Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Biology
Lesson Topic: calculate RQ values of different respiratory substrates from equations for respiration
Learning Objective/s:
  • Describe the concept of respiratory quotient (RQ) and its significance in metabolism.
  • Calculate RQ values for carbohydrates, fats, and proteins using balanced oxidation equations.
  • Interpret RQ results to identify the predominant substrate being oxidised.
  • Apply the calculation process to novel substrates in practice problems.
Materials Needed:
  • Projector or interactive whiteboard
  • Printed worksheets with oxidation equations and practice questions
  • Scientific calculators
  • Handout summarising RQ values for common substrates
  • Whiteboard and markers
 Introduction:
Begin with a quick poll: “What do you think happens to the amount of CO₂ produced when we burn fat versus sugar?” Recall that students have previously learned balanced aerobic oxidation equations. Today they will learn how to turn those equations into quantitative RQ values, and they will be able to demonstrate this by completing a short calculation by the end of the lesson.
Lesson Structure:
  1. Do‑Now (5'): Students list the balanced equation for glucose from memory; teacher checks understanding.
  2. Mini‑lecture (10'): Explain RQ definition, why it varies with substrate, and outline the four‑step calculation method.
  3. Guided practice (12'): Work through the palmitic‑acid example on the board, prompting students to identify CO₂ and O₂ moles.
  4. Collaborative activity (15'): In pairs, students use the worksheet to calculate RQ for alanine and a mixed‑diet scenario, recording answers on a shared Google Doc.
  5. Whole‑class check (8'): Review answers, address misconceptions, and highlight key patterns (carbohydrate ≈1, fat ≈0.7, protein >1).
  6. Exit ticket (5'): Each student writes one real‑world context where knowing RQ is useful and the corresponding RQ value.
Conclusion:
Summarise that RQ provides a quick snapshot of which fuel a cell is using, linking the stoichiometry of oxidation to physiological interpretation. Collect exit tickets to gauge understanding, and assign a homework task to calculate the RQ for fructose and a triglyceride, showing all steps.