2.44B Gas Exchange: Night vs Day (Edexcel IGCSE Biology)
Revision Note
Author
LáraExpertise
Biology Lead
Gas Exchange: Day & Night
- Plants can only photosynthesise when they have access to light, however, cells respire all the time
- This means that gas exchange in plants varies throughout a 24 hour period
- During the daytime plants both respire and photosynthesise
- The rate of photosynthesis tends to be higher than the rate of respiration (unless there is a low light intensity)
- Therefore there is net diffusion of carbon dioxide into the plant and net diffusion of oxygen out of the plant during the day
- During the nighttime, plants only respire
- This means that there is a net movement of oxygen into the plant and net diffusion of carbon dioxide out of the plant during the night time
- At low light intensities, the rate of photosynthesis is equal to the rate of respiration
- This means that there is no net movement of oxygen or carbon dioxide in either direction
Plants photosynthesise and respire during the day but only respire at night time
You've read 0 of your 0 free revision notes
Get unlimited access
to absolutely everything:
- Downloadable PDFs
- Unlimited Revision Notes
- Topic Questions
- Past Papers
- Model Answers
- Videos (Maths and Science)
Did this page help you?