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Edexcel IGCSE Biology · Spec 2.39

Respiration Practical

Required practical: showing that respiring organisms release carbon dioxide and heat, using a control.

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Respiration Practical

Spec 2.39

What you need to know

  • Show that respiring organisms release carbon dioxide
  • Show that respiration releases heat
  • Explain why we use a control

Active recall

Quick check

Answer each question before opening the answer.

How can you show that living organisms produce carbon dioxide?

Use hydrogencarbonate indicator (turns yellow) or limewater (turns milky/cloudy) with the respiring organisms.

Why do you need a control tube with no organisms?

To show the result is caused by the organisms and not by other factors.

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