A lesson on aerobic and anaerobic respiration built around a marathon hook and a yeast practical. It explains respiration with and without oxygen, what happens in muscles during exercise, and the equation for anaerobic respiration in yeast, then sets up an experiment measuring carbon dioxide from different drinks.
What this presentation covers
- why living things break down sugar
- aerobic respiration
- what happens in muscles during exercise
- anaerobic respiration and lactic acid
- fermentation in yeast
- a practical using a carbon dioxide sensor to compare drinks
Level: KS3 / GCSE
Slides: 16
Format: PowerPoint (.pptx)
Teaching notes
How to use it. Suits KS3 and GCSE Biology. The marathon hook works well as a starter: ask why runners slow down and get cramp near the end. The yeast practical can be done with balloons over bottles if you do not have a carbon dioxide sensor, comparing how much each balloon inflates with different sugary drinks.
Key words
- Aerobic respiration: releasing energy from glucose using oxygen
- Anaerobic respiration: releasing energy from glucose without oxygen
- Lactic acid: the product of anaerobic respiration in muscles
- Oxygen debt: the extra oxygen needed after exercise to break down lactic acid
- Fermentation: anaerobic respiration in yeast, which makes ethanol and carbon dioxide
Common misconception: “Respiration is the same as breathing.” Breathing moves air in and out of the lungs. Respiration is a chemical reaction in every living cell that releases energy from glucose.
Quick check questions
- Write the word equation for aerobic respiration.
- Why do muscles respire anaerobically during hard exercise?
- What does yeast produce during anaerobic respiration?
Show answers
- Glucose + oxygen → carbon dioxide + water.
- They cannot get enough oxygen fast enough for aerobic respiration.
- Ethanol and carbon dioxide.
Related lessons: Photosynthesis | The Lungs | Krebs Cycle
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