Lesson Plan

• Describe the structure of stomata and the function of guard cells in gas exchange.
• Explain how stomata regulate CO₂ intake and O₂ release during photosynthesis.
• Analyze the environmental and hormonal factors that cause stomata to open or close.
• Evaluate the trade‑off between carbon fixation and water loss mediated by stomata.

• Projector and slide deck
• Prepared handout with stomata diagram
• Fresh leaf specimens (e.g., spinach)
• Microscopes or hand lenses
• Worksheet for labeling and questions
• Whiteboard and markers
• Online simulation or quiz platform (e.g., Kahoot)

Begin with a quick question: “Do plants breathe? How?” to hook interest. Review students’ prior knowledge of photosynthesis and the need for carbon dioxide. State that by the end of the lesson they will be able to identify stomatal structures, describe their role in gas exchange, and list factors that control their opening.

1. Do‑now (5'): Write three gases involved in plant gas exchange and their direction of movement.
2. Mini‑lecture with slides (10'): Explain stomatal anatomy, guard‑cell mechanism, and the basic gas‑exchange process.
3. Microscopy activity (15'): Students examine leaf epidermis, label guard cells, pore, and epidermal cells on the handout.
4. Guided discussion (10'): Use a chart to explore factors influencing stomatal opening (light, CO₂, water, temperature, hormones).
5. Interactive simulation/quiz (10'): Students test understanding of stomatal responses using an online tool.
6. Summary & exit ticket (5'): Each pupil writes one sentence summarising how stomata balance photosynthesis and water loss.

Recap the key points: stomata as gateways for CO₂ uptake and O₂ release, the guard‑cell mechanism, and the environmental cues that modulate opening. Collect exit‑ticket sentences as a quick assessment. For homework, ask students to research how drought conditions affect stomatal behaviour and write a short paragraph.