4.3 Gas Exchange (plants)

Question 1

gas exchange at a stomata

Answer 1

oxygen diffuses out of the stomata

carbon dioxide diffuses in through the stomata

to reduce water loss by evaporation, stomata close at night when photosynthesis wont be occuring

Question 2

how are plant leaves adapted for gas exchange

Answer 2

Spongymesophyll layer provides large surface area
Waxy cuticle is impermeable to gas preventing excessive water loss
Lenticels(loosely arranged cells) allow gases to enter and leave

Question 3

Explain how the structure of this leaf ensures that the water potential at X remains high.

Answer 3

less transpiration because of the waxy cuticle which traps water vapour