October 26, 2022
Photosynthesis
Light is absorbed by chloroplast that contain chlorophyll.
Carbon dioxide enters leaf through stomata.
Carbon dioxide + water à glucose + oxygen
6 CO2 + 6 H2O à C6H12O6 + 6 O2
Limiting factors mentioned in IGCSE biology:
- Carbon dioxide
- Light intensity
Role of Diffusion in gas exchange in plants
- Oxygen and carbon dioxide diffuse into the leaf through stomata
- During day, excess oxygen diffuses out of the leaf into atmosphere
Leaf Structure
Adaptation à large surface area, thin, flat
Please remember of functions of leaf structure stated in IGCSE biology,
- Waxy cuticle à To prevent transpiration
- Upper epidermis à transparent to allow sunlight to enter leaf.
- Palisade mesophyll à contains a lot of chloroplasts which absorb light for photosynthesis
- Spongy mesophyll à air spaces to allow diffusion of gases
- Vein à contains xylem and phloem
- Guard cells à control opening and closure of stomata
- Stomata à allows carbon dioxide in and oxygen out of leaf
End of this topic!
Drafted by Gina (Biology)