2.43B: Describe the Role of Stomata in Gas Exchange

STOMATA: Mouth-shaped opening flanked and controlled by Guard cells to regulate gas exchange and prevent Water loss (via transpiration)

DURING THE DAY	DURING THE NIGHT
Stomata During the Day	Stomata During the Night
During the daytime, high light intensity will stimulate Guard cells to absorb Water via osmosis Guard cells become turgid, causing thick inner walls to split open Stomata opens Net exchange of gases occur (Carbon Dioxide will diffuse in, and Oxygen and Water vapour will diffuse out)	During the night, low light intensity will stimulate Guard cells to lose Water via osmosis Guard cells become flaccid, causing thick inner walls to split close Stomata closes Net exchange of gases does not occur