to spark curiosity. Review prior knowledge of enzymes, active sites and factors influencing activity. Outline success criteria: students will accurately record time‑resolved data, calculate initial rates and interpret how temperature or pH alters enzyme performance.
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Lesson Structure:
- Do‑now (5'): quick quiz on enzyme terminology and factors affecting activity.
- Mini‑lecture (10'): rate equations, Michaelis–Menten concepts, and how to derive rates from data.
- Demonstration – Catalase experiment (15'): students set up test tubes, add enzyme, collect O₂ at 10‑second intervals.
- Group analysis (10'): plot O₂ volume vs time, determine initial slope (v₊P) and discuss temperature effects.
- Demonstration – Amylase iodine test (15'): students add amylase to starch, sample at 30‑second intervals, add iodine, record colour change or absorbance.
- Group analysis (10'): plot absorbance vs time, calculate initial slope (v₋S) and explore pH influence.
- Comparison discussion (10'): contrast product‑formation vs substrate‑disappearance methods, identify optimum conditions and denaturation.
- Exit ticket (5'): each student writes one factor that shifts an enzyme’s optimum temperature and why.
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Conclusion:
Summarise how the two experimental approaches provided complementary ways to quantify enzyme kinetics. Students complete an exit ticket describing one factor that shifts the optimum temperature for an enzyme. For homework, ask learners to design a brief experiment investigating a different enzyme using either product formation or substrate disappearance, specifying the variable they would test.
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