| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Biology |
| Lesson Topic: describe the role of chloroplast pigments (chlorophyll a, chlorophyll b, carotene and xanthophyll) in light absorption in thylakoids |
Learning Objective/s:
- Describe the specific absorption peaks and thylakoid locations of chlorophyll a, chlorophyll b, carotene, and xanthophyll.
- Explain how energy is transferred from antenna pigments to reaction‑centre chlorophyll a.
- Analyze the protective roles of carotene and xanthophyll under high‑light conditions.
- Compare the contributions of each pigment to overall light‑harvesting efficiency.
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Materials Needed:
- Projector or interactive whiteboard
- PowerPoint slides with pigment spectra diagrams
- Handout summarising pigment properties
- Model of a thylakoid membrane (paper or 3‑D)
- Colored markers or crayons for student diagrams
- Exit‑ticket cards
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Introduction:
Begin with a striking image of a green leaf under sunlight and ask students what gives it its colour. Recall previous learning about photosynthesis and the role of chlorophyll. Explain that today they will uncover how four different pigments work together to capture light and protect the plant, and that they will be able to identify each pigment’s function by the end of the lesson.
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Lesson Structure:
- Do‑Now (5'): Students list known pigments and predict their functions; quick whole‑class share.
- Mini‑lecture (10'): Present pigment locations, absorption peaks, and primary roles using slides and a thylakoid diagram.
- Guided inquiry (12'): In small groups, students analyse pigment data and construct an energy‑flow diagram, explaining each transfer step.
- Interactive simulation (8'): Use an online photosynthesis model to visualise resonance energy transfer and the xanthophyll cycle.
- Concept check (5'): Whole‑class Kahoot quiz focusing on pigment functions and protective mechanisms.
- Exit ticket (5'): Students write one sentence summarising how the four pigments cooperate in light absorption.
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Conclusion:
Summarise how chlorophyll a drives charge separation while chlorophyll b, carotene, and xanthophyll broaden absorption and provide protection. Prompt students to complete an exit ticket stating the cooperative role of the pigments. Assign homework to create a labelled sketch of a thylakoid cross‑section highlighting each pigment.
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