Biology questions, chapter 4

Nama / NameKelas / ClassTarikh / Date

Transport in Plants

44 marks. Use Practice to check each answer as you go, or Exam to answer everything against the clock first.

Section A: objective questions

15 marks

Choose the best answer for each question.

Question 1

Which of the following is a non-vascular plant?

Hibiscus
Moss
Balsam
Sunflower

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Algae and mosses have no xylem or phloem, so they are non-vascular. The others are flowering (vascular) plants.

For the teacher: Remembering, low difficulty, standard 4.1.1

Textbook p. 76

Question 2

Which substance thickens the walls of xylem vessels?

Pectin
Starch
Lignin
Sucrose

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Uneven lignin thickening strengthens xylem vessels and supports the plant.

For the teacher: Remembering, low difficulty, standard 4.1.2

Textbook p. 77

Question 3

Which structure supplies ATP for the active transport of sucrose into a sieve tube?

Companion cell
Tracheid
Sieve plate
Xylem vessel

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Companion cells contain many mitochondria that produce ATP for loading sucrose into the sieve tube.

For the teacher: Remembering, low difficulty, standard 4.1.3

Textbook p. 78

Question 4

Root hair cells have a lower water potential than the soil water. What causes this?

Water is pumped out of the vacuole
Sucrose enters from the phloem
Starch is stored in the nucleus
Mineral ions are actively pumped into the vacuole

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Active uptake of mineral ions lowers the water potential of the cell sap, so water enters by osmosis.

For the teacher: Understanding, medium difficulty, standard 4.2.1

Textbook p. 80

Question 5

Cohesion force in the xylem is the attraction between

water molecules and the xylem wall
water molecules and other water molecules
mineral ions and water molecules
sucrose and water molecules

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Cohesion is between water molecules; adhesion is between water molecules and the xylem wall.

For the teacher: Remembering, low difficulty, standard 4.2.1

Textbook p. 81

Question 6

A plant is set up as in the transpirational pull experiment. Some leaves are then removed. What happens to the water level in the side tube?

It falls more slowly because transpirational pull is reduced
It rises because root pressure increases
It stays the same because adhesion stops
It falls faster because there are fewer leaves

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Fewer leaves means fewer stomata and a lower rate of transpiration, so less water is pulled up and the level falls more slowly.

For the teacher: Applying, medium difficulty, standard 4.2.1

Textbook p. 83

Question 7

Guttation is the release of

water vapour through the stomata
sucrose through the sieve plates
water droplets through the ends of leaf veins
oxygen through the lenticels

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Guttation releases water droplets at special structures at the end of leaf veins, caused by high root pressure.

For the teacher: Remembering, low difficulty, standard 4.2.2

Textbook p. 84

Question 8

Which statement is true of transpiration but NOT of guttation?

It loses water from the leaf
It occurs through stomata
It happens at night
It releases water rich in minerals

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Transpiration loses water vapour through stomata. Guttation uses special structures at vein ends, happens at night and releases mineral-rich water.

For the teacher: Analysing, medium difficulty, standard 4.2.3

Textbook p. 85

Question 9

Translocation is the transport of organic substances in the

phloem
xylem
cortex
epidermis

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Translocation takes place in the phloem, from the leaves to other parts.

For the teacher: Remembering, low difficulty, standard 4.3.1

Textbook p. 86

Question 10

In translocation, water enters the sieve tube from the xylem. Why?

Hydrostatic pressure in the xylem is high
Transpiration is high in the sieve tube
Sucrose lowers the water potential in the sieve tube
The sieve plates are blocked

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Sucrose loaded into the sieve tube lowers its water potential, so water moves in from the xylem by osmosis, raising hydrostatic pressure.

For the teacher: Understanding, medium difficulty, standard 4.3.3

Textbook p. 87

Question 11

A ring of bark including the phloem is removed from a woody stem. After three weeks, what is seen?

The part below the ring swells and the part above shrinks
The whole stem wilts immediately because the xylem is cut
Both parts swell equally
The part above the ring swells because sucrose collects there

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The phloem is removed, so sucrose from the leaves cannot pass downward and builds up above the ring. The xylem is left intact.

For the teacher: Applying, medium difficulty, standard 4.3.3

Textbook p. 88

Question 12

Which plant is used to remove radioactive caesium and strontium from soil?

Water lettuce
Water spinach
Water hyacinth
Sunflower

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Sunflowers are hyperaccumulators used after the Chernobyl accident.

For the teacher: Remembering, low difficulty, standard 4.4.2

Textbook p. 90

Question 13

Which cells are dead at maturity and have no cytoplasm?

Companion cells
Sieve tubes
Xylem vessels
Spongy mesophyll cells

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Xylem vessels are dead, empty cells joined end to end. Phloem cells (sieve tubes and companion cells) are living.

For the teacher: Remembering, low difficulty, standard 4.1.2

Textbook p. 77

Question 14

By which process does water from the soil enter the root hair cells?

Osmosis
Active transport
Translocation
Transpiration

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Water diffuses from the soil, where its water potential is higher, into the root hair cells by osmosis.

For the teacher: Remembering, low difficulty, standard 4.2.1

Textbook p. 80

Question 15

Which structure in the endodermis is not permeable to water and so blocks the apoplast pathway?

