1

1. What process creates the low pressures needed for the movement of water upwards in the

xylem?

A. Active translocation

B. Active transport

C. Evaporation of water from mesophyll of leaves

D. Evaporation of water from guard cells (Total 1 mark)

2. (a) Outline three adaptations of xerophytes that allow them to conserve water.

......................................................................................................................................

......................................................................................................................................

......................................................................................................................................

......................................................................................................................................

......................................................................................................................................

...................................................................................................................................... (3)

(b) (i) Name one nitrogenous waste product of birds.

............................................................................................................................ (1)

(ii) Suggest an adaptive advantage of this waste product in relation to their habitat.

............................................................................................................................

............................................................................................................................ (1)

2

(c) Explain the main role of each of the following in maintaining the water balance of the

body.

(i) Loop of Henlé

............................................................................................................................

............................................................................................................................

............................................................................................................................ (1)

(ii) Collecting duct

............................................................................................................................

............................................................................................................................

............................................................................................................................ (1)

(iii) ADH

............................................................................................................................

............................................................................................................................

............................................................................................................................ (1)

(Total 8 marks)

3. What treatment is most likely to lead to germination?

A. Soaking the seeds in a solution of gibberellins

B. Increasing CO2 concentration

C. Increasing light intensity

D. Dehydrating the seeds (Total 1 mark)

3

4. (a) State two types of meristem found in plants.

.....................................................................................................................................

..................................................................................................................................... (1)

(b) Outline two differences in structure between monocotyledonous and dicotyledonous

plants.

Structure Monocotyledonous Dicotyledonous

(2)

(c) State two methods by which terrestrial plants support themselves.

.....................................................................................................................................

..................................................................................................................................... (1)

4

(d) Explain how auxin controls the response of a plant to light.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

(Total 7 marks)

5. Up to two additional marks are available for the construction of your answers. (2)

(a) Outline the various means of transfer of different types of molecules through the plasma

membrane. (4)

(b) Describe the transport of water through an angiosperm root system. (6)

(c) Explain the homeostatic control of water balance in the human body. (8)

(Total 18 marks)

6. Up to two additional marks are available for the construction of your answers. (2)

(a) Draw and label a diagram of a dicotyledonous animal-pollinated flower as seen with the

naked eye and a hand lens. (5)

(b) Describe how meiosis results in an enormous genetic variety in the production of pollen. (5)

(c) Using the theory of natural selection, explain how new species of dicotyledonous plants

develop. (8)

(Total 20 marks)

5

7. (a) State two ways in which plant productivity can be measured.

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(b) Outline the effect of carbon dioxide concentration on plant productivity.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(Total 4 marks)

8. Which is an adaptation of hydrophytes?

A. Water storage tissue

B. Shallow but widely spreading roots

C. Reduced thickness of cuticle

D. Large numbers of stomata in the lower epidermis (Total 1 mark)

9. Which process starts the germination of a starchy seed.

A. Production of gibberellin

B. Absorption of water

C. Maltose is converted to glucose water

D. Production of amylase (Total 1 mark)

10. The mold Penicillium expansum causes serious crop loss of apples and pears during storage and

packing. The graphs below show the density of P. expansum spores on normal skin, damaged

6

skin and lenticels (small air pores allowing gaseous exchange) of apples. The experiments show

the results at two humidity levels over a four day period.

High humidity Low humidity

1000

100

10

1

1000

100

10

1

9648241240 9648241240

Time / h Time / h

Log

spo

res

/ cm

10

2

Log

spo

res

/ cm

10

2Key: density of spore on normal skin

density of spore on damaged skindensity of spore on lenticels

[Source: This article was published in Physiological and Molecular Plant Pathology, Volume 67, Issue 1, authors

Achour Amiri, Danielle Cholodowski and Gilbert Bompeix, “Adhesion and germination of waterborne and airborne

conidia of Penicillium expansum to apple and inert surfaces”, pp. 40-48, copyright Elsevier (2005).]

(a) State the time taken for spores on the skin to reach a density of 100 spores/cm2 at high

humidity.

