Mass Transport in Plants

Question 1

Structure of Xylem Vessels

Answer 1

• Dead cells stacked end to end to form a continuous tube allows continuous flow of water
• No cytoplasm or organelles and no obstructions to flow
• No end walls (continuous flow of water)
• Lined with a waterproof coat made of polysaccharide lignin (spirals) (strengthens the vessels)

Question 2

What do xylem vessels transport?

Answer 2

Water and mineral ions from the roots upwards. They are unbroken continuous tubes from the roots to the leaves.

Question 3

Why do plants need water

Answer 3

For many metabolic reactions such as photosynthesis.

Question 4

How does water enter the plants?

Answer 4

Absorbed through the roots via osmosis.

Question 5

How are root hair cells adapted for absorption of water into the plant.

Answer 5

• They have finger-like extensions which line the epidermis of the roots which greatly increases the SA for absorption.

Question 6

What is a major force that drives water transport through the plant

Answer 6

• Evaporation of water at the leaves. This whole process is known as transpiration
• Energy supplied by sun hence passive.

Question 7

How does water move in the leaves

Answer 7

Water evaporates from the cell walls of mesophyll cells into air spaces in the leaf due to heat suppiled by the sun