Transpiration

Question 1

What is transpiration?

Answer 1

the loss of water by evaporation from the leaves

the movement of water from the roots to the leaves (transpiration stream)

Question 2

Describe the journey of water through a plant.

Answer 2

• water enters the roots by osmosis/diffusion
• water drawn up the stem through the xylem from the roots
• water drawn into leaf cells from the xylem
• water vapour evaporates from leaves through the stomata

Question 3

How do guard cells work?

Answer 3

• guard cells are open when they take in water by osmosis and swell up
• when they lose water they become flaccid and the stoma closes

(the cell wall is thicker on the inside of the cell)

Question 4

How are water molecules pulled up the xylem vessels?

Answer 4

by weak forces of attraction between the molecules