| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Biology |
| Lesson Topic: describe the transport of water from the soil to the xylem through the: apoplast pathway, including reference to lignin and cellulose, symplast pathway, including reference to the endodermis, Casparian strip and suberin |
Learning Objective/s:
- Describe the apoplast and symplast pathways for water movement from soil to xylem.
- Explain the roles of cellulose, lignin, the Casparian strip, and suberin in regulating water transport.
- Compare the speed and regulation of apoplastic versus symplastic transport.
- Identify how water crosses the endodermis via plasma membranes and aquaporins.
- Apply knowledge to interpret root cross‑section diagrams showing these pathways.
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Materials Needed:
- Projector or interactive whiteboard
- PowerPoint/slide deck with root diagram
- Handout containing a labelled root cross‑section
- Worksheet with a comparison table for the two pathways
- Prepared root microscope slides (optional)
- Whiteboard and markers
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Introduction:
Begin with a quick animation showing water rising through a plant, prompting students to consider how water enters the root. Recall prior learning on diffusion and cell‑wall structure, linking it to the upcoming discussion of apoplastic and symplastic routes. State that by the end of the lesson students will be able to describe each pathway and the key barriers that control water flow.
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Lesson Structure:
- Do‑now (5'): Students label a blank root cross‑section diagram with apoplast and symplast routes.
- Mini‑lecture (10'): Present the apoplast pathway, emphasizing cellulose, lignin, and the Casparian strip.
- Guided inquiry (10'): Using the slide, students fill a comparison table of apoplast vs. symplast characteristics.
- Hands‑on activity (15'): Groups examine microscope slides of root tissue, identify endodermal cells, Casparian strip, suberin, and discuss water entry via aquaporins.
- Check for understanding (5'): Exit ticket – write a brief explanation of how water moves from the cortex into the xylem.
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Conclusion:
Summarise that water initially travels through the cell‑wall network before being forced into the cytoplasmic route by the Casparian strip and suberin. Ask a few students to share their exit‑ticket responses to reinforce the sequence of events. Assign a homework task to create a labelled diagram of the two pathways and annotate the structural components.
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