Edexcel IGCSE Biology · Spec 2.45B
Light and Gas Exchange
Required practical: using hydrogencarbonate indicator to investigate the effect of light on gas exchange in plants.
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Light and Gas Exchange
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Spec 2.45B
What you need to know
- Use hydrogencarbonate indicator to detect carbon dioxide
- Investigate the effect of light on a plant
- Explain the results
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Quick check
Answer each question before opening the answer.
What is happening at the compensation point?
The rate of photosynthesis exactly equals the rate of respiration, so there is no net gas exchange.
How could you investigate the effect of light on a leaf's gas exchange?
Use hydrogencarbonate indicator with a leaf kept in the light and one in the dark, and compare the colour changes.
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