Pit
Casparian strip
Sieve plate
Lignin thickening

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The Casparian strip in the endodermis cell walls blocks the apoplast route, so water must go through the cytoplasm (simplast pathway).

For the teacher: Remembering, low difficulty, standard 4.2.1

Textbook p. 81

Section B: structured questions

29 marks

Answer all questions.

Question 16

Xylem vessels and tracheids are dead at maturity.

[1 mark] (a)State the main function of xylem.

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Transport water and mineral salts from the roots to the stems and leaves1

Tick each point you got.

[4 marks] (b)State two structural adaptations of xylem vessels or tracheids and the function of each.

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Any of these points, up to 4 marks

No cytoplasm / empty cells joined end to end into a continuous tube [1] so water flows without obstruction [1]2
Walls thickened with lignin [1] to strengthen and prevent collapse under tension, and to support the plant [1]2
Pits in tracheids [1] let water move to neighbouring cells [1]2

Tick each point you got.

For the teacher: Understanding, low difficulty, standard 4.1.2

Textbook p. 77

Question 17

Diagram 1 shows how sucrose is transported from a leaf to a fruit.

Phloem and xylem with a leaf cell, companion cell, sieve tube, sieve plates and a fruit — Diagram 1

[1 mark] (a)Name the process shown in Diagram 1.

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Translocation1

Tick each point you got.

[2 marks] (b)How is sucrose moved from the leaf cell into the sieve tube?

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Active transport [1]1
Through the companion cell, using ATP [1]1

Tick each point you got.

[2 marks] (c)Explain why water moves from the xylem into the sieve tube.

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Sucrose lowers the water potential in the sieve tube [1]1
Water diffuses in from the xylem by osmosis [1]1

Tick each point you got.

[1 mark] (d)What forces the phloem sap along the sieve tube to the fruit?

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High hydrostatic pressure in the sieve tube1

Tick each point you got.

For the teacher: Analysing, medium difficulty, standard 4.3.3

Textbook p. 87

Question 18

Compare guttation and transpiration.

[1 mark] (a)State one similarity.

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Any 1 points

Both occur through the leaf1
Both cause permanent loss of water from the plant1

Tick each point you got.

[2 marks] (b)State two differences.

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Any 2 points

Guttation at night and early morning; transpiration on hot, windy days1
Guttation releases liquid droplets; transpiration releases water vapour1
Guttation through special structures at vein ends; transpiration through stomata1
Guttation due to high root pressure; transpiration controlled by stomata1
Guttation releases mineral-rich water; transpiration pure water1

Tick each point you got.

[1 mark] (c)Predict one effect on a plant if transpiration did not occur.

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Any 1 points

Temperature rises and enzymes denature1
Minerals not transported to leaves1
The plant wilts and may die1

Tick each point you got.

For the teacher: Analysing, low difficulty, standard 4.2.3

Textbook p. 85

Question 19

A balsam stem is cut 5 cm above the soil and attached to a water manometer with a rubber tube. The joint is sealed with petroleum jelly. After 30 minutes the water level in the manometer arm has risen.

[1 mark] (a)Why is petroleum jelly applied to the joint?

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To make the connection airtight1

Tick each point you got.

[1 mark] (b)Compare the water potential of the root cells with that of the soil water.

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Root cells have a lower water potential than the soil water1

Tick each point you got.

[1 mark] (c)State the inference from the experiment.

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Root pressure pushes water from the soil up the stem1

Tick each point you got.

[2 marks] (d)Why is root pressure alone not enough for a tall tree?

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Root pressure is too weak to lift water to the tall shoots [1]1
Capillary action and transpirational pull are needed [1]1

Tick each point you got.

For the teacher: Applying, medium difficulty, standard 4.2.1

Textbook p. 82

Question 20

A farmer next to an industrial area digs a trench to bring irrigation water to his crops and plants water hyacinths in it.

[1 mark] (a)What is the method of using plants to treat polluted water called?

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Phytoremediation1

Tick each point you got.

[2 marks] (b)Justify the farmer's action.

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Water hyacinth roots absorb heavy metals and nutrients such as ammonia from the water [1]1
The water reaching the crops is cleaner, so crops are safer and healthier [1]1

Tick each point you got.

[1 mark] (c)Suggest one problem if the water hyacinths are not managed.

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Any 1 points

They multiply and cover the water, depleting oxygen1
Fish and other organisms cannot survive or breed1

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[1 mark] (d)Name one other plant used for phytoremediation and the pollutant it removes.

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Any 1 points

Sunflower: zinc, lead, caesium, strontium1
Water spinach: mercury, cadmium1
Water lettuce: heavy metals and nutrients1

Tick each point you got.

For the teacher: Evaluating, high difficulty, standard 4.4.3

Textbook p. 91

Question 21

State whether each statement is about xylem or phloem.

[1 mark] (a)Has living cells with cytoplasm.

AXylemBPhloem

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Phloem

[1 mark] (b)Has lignin thickening in the walls.

AXylemBPhloem

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Xylem

[1 mark] (c)Has sieve plates with pores.

AXylemBPhloem

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Phloem

[1 mark] (d)Carries water and mineral salts.

AXylemBPhloem

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Xylem

For the teacher: Understanding, low difficulty, standard 4.1.3

Textbook p. 78

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