...................................................................................................................................... (1)

(b) Compare the density of spores on normal skin with spores on lenticels for apples stored at

high humidity.

......................................................................................................................................

......................................................................................................................................

......................................................................................................................................

...................................................................................................................................... (2)

7

(c) Discuss whether apples should be stored at high humidity or low humidity.

......................................................................................................................................

......................................................................................................................................

......................................................................................................................................

......................................................................................................................................

......................................................................................................................................

...................................................................................................................................... (3)

(Total 6 marks)

11. Sweet pepper (Capsicum annuum) is an important widespread agricultural crop. Scientists

studied the transport and distribution of sodium in sweet pepper by growing plants in sodium

chloride solutions.

The graph below shows the sodium ion concentration in plant parts of sweet pepper grown in 15

mM sodium chloride for three weeks.

Sodium ion concentration /

30

28

26

24

22

20

18

16

14

12

10

8

6

4

2

0

Root Leaves Fruit Stem

Plant Part

mM kg–1

[Source: M Blom-Zandstra et. al., “Sodium fluxes in sweet pepper exposed to varying sodium concentrations”,

Journal of Experimental Botany (1 November 1998), vol. 49, issue 328, pp. 1863–1868,

by permission of Oxford University Press]

8

(a) (i) State the concentration of sodium ions in fruits.

........................................................................................................................... (1)

(ii) Calculate the percentage increase in sodium ion concentration between root and

stem.

........................................................................................................................... (1)

(b) Suggest why a high sodium ion concentration in the cells of the stem is important in

providing support to this type of plant.

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (1)

(c) State one possible use of sodium in plants.

.................................................................................................................................... (1)

(d) Scientists also found that the concentrations of sodium ion in cells of the stem and in

xylem sap were the same. Explain why this led the scientists to believe there was no

active transport between xylem and stem.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (2)

(e) Suggest one possible method of transport of sodium ions between xylem and stem.

.................................................................................................................................... (1)

9

The graph below shows the sodium ion concentration of the xylem sap in relation to the

distance from the base. Two experiments were performed.

Experiment 1: plants grown in 15 mM sodium chloride solution only

Experiment 2: plants grown in 15 mM sodium chloride solution and then transferred to a

sodium-free solution for an extra week

Key: experiment 1 experiment 2

Sodium ion concentration /

mM

18

16

14

12

10

8

6

4

2

0 40 60 80 100 120 140

Distance from base / arbitrary units

[Source: M Blom-Zandstra et. al., “Sodium fluxes in sweet pepper exposed to varying sodium concentrations”,

Journal of Experimental Botany (1 November 1998), vol. 49, issue 328, pp. 1863–1868,

by permission of Oxford University Press]

(f) State the relationship between sodium ion concentration and distance from the base of the

stem in experiment 1.

.................................................................................................................................... (1)

(g) (i) State the sodium concentration when the stem is 50 arbitrary units from the base in

plants for each of the following.

Experiment 1: .................................................................................................

Experiment 2: ................................................................................................. (1)

10

(ii) Explain the difference in the sodium ion concentration in this part of the stem in

plants of experiment 1 and experiment 2.

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

........................................................................................................................... (2)

(h) Compare the distribution of sodium ions in the stems of plants in both experiments.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (3)

Water transported in xylem is transpired through stomata in leaves. The electron micrograph

shows one stoma of the lower epidermis of the leaf of a Simon bamboo (Arundinaria simonii).

Its magnification is 3000.

[Source: Courtesy of Professor Zulma E Rúgolo, Instituto Darwinion, Buenos Aires, Argentina]

(i) (i) Draw a line showing the maximum length of the stomatal pore. (1)

11

(ii) Calculate the real size of the stomatal pore. Show your working.

........................................................................................................................... (1)

(j) Explain two abiotic factors that affect transpiration rate in this leaf.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (2)

(Total 18 marks)

12. A plant has a waxy cuticle, reduced leaves, reduced number of stomata, and CAM physiology.

What type of plant could this be?

