Need help with gaurd cells in botany?

Question

fill in the blanks:

stomata is surrounded by gaurd cells which fill with water to ___ or lose water to ___

Answer 1

um gain ( opposite of lose)

and the other maybe the air??

Answer 2

When water moves into the guard cells, the pressure increase.  This increasing pressure presses against the cell wall which is made in such a way that it will bulge out, creating a hole we call a stomate.  When the water moves out of the cells, there is less pressure, the cells unbulge and the the hole goes away.

Here is an animation of the process:

http://academic.kellogg.cc.mi.us/herbran...