Respiration Experiments

• What is produced during respiration that can be detected using hydrogen-carbonate solution?

  Carbon dioxide (CO₂)
• What color does hydrogen-carbonate solution turn when there is plenty of CO₂ present?

  Yellow
• How can you set up an experiment to demonstrate CO₂ production by germinating beans?

  1. Soak dried beans in water for 1-2 days to germinate.
  2. Boil a second bunch of dried beans to kill them (control).
  3. Place hydrogen-carbonate indicator in two test tubes.
  4. Use gauze to hold the beans above the indicator.
  5. Seal with a rubber bung and leave for a set time.
  6. Observe the color change of the indicator.
• What is the purpose of boiling a second bunch of dried beans in the experiment?

  To kill the beans and ensure they cannot respire
• What should be used as a control when experimenting with small organisms like woodlice or maggots?

  Glass beads
• How can the experiment be extended to investigate the rate of respiration?

  By timing how long it takes for the hydrogen-carbonate indicator to turn yellow for different organisms
• What is the purpose of the vacuum flask in the experiment measuring energy transferred by heat during respiration?

  • To insulate the beans
  • To allow aerobic respiration by leaving air in the flask
  • To measure temperature changes due to heat transfer
• What should be recorded daily in the experiment using vacuum flasks with beans?

  The temperature of each flask
• What happens to the temperature of the test flask with germinating beans compared to the control flask?

  The temperature will increase in the test flask
• Why are controls important in experiments?

  To ensure that the independent variable is affecting the results and nothing else
• What ethical consideration is mentioned regarding the use of woodlice in experiments?

  You cannot go around killing woodlice
• What humorous remark is made about beans in the lab?

  My beans keep disappearing from the lab — must be runner beans…
• What is the main purpose of the respiration experiments described?

  To demonstrate CO₂ production and energy transfer during respiration