Transpiration

Question 1

What is transpiration

Answer 1

The loss of water vapour from the stomata by evaporation

Question 2

What does the xylem do

Answer 2

Moves water and minerals from the roots to the leaves against gravity

Question 3

What is the structure of the xylem

Answer 3

-dead cells stacked end to end
-no cell walls between cells so they form a continuous vessel
-lined with waterproof polysaccharides, lignin

Question 4

What are forces acting on the xylem

Answer 4

-cohesion
-adhesion (capillarity)
-root pressure

Question 5

What is cohesion tension

Answer 5

-water is dipolar
-weak hydrogen bonds form between water molecules enabling a continuous column up the xylem

Question 6

What is adhesion (capillarity)

Answer 6

Water adheres to xylem wall, the narrower the xylem the bigger the impact of capillarity

Question 7

What is Root pressure

Answer 7

-water moves into root hair cells via osmosis increasing the volume of liquid inside the root and therefore pressure increases which forces water uparwards
-positive pressure