A. A hydrophyte

B. A filicinophyte

C. A bryophyte

D. A xerophyte (Total 1 mark)

12

13. Up to two additional marks are available for the construction of your answers. (2)

(a) Draw and label a diagram showing the structure of a glomerulus and associated nephron. (4)

(b) Explain how water balance is maintained in the blood. (8)

(c) Describe the process of water uptake and movement in roots. (6)

(Total 20 marks)

14. Up to two additional marks are available for the construction of your answers. (2)

(a) Draw a diagram of a dicotyledonous animal-pollinated flower as seen with the naked eye

and hand lens. (4)

(b) Outline the movement of water in plants from root to leaf, including the effects of abiotic

factors on the rate of transport. (6)

(c) Explain photophosphorylation in terms of chemiosmosis. (8)

(Total 20 marks)

15. In flowering plants, which of the following helps seed dispersal?

A. Bees

B. Pollen

C. Mammals

D. Germination (Total 1 mark)

13

16. Potatoes are stem tubers. They are swollen underground stems with buds. When potatoes are

harvested they are dormant and their buds will not sprout. The beginning of sprouting is

difficult to predict, it changes the nutritional value of the potato and results in serious financial

losses in the potato industry. Plant physiologists wanted to determine the role of gibberellic

acid, a plant growth regulator (plant hormone), on sprouting in potatoes.

Potatoes were treated with four different inhibitors of gibberellic acid synthesis (CCC, AMO,

ANC and TET). Their effects were observed on sprouting at different times after harvesting.

The results are shown below.

Sprouting / %

Control CCC AMO ANCTET

Treatment

Time/day140168

182

100

90

80

70

60

50

40

30

20

10

0

[Source: Reprinted from Jeffrey C. Suttle, “Involvement of endogenous gibberellins in potato tuber dormancy and

early sprout growth: a critical assessment”, Journal of Plant Physiology, vol. 161, p. 157, © 2004

with permission from Elsevier]

(a) Calculate the difference between sprouting in potatoes treated with ANC at 140 and 168

days.

...................................................................................................................................

...................................................................................................................................

................................................................................................................................... (1)

14

(b) Compare the effects of CCC and AMO on the sprouting of the potatoes.

...................................................................................................................................

...................................................................................................................................

...................................................................................................................................

...................................................................................................................................

...................................................................................................................................

................................................................................................................................... (3)

(c) Deduce the effects of gibberellic acids on sprouting in potatoes.

...................................................................................................................................

...................................................................................................................................

...................................................................................................................................

................................................................................................................................... (2)

(d) Suggest a treatment which could be used to delay sprouting in potatoes.

...................................................................................................................................

................................................................................................................................... (1)

(Total 7 marks)

15

17. Plants that grow in the desert have many adaptations that enable them to cope with full sunlight

and low water availability, such as thicker leaves with reduced surface area. Researchers have

also observed that leaf pubescence (presence of white leaf surface hairs) may be another

adaptation to dry environments. A study was done to evaluate the effects of leaf pubescence on

two species of Californian plants, Encelia farinosa, a desert species with pubescent leaves and

Encelia californica, a native of the moist coast with non-pubescent leaves.

The graph below shows the absorption spectrum of intact leaves of both species in the

photosynthetically active spectrum between the wavelengths 400 nm (blue light) and 800 nm

(red light) of light.

Absorption

/ %

100

90

80

70

60

50

40

20

10

0

400 450 500 550 600 650 700 750 800

Blue Green Yellow Orange Red

Wavelength / nm

Key:

E. californica

E. farinosa

30

[Source: From J. Ehleringer et al., “Leaf Pubescence: Effects on Absorptance and Photosynthesis in a Desert Shrub”, Science (23

April 1976), vol. 192, issue 4237, pp. 376-377. Reprinted with permission from AAAS]

16

(a) Calculate the difference in absorption between E. farinosa and E. californica at 600 nm.

....................................................................................................................................

.................................................................................................................................... (1)

(b) Suggest a possible explanation for the decrease in absorption at 550 nm for E. californica.

....................................................................................................................................

