Mass transport in plants

Question 1

Role of xylem

Answer 1

Transport if water and mineral ions from the roots up to the leaves

Question 2

Role of phloem

Answer 2

Transport of sugars from leaves to respiring cells

Question 3

Roles of water in plants

Answer 3

• Cell turgidity
• Metabolite
• Hydrolysis reactions
• Transport of inorganic ions

Question 4

By what process are mineral ions taken into root hair cells?

Answer 4

Active transport

Question 5

Explain movement of minerals and water into xylem

Answer 5

Minerals actively transported into xylem, lowering water potential. Water follows by osmosis

Question 6

Features of xylem vessels

Answer 6

• Hollow (cells have no end wall)
• Lignified (lignin in cell walls - structural polymer)
• Long continuous tube
• Very rigid (due to lignin forming in helices)

Question 7

What is the transpiration stream?

Answer 7

Bulk transport of water up the stem of a plant through xylem vessels (passive)

Question 8

What is transpiration?

Answer 8

Evaporation of water from plants’ leaves

Question 9

What 3 forces aid movement of water through transpiration stream?

Answer 9

1. Pulling force - due to evaporation of water from leaves
2. Root pressure - water taken into the roots by osmosis - pushing force
3. Capillary action in xylem

Question 10

What is capillary action?

Answer 10

Combination of adhesion and cohesion, aiding upward movement of water. Continuous unbroken column of water molecules

Question 11

Lesson 69 slide 11