| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Biology |
| Lesson Topic: state that the respiratory quotient (RQ) is the ratio of the number of molecules of carbon dioxide produced to the number of molecules of oxygen taken in, as a result of respiration |
Learning Objective/s:
- Describe the definition of the respiratory quotient (RQ) and write its formula.
- Explain how RQ reveals which metabolic substrate (carbohydrate, fat, or protein) is being oxidised.
- Calculate RQ from given volumes of O2 consumed and CO2 produced.
- Interpret typical RQ values (≈1.0, 0.7, 0.8) for different substrates.
- Evaluate the importance of RQ in estimating metabolic rate and nutritional status.
|
Materials Needed:
- Projector or interactive whiteboard
- PowerPoint slides with RQ diagram and substrate table
- Handout containing the RQ formula and example data
- Model or schematic of a closed metabolic chamber
- Calculators
- Worksheet for RQ calculations
|
Introduction:
Begin with a quick question: “What gases are exchanged during aerobic respiration?” Connect this to students’ prior knowledge of respiration and set the success criteria – they will be able to define RQ, calculate it, and interpret its meaning.
|
Lesson Structure:
- Do‑now (5 minutes): Short quiz on oxygen uptake and carbon dioxide release.
- Mini‑lecture (10 minutes): Define RQ, present the formula RQ = VCO₂/VO₂, and show typical substrate values.
- Demonstration (10 minutes): Display the metabolic chamber diagram and explain how gas volumes are measured.
- Guided practice (15 minutes): In pairs, students calculate RQ from provided O₂ and CO₂ volume data and identify the dominant substrate.
- Concept check (5 minutes): Exit ticket – write the substrate indicated by an RQ of 0.7 and one implication of an RQ > 1.0.
|
Conclusion:
Recap the definition of RQ and its role as a metabolic indicator. Collect exit tickets to gauge understanding and assign a brief homework: calculate RQ from a new set of gas measurements and explain the result.
|