.................................................................................................................................... (1)

The following graph shows the rate of CO2 uptake of three leaves of Encelia farinosa with

different absorbance coefficients (x) (proportion of light absorbed) which is related to the degree

of pubescence of the leaf. The higher the coefficient the more light is absorbed.

Rate of CO2 uptake /

n mol CO2 cm–2 sec–1

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0

x = 0.82

x = 0.65

x = 0.53

0 50 100 150 200 250

Light intensity / mmol cm–2 sec–1

[Source: From J. Ehleringer et al., “Leaf Pubescence: Effects on Absorptance and Photosynthesis in a Desert Shrub”, Science (23

April 1976), vol. 192, issue 4237, pp. 376-377. Reprinted with permission from AAAS]

17

(c) Using the graph above, compare the maximum CO2 uptake of E. farinosa at absorbance

coefficients 0.82 and 0.53.

....................................................................................................................................

.................................................................................................................................... (1)

(d) (i) Using the data, deduce the relationship between pubescence and light absorption.

..........................................................................................................................

.......................................................................................................................... (1)

(ii) Evaluate the relationship of leaf pubescence and CO2 uptake.

..........................................................................................................................

.......................................................................................................................... (1)

(e) Suggest how natural selection may have caused the difference in leaf pubescence between

E. farinosa and E. californica.

....................................................................................................................................

.................................................................................................................................... (1)

18

Further research was carried out to evaluate the relationship between leaf pubescence during the

growing season of E. farinosa and its water use efficiency. Water use efficiency is defined as

the amount of CO2 uptake divided by the amount of water lost by transpiration from the leaf.

The graph below shows the seasonal change in leaf pubescence and water use efficiency of E.

farinosa. The period of maximum growth is indicated on the graph. During the course of the

year the optimum temperature for photosynthesis remains at 30 C while the air temperature

fluctuates from a high of 38 C in the summer months (May–September) to a low of 8 C during

the winter months (December–February).

Wat

er u

se e

ffci

ency

/ a

rbit

rary

unit

s

6

5

4

2

1

0 M J J A S O N D J F M A M

0.35

0.30

0.25

0.20

0.15

0.10

0.05

0.00

Pu

bescen

ce Thick

ness /m

m

Key:

Water use effciency

Pubescence thickness

Time of the year / month maximum growth period

new leaves emerge

3

[Source: Ecology by William K. Smith and Park S. Nobel. Copyright 1977 by Ecological Society of America. Reproduced with

permission of Ecological Society of America in the format of CD-Rom via Copyright Clearance Center.]

(f) State the month with the highest water use efficiency.

.................................................................................................................................... (1)

(g) Outline the changes in leaf pubescence of E. farinosa during the year.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (2)

19

(h) Analyse the change in the level of water use efficiency between July and December for E.

farinosa.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (2)

(Total 11 marks)

18. Which direction does the phloem transport materials?

A. Up the plant at night and down the plant during the day

B. Up and down the plant all the time

C. Up the plant only

D. Down the plant only (Total 1 mark)

19. Xerophytes and hydrophytes are adapted to their environments. Which pair of adaptations is

correct?

Xerophytes Hydrophytes

A. Air spaces in roots Water storage in roots

B. No stomata No stomata

C. Stomata in pits Thin or no cuticle

D. Thick cuticle Stomata in pits

(Total 1 mark)

20

20. Discuss the practice of intense monoculture in present-day agriculture.

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

............................................................................................................................................... (Total 7 marks)

21

21. In order to prevent transfer of pollen from an anther of one plant to the stigma of the same plant

(self-pollination), the sunflower (Helianthus spp) anther sheds its pollen before the stigma is

mature enough to receive it. Early in the morning the anther is exposed by elongation of the

filaments. The anthers open at this time to release their pollen (anthesis). The stigma appears

above the anthers by late afternoon, and by the following morning it is fully receptive.

To see how the filament (F) and the style (S) are affected by light, their lengths were measured

at time intervals starting 12 hours before anthesis ( 12). Some plants were grown in continuous

white light (L24) and some plants grown under cycles of 16 hours white light followed by 8

hours dark (L16/D8). The results are shown in the graph.

