Transport Systems (Roots and Stems).

Question 1

What are xylem and phloem made from?

Answer 1

Xylem and phloem are made from cells which are joined end to end, forming continuous tubes from the roots to the leaves.

Question 2

What are the xylem and phloem known as together?

Answer 2

Together, the xylem and phloem are known as vascular bundles.

Question 3

What do xylem vessels transport?

Answer 3

Xylem vessels transport water and dissolved mineral salts from the soil to the leaves.

Question 4

What do phloem tubes transport?

Answer 4

Phloem vessels transport food from the leaves to the rest of the plant.

Question 5

The protoplasm (cytoplasm and nucleus) of the xylem cells is destroyed, leaving only the cell walls. This creates a lumen. Define lumen.

Answer 5

The lumen is a hollow, narrow space which allows the upward movement of water by capillary action.

Question 6

What is capillarity?

Answer 6

Capillarity is the rise of liquid in a thin tube against the force of gravity.

Question 7

Besides transport of water, what else do the xylem vessels do for the plant?

Answer 7

Besides transport of water, the xylem vessels provide support to the plants.

Question 8

What do the outer walls of the xylem contain and what does it do?

Answer 8

The outer walls of the xylem contain lignin, which makes the vessels strong enough to be able to support the plant.

Question 9

The xylem vessels have pits, which allow for what?

Answer 9

The xylem vessels have pits which allow sideways movement of water.

Question 10

Where are xylem vessels located?

Answer 10

• Location = Found in the roots, stems, and leaves.

Question 11

What are the 7 structures of xylem vessels?

Answer 11

Made from xylem cells:

• Joined end to end.
• No end walls.
• Elongated.
• Hollow tubes.
• No living contents (cytoplasm and nucleus).
• Has lignin spirals to strengthen the cell wall.
• Have pits that allow sideways movement of water.

Question 12

What are the 2 mechanisms of xylem vessels?

Answer 12

• The movement of water is in one direction only.

- The transport of materials in the xylem is a passive process.

Question 13

What is the structure of phloem tubes?

Answer 13

Made from living cells called sieve tube cells which are joined end to end forming long tubes.

Question 14

What is the mechanism of phloem tubes?

Answer 14

Movement of the substances is both up from the storage organ to growing flowers and leaves and down from the leaves to roots where it can be stored.

Question 15

Give the function to the part of the root: Epidermis.

Answer 15

It provides a protective barrier against mechanical injury and infection.

Question 16

Give the function to the part of the root: Root hair.

Answer 16

This is a long extension of a root epidermal cell that increases surface area for the uptake of water and mineral ions.

Question 17

Give the function to the part of the root: Vascular cylinder.

Answer 17

Located at the centre of the root and is composed of xylem and phloem.

Question 18

Give the function to the part of the root: Xylem.

Answer 18

Non-living vascular tissue that transports water and minerals throughout the plant.

Question 19

Give the function to the part of the root: Phloem.

Answer 19

Living vascular tissue that transports dissolved sugars such as sucrose and other organic substances around the plant.

Question 20

Give the function to the part of the root: Cortex.

Answer 20

The cells of the cortex support the plant and stores food.

Question 21

What is found on the outside of the epidermis and what does it do?

Answer 21

A tough, waxy substance, called the cuticle, is found on the outside of the epidermis and prevents water loss.

Question 22

What is the function of parenchyma cells?

Answer 22

Parenchyma cells give support to the plant and store substances such as starch and proteins.

Question 23

A root hair cell has a long, thin extension. Why?

Answer 23

A root hair cell has a long, thin extension that penetrates between soil particles, thereby increasing the surface area for the absorption of water and mineral ions.

Question 24

How do the water molecules enter the root hair cells?

Answer 24

The water molecules enter the root hair cells by the process of osmosis.

Question 25

Define osmosis.

Answer 25

Osmosis is the movement of water molecules from a region of high concentration to a region of low concentration through a semi-permeable membrane.

Question 26

Diagrams to Study:

Answer 26

• Demo - capillary tube.
• Xylem Vessels.
• Phloem Tubes.
• Roots.
• Stem.
• Figure 4.1.5 Page 48.

Question 27

Water is attracted to the walls of xylem, explain further.

Answer 27

• Water is attracted to the walls of xylem (adhesion forces) and to each other (cohesive forces).

Question 28

What are the end walls of the sieve tubes like?

Answer 28

The end walls of the sieve tubes are perforated, forming sieve plates which allow communication between sieve tube cells.

Question 29

What is ringbarking?

Answer 29

Ringbarking is the complete removal of a strip of bark from around the entire circumference of either a branch or trunk of a woody plant.

Question 30

What is translocation?

Answer 30

Translocation is the movement of dissolved sugars that are produced during photosynthesis.