Lesson Plan

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Lesson Plan
Grade: Date: 25/02/2026
Subject: Biology
Lesson Topic: describe the sequence of events that results in an action potential in a sensory neurone, using a chemoreceptor cell in a human taste bud as an example
Learning Objective/s:
  • Describe the step‑by‑step ionic events that lead from tastant binding to an action potential in the afferent sensory neurone.
  • Explain the role of the taste (chemoreceptor) cell versus the sensory neurone in signal transduction.
  • Interpret how threshold potentials for Ca²⁺ and Na⁺ channels determine the onset of neurotransmitter release and action‑potential generation.
  • Apply the sequence to a new example (e.g., a different tastant) by predicting the ion movements.
Materials Needed:
  • Projector or interactive whiteboard
  • PowerPoint/Google Slides with diagram of a taste bud
  • Handout summarising the ion‑movement table
  • Clicker or online quiz tool for quick checks
  • Model of a neuron (optional) for a brief demonstration
 Introduction:
Begin with a quick demonstration of a salty snack to spark curiosity about how we taste. Ask students what they already know about how chemicals become electrical signals. Outline that by the end of the lesson they will be able to trace every ion movement from the taste cell to the brainstem and state the success criteria: a clear, ordered description of the action‑potential cascade.
Lesson Structure:
  1. Do‑Now (5'): Students list the main parts of a taste bud on sticky notes; teacher collects for a quick mind‑map.
  2. Mini‑lecture with diagram (10'): Explain the anatomy of the chemoreceptor cell, synaptic cleft, and sensory neurone; highlight ion channels.
  3. Guided walkthrough (15'): Step‑by‑step narration of the nine events, using the slide’s ion‑movement table; pause for student questions after each major transition.
  4. Interactive simulation (10'): Students use an online model to manipulate tastant concentration and observe changes in membrane potential.
  5. Collaborative task (10'): In pairs, students create a flow‑chart that predicts what would happen with a different tastant (e.g., sweet) and present one key difference.
  6. Formative check (5'): Clicker quiz with 3 rapid‑fire questions on threshold values and neurotransmitter identity.
Conclusion:
Recap the full cascade, emphasizing the distinction between graded depolarisation in the taste cell and the all‑or‑none action potential in the neurone. Have students write one “exit ticket” sentence summarising the critical threshold step. Assign a brief homework: sketch the sequence for a bitter tastant and label the ions involved.