[Source: Lobello et al, Journal of Experimental Botany, (2000), 51, pages 1403 1412]

(a) Filaments of the plants grown in continuous white light increased in length by 0.25 mm in

the 28 hours after anthesis. Calculate how much the filaments of the plants grown in

alternating white light and dark increased during the same period.

....................................................................................................................................

.................................................................................................................................... (1)

22

(b) Compare the increase in the length of the style in the plants grown in continuous white

light with those grown in alternating white light and dark.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (2)

The table compares the percentage of ovules that have been fertilized and developed into seeds

in sunflower plants grown under continuous white light with those grown under alternating

light and dark. The numbers represent the mean one standard deviation.

Light treatments Percentage of fertilized ovules

Continuous white light (L24) 11.40 7.76

Alternating light and dark (L16/D8) 58.26 4.06

(c) Explain the differences in the percentages of ovules fertilized using the data in the graph

about the growth of filaments and styles.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (3)

23

(d) Explain how standard deviation (SD) shown in this table can be used to help in

comparing the effect of light treatments on the fertilization of ovules.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (3)

To analyse the effect of growth regulators on filament elongation, further experiments were

performed in the dark, white light and red light. The flowers were treated with auxin or with

gibberellic acid and compared to a control with no growth regulator. The results are shown in

the bar chart below.

24

(e) Identify, with reasons, which factors promote and which factors inhibit the elongation of

filaments.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (3)

(f) Explain the disadvantages to a plant of self-pollination.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (2)

(Total 14 marks)

22. What conditions will cause the highest rate of transpiration in a well-watered, mesophytic plant?

A. Hot, humid with bright sunshine and still air

B. Low humidity, hot, bright sunshine and windy

C. Windy, hot, cloudy and humid

D. Windy, bright sunshine, humid and cool (Total 1 mark)

25

23. Which structures are found in coniferophytes? ( = present and = absent)

Roots Stems Leaves Flowers Seeds

A.

B.

C.

D.

(Total 1 mark)

24. What is the apoplastic route for water from the soil to the endodermis of roots?

A. Cell walls of epidermis cell walls of cortex endodermis

B. Cell walls of root hair cells cytoplasm of cortex endodermis

C. Cytoplasm of root hair cells cytoplasm of cortex endodermis

D. Cell walls of root hair cells cell walls of epidermis endodermis (Total 1 mark)

25. (a) State two adaptations of insect-pollinated flowers.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(b) Define the term net assimilation rate.

.....................................................................................................................................

..................................................................................................................................... (1)

26

(c) Predict what will happen to the flowering process of a short day plant if the minimal dark

period is interrupted by brief exposure to light.

.....................................................................................................................................

..................................................................................................................................... (1)

(Total 4 marks)

26. Which of the following help(s) in supporting a terrestrial woody plant?

I. Xylem tissue

II. Turgor pressure

III. Phloem tissue

A. I only

B. I and II only

C. II and III only

D. I, II and III (1)

27

27. Use and conservation preferences for savanna trees were investigated in a West African country.

Residents from different villages evaluated the importance of 20 woody species for eight

different uses: edible fruits, vegetable sauce, construction, firewood, medicine, commerce, field

trees and conservation. The following data is based on answers from 200 residents.

Adansonia digitata

Atzelia africana

Annona senegalensis

Balanites zegyptiaca

Bombax costatum

Detarium microcarpum

Diospyros mespiliformis

Ficus sycomorus

Gardenia erubescens

Lannea microcarpum

Parkia biglobosa

Pericopsis taxiflora

Piliostigma thonningii

Plerocarpus erinaceus

Sterculia setigera

Strychnos spinosa

Tarnarindus indica

Vitellaria paradoxa

Vitext doniana

Ximenia africana

20

01

50

10

05

00

20

01

50

10

05

00

20

01

50

10

05

00

20

01

50

10

05

00

20

01

50

10

05

00

20

01

50

10

05

00

20

01

50

10

05

00

20

01

50

10

05

00

Number of responses

Ediblefruits

Vegetablesauce

Construction Firewood Medicine Commerce Conservationpriority

Fieldtrees

Key: do not know not important moderately important very important

[Source: Economic Botany; Kristensen and Lykke, reprinted by permission from Economic Botany, vol. 57 (2), pages 203–217,

Kristensen and Lykke. Copyright 2003, The NewYork Botanical Garden, Bronx, New York]

(a) Identify the most important tree species to the villagers.

