Edexcel IGCSE Biology 2.44B net gas exchange in leaves
Practise respiration practicals using indicator colour, CO2 release, light intensity and the balance between respiration and photosynthesis.
- Syllabus
- First assessment 2019
- Course
- Biology 4BI1
Exam points
- explain unchanged indicator colour when CO2 released equals CO2 absorbed
- predict net CO2 or O2 exchange in bright light, low light or darkness
2.44B Light intensity and net gas exchange question 1
The diagram shows a single-celled organism called Chlorella that lives in fresh water. Chlorella has a chloroplast and can photosynthesise.
The graph shows the effect of light intensity on gas exchange by Chlorella.
oxygen released by Chlorella
oxygen taken in by Chlorella
Explain why Chlorella takes in oxygen at light intensities below 10 arbitrary units.
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