Xylem and phloem

Question 1

What does xylem tissue do?

Answer 1

Transports water and minerals from roots

Question 2

How does water form the soil enter the roots?

Then where does the water travel?

What is the xylem?

Answer 2

By osmosis

Through the root to the xylem

Tissue that transports water through the plant and up to the leaves

Question 3

Name 2 ways water can travel through the roots

Answer 3

The symplast system and the apoplast system

Question 4

Describe the symplast system

Answer 4

Some water moves through the root via the cytoplasm of the root cells. the water has to cross the cell membrane, which regulates the passage of the water and dissolved minerals

Question 5

Describe the apoplast system

Answer 5

The water moves through the cells walls and the spaces between the cells

There are no membranes to regulate the passage

Question 6

How does water travel up the plant?

Answer 6

Through the xylem tissue

Question 7

Describe the cells that make up the tubes (vessels) of xylem tissue

What does this mean?

Answer 7

The cells are dead, waterproof and hollow

This means water can move through them easily

Question 8

How is water pulled up through the xylem tissue?

Answer 8

By a combination of factors - cohesion, tension and adhesion

Question 9

Describe how water is pulled up through the xylem tissue by cohesion, tension and adhesion (1,2,3)

Answer 9

1. Water evaporates from inside the leaf leaving a higher concentration of solutes
2. Water from the nearest xylem vessel enters by osmosis
3. Water molecules stick together because of weak hydrogen bonds between them - this is called cohesion

Question 10

Describe how water is pulled up through the xylem tissue by cohesion, tension and adhesion (4,5,6)

Answer 10

4. As water molecules leave the xylem vessel, they pull up further molecules, so the whole column of water is pulled up
5. evaporation pulls the water column upwards and gravity pulls it down, so the water column is under tension
6. The adhesion of water molecules to the sides of the xylem vessels stops the column breaking

Question 11

What does phloem transport?

Answer 11

Organic compounds

Question 12

What is transported through plants in phloem tissue?

Answer 12

Sugars and other organic compounds are transported

Question 13

Why is phloem tissue also arranged in tubes?

Answer 13

So the solutions of sugar, etc. can move through them easily

Question 14

What is translocation?

Answer 14

The movement of carbohydrates and other organic compounds in plants

Question 15

Where does translocation occur?

Answer 15

In the sieve tubes of the phloem tissue

Question 16

What do the companion cells next to the sieve tubes do?

Answer 16

Believed to actively transport sugar into the sieve tubes, and then water follows by osmosis