..................................................................................................................................... (1)

(b) State the category of use for which villagers have most difficulty in finding useful

species.

..................................................................................................................................... (1)

28

(c) Compare the usefulness of species in providing edible fruit with their usefulness for

vegetable sauce.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(d) Determine the percentage of species that are valued entirely as “very important” in at

least three categories.

.....................................................................................................................................

..................................................................................................................................... (1)

(e) Suggest a property of the wood from P. erinaceus that makes it one of the preferred

species for use in building houses.

.....................................................................................................................................

..................................................................................................................................... (1)

(Total 6 marks)

29

28. Describe how flowering is controlled in long day plants (LDP)

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

............................................................................................................................................... (Total 4 marks)

30

29. Discuss the ethical issues surrounding the use of biological and chemical pest control.

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

............................................................................................................................................... (Total 6 marks)

30. State one structural feature of each of the following plant groups: bryophytes,

angiospermophytes and coniferophytes. (Total 3 marks)

31

31. Kochia (Kochia scoparia) is a common weed in the Great Plains of the United States and

Canada. Kochia affects crops by reducing the yield of wheat and corn. Kochia is difficult to

control because of its leaf characteristics. The leaves either prevent herbicide contact or the

herbicide spray droplets roll off the leaf. Chemicals known as surfactants are detergents which

help to aid the retention of herbicides on the leaves of the weeds. Research was undertaken to

study the influence of surfactants on the effectiveness of three herbicides in aiding the control of

Kochia.

The table below shows the percentage biomass reduction of Kochia using three herbicides with

different surfactants.

Percentage Biomass Reduction

Surfactant Bromoxynil 2,4-D-amine Glyphosphate

No surfactant 95 27 21

Allinol 97 40 9

Mon 0818 95 44 82

Oxysorbic 92 43 71

R-11 94 40 26

[Source: Harbour, et al, Weed Science, (2003), 51, page 430]

(a) (i) State which herbicide was most effective in controlling Kochia with no surfactant.

........................................................................................................................... (1)

(ii) State which surfactant was least effective in controlling Kochia.

........................................................................................................................... (1)

(iii) Calculate the mean percentage biomass reduction when using surfactants with

glyphosphate.

...........................................................................................................................

........................................................................................................................... (1)

32

(b) Using the data in the table, discuss the advice that should be given to farmers on the use

of surfactants.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

(Total 6 marks)

32. Explain the process of water uptake and transport by a plant. (Total 8 marks)

33. Draw a labelled diagram to show the external parts of a named dicotyledonous plant. (Total 5 marks)

34. Explain how roots absorb water and then transport it to the xylem, noting any special

adaptations that help these processes to occur. (Total 9 marks)

33

35. Which of the following is a correct comparison of the bryophytes and the filicinophytes?

Bryophytes Filicinophytes

A. Has a waxy cuticle No waxy cuticle

B. Has true leaves Has scales

C. Has rhizoids Has roots

D. Has woody tissue No woody tissue

(1)

36. The leaves of the plant Tree of Heaven (Ailanthus altissima L.) have been reported to contain

compounds that act as both herbicides and pesticides. Chemicals were extracted from the leaves

and the bioactivity of these was tested on the growth of alfalfa seedlings. The results are shown

in the bar chart below. Negative values for growth inhibition indicate increased growth.

Key:

Light

Dark

60

50

40

30

20

10

0

–10

–20

–300.16 8 40 200

Concentration of extract / ppm

% growth inhibitioncompared with control

[Source: adapted from Tsao et al, BMC Ecology, (2002), 2, pages 1–6]

(a) (i) Determine the concentration of the extract that had the greatest difference between

dark and light conditions.

