Aerobic Respiration in Plants

This experiment demonstrates that aerobic respiration in living organisms such as germinating seeds releases heat energy and produces carbon dioxide. By comparing germinating and boiled (dead) peas or beans, students can observe temperature changes and detect CO₂ production, confirming respiration as an exothermic process that occurs only in living cells.

1. Gather materials: two vacuum flasks, thermometers, cotton wool, stopwatch, and two sets of peas or beans.
2. Soak both sets of peas or beans in water overnight to allow one batch to germinate.
3. Boil one set to kill the cells and enzymes (control group).
4. Place equal amounts of germinating peas in one flask and boiled peas in another, resting on moist cotton wool for air access.
5. Insert a thermometer into each flask through a cotton wool bung and record the initial temperatures.
6. Seal the flasks and keep them under the same conditions for several hours or days.
7. Record temperature changes daily.
8. Observe: the germinating seeds’ flask temperature rises due to heat released from aerobic respiration, while the control shows no change.

Respiration Experiments - GCSE Biology (9-1) - Mr Exham Biology:

Heat is released during Respiration - Science Projects:

📄 Experiment to investigate aerobic respiration in plants and fungi using germinating beans or peas to show heat energy release with the formation of carbon dioxide - WP Brown PhD: https://www.docbrown.info/ebiology/respiration-2.htm#:~:text=Method:,the%20heat%20comes%20from%20respiration.

• Repeat using yeast and glucose solution to compare respiration in fungi and plants.
• Use a digital temperature probe for more precise heat measurements.
• Test different numbers or masses of seeds to compare respiration rates.

• Handle boiling water carefully when preparing the control seeds.
• Do not seal flasks completely—living seeds require oxygen for aerobic respiration.
• Dispose of plant material hygienically after the experiment.
• Wash hands thoroughly after handling seeds or soil.

• What evidence shows that respiration releases heat? (The temperature in the germinating seed flask increases.)
• Why are boiled seeds used as a control? (Boiling kills the enzymes, preventing respiration.)
• What does the production of CO₂ confirm about the process occurring in the living seeds? (It shows aerobic respiration is taking place.)
• Why must air be allowed into the flask? (Oxygen is required for aerobic respiration.)
• How do these results demonstrate that respiration is an exothermic reaction? (Energy from glucose oxidation is released as heat and ATP.)
• What is the overall word equation for aerobic respiration? (Glucose + Oxygen → Carbon dioxide + Water + Energy.)