Lesson Plan

• Describe the role of the active site in enzyme specificity.
• Explain how the enzyme‑substrate complex forms and leads to product formation.
• Illustrate the step‑by‑step sequence of an enzyme‑catalysed reaction.
• Compare substrate and product characteristics in the context of enzyme action.
• Identify common misconceptions about enzymes and correct them.

• Projector and screen
• Whiteboard and coloured markers
• Printed diagram handouts of enzyme action
• Worksheet with enzyme‑reaction scenarios
• Interactive simulation (e.g., PhET)
• Model kits of enzyme‑substrate complexes

Begin with a “lock‑and‑key” analogy to hook students and show how enzymes speed up reactions. Ask learners what they already know about catalysts and chemical reactions in cells. Explain that by the end of the lesson they will be able to label the active site, describe the enzyme‑substrate complex, and differentiate substrate from product.

1. Do‑now (5'): Quick quiz on general catalysts and their effects.
2. Mini‑lecture with slides (10'): Define enzymes, active site, substrate, ES complex, and product.
3. Guided diagram labeling (10'): Students label printed diagrams of the enzyme action sequence.
4. Interactive simulation (10'): Explore ES formation and induced‑fit using a digital model.
5. Group activity (15'): Create a flow‑chart of the reaction steps using cards and present to the class.
6. Check for understanding (5'): Exit‑ticket question – “What happens to the enzyme after the product is released?”

Summarise the key stages of enzyme action and reinforce the specificity of the active site. Collect the exit tickets to gauge understanding and assign a short homework: complete a worksheet comparing substrate and product features. Remind students that enzymes are unchanged after the reaction and can be reused.