........................................................................................................................... (1)

34

(ii) State the largest percentage growth inhibition for seedlings grown in the light.

........................................................................................................................... (1)

(b) Outline the effect of extract concentration on growth in the dark.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(c) Suggest reasons for testing the bioactivity of the extract on seedlings in the dark and in

the light.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(Total 6 marks)

35

37. (a) Discuss the biological issues surrounding biological and chemical pest control.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (4)

(b) Discuss the use and misuse of antibiotics in livestock production.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

(Total 7 marks)

36

38. (a) (i) Define the term net assimilation rate.

...........................................................................................................................

........................................................................................................................... (1)

(ii) Outline how net assimilation rate can be used to measure plant productivity.

...........................................................................................................................

........................................................................................................................... (1)

(b) Explain how greenhouses are used to improve plant productivity.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (4)

(Total 6 marks)

37

39. (a) Distinguish between plant growth regulators and fertilizers.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(b) Explain the role of auxin in phototropism.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

(Total 5 marks)

38

40. Outline the techniques used in cloning plants by micropropagation.

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

............................................................................................................................................... (Total 4 marks)

39

41. An experiment was carried out to investigate the effect of water stress on cucumber (Cucumis

sativus) seedlings. Cotyledons were detached from four day old seedlings and treated with

polyethylene glycol (PEG), a water absorbing compound. -amylase activity was measured in

cotyledons treated with PEG at concentrations of 0, 20, 30, 40 and 50%. This enzyme catalyses

the conversion of starch into maltose. The mean results are shown in the graph.

0.3

0.2

0.1

0

3210

Duration of treatment / days

β- amylase activity perpair of cotyledons

/ mol maltose minυ –1

[Source: D Todak, et al., (2000), Journal of Experimental Botany, 51, pages 739–745]

(a) Identify the maximum activity of -amylase in the 50% treatment.

..................................................................................................................................... (1)

(b) Compare the -amylase activity in the cotyledons treated with 20% PEG with those

treated with 30% PEG.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

40

(c) Deduce the relative free sugar content of the cotyledons treated with 20% PEG compared

to those treated with 30% PEG.

.....................................................................................................................................

..................................................................................................................................... (1)

(d) Suggest reasons for the change in activity of -amylase during water stress.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(Total 6 marks)

41

42. A nine-year study was carried out on plants that grow in the arctic tundra. The effects of

different environmental factors were studied:

nutrient addition

use of a greenhouse to raise the summer air temperature by 3°C

use of a “fertilized greenhouse” (increased temperature plus nutrient addition)

shade to reduce light by 50%.

The results are shown in the graph below.

1500

1000

500

0

Total biomass / g m –2

C N T NT L

Treatments

Key:

moss

lichen

evergreen

deciduous

grasses

Control (C), nutrient addition (N), greenhouse (T), fertilized greenhouse (NT) and shading (L).

[Source: UNEP, (1995), Global Biodiversity Assessment, Press Syndicate of the University of Cambridge, page 295]

(a) Identify the treatment that produced

(i) the greatest evergreen biomass.

........................................................................................................................... (1)

(ii) the greatest lichen biomass.

........................................................................................................................... (1)

42

(b) Compare the effects of nutrient addition, raising the temperature and shading on the

biomass of deciduous plants.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(c) Suggest reasons for the differences in total biomass of plants in response to the different

treatments.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(Total 6 marks)

43. Compare the structure of bryophytes and angiospermophytes. (Total 5 marks)

44. Describe the metabolic events of germination in a typical starchy seed. (Total 5 marks)

43

45. Fertilization, pollination and seed dispersal all occur during the reproduction of a flowering

plant. In what sequence do these processes occur?

A. Seed dispersal pollination fertilization

B. Fertilization pollination seed dispersal

C. Pollination fertilization seed dispersal

D. Seed dispersal fertilization pollination (Total 1 mark)

46. Explain how the abiotic factors of light, wind and humidity affect the rate of transpiration. (Total 8 marks)

47. (a) Outline the need to maintain biodiversity of wild plants.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(b) Explain how one veterinary technique improves the health of animals.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(Total 4 marks)

44

48. When a farmer sprays a chemical on to crop plants, how does the chemical travel to the roots of

the plants?

A. In the phloem, by active translocation

B. In the phloem, by transpiration pull

C. In the xylem, by transpiration pull

D. In the xylem, by active translocation (Total 1 mark)

49. Glucosinolates are chemicals found in some vegetables, which are responsible for the taste of

horseradish, wasabi and broccoli. There are two types of glucosinolate, aliphatic and indolyl.

They have been found to have many positive health effects, including carcinogen detoxification

and antioxidant properties. Different varieties of broccoli vary in their content of glucosinolates

as shown in the graph below. Researchers have found that 61% of the variation in aliphatic

glucosinolate concentration is due to genetic factors compared with 12% for indolyl

glucosinolates.

25

20

15

10

5

0

Glucosinolateconcentration /

mol g dry mass–1

Brigadier Packman Petro

Variety of broccoli

Key:

progoitrin (aliphatic)glucoraphanin (aliphatic)glucobrassicin (indolyl)

[Source: E H Jeffery et al., Nutrition Today, (2002), 37, page 208)

45

(a) Using the graph, compare the amount of aliphatic glucosinolates among the different

varieties of broccoli.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

(b) Using the data, explain how outbreeding could be used to develop a new variety of

broccoli with increased glucosinolate content.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

(Total 6 marks)

46

50. (a) Outline the roles of auxin in plants.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

(b) (i) State one problem that may be caused by intensive monoculture.

...........................................................................................................................

........................................................................................................................... (1)

(ii) Discuss the biological issues of organic versus non-organic farming methods.

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

........................................................................................................................... (4)

(Total 8 marks)

47

51. Discuss the ethical issues for and against the use of transgenic plants.

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

............................................................................................................................................... (Total 6 marks)

52. The leaves of plants are adapted to absorb light and use it in photosynthesis. Draw a labelled

diagram to show the arrangement of tissues in a leaf. (Total 6 marks)

53. (a) Define the term F1 hybrid vigor.

.....................................................................................................................................

..................................................................................................................................... (1)

48

(b) Describe the advantages of using intensive animal rearing techniques.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

(Total 4 marks)

54. Draw a labelled diagram of a monocotyledonous wind-pollinated flower.

(Total 4 marks)

49

55. Outline the need to maintain wild plants for use in breeding programmes.

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

............................................................................................................................................... (Total 4 marks)

50

56. Explain how manipulation of day length is used in the production of flowers.

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

............................................................................................................................................... (Total 6 marks)

57. (a) Explain the role of auxin in phototropism.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

51

(b) Describe how plant growth regulators can be used commercially to produce fruits without

seeds.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(Total 5 marks)

58. Seed dispersal is important in the migration of plants from one area to another area. Plants

have evolved many methods, both physical and biological, by which to disperse their seeds.

50 maple seeds, which are wind dispersed, were dropped one at a time from two different

heights, 0.54 m and 10.8 m respectively. The histograms below show the distribution of the

distance the maple seeds travelled.

18

16

14

12

10

8

6

4

2

0

18

16

14

12

10

8

6

4

2

0

Numberof seeds

Numberof seeds

Height = 0.54 m Height = 10.8 m

Distance travelled / cm Distance travelled / m

0 to

19

0 to

2.9

20 to

39

3 to

5.9

40 to

59

6 to

8.9

60 to

79

9 to

11.

9

80 to

99

12 to

14.

9

100

to 1

19

15 to

17.

9

120

to 1

39

18 to

20.

9

140

to 1

59

21 to

24

160

to 1

79

over

24

180

to 2

00

2

15

9

17

5 5

4 4

1

7

1 1

3 333

17

[Source: student experiment, Guralnick]

(a) For each height, identify the distance travelled by the greatest number of seeds.

(i) Height = 0.54 m: ...............................................................................................

(ii) Height = 10.8 m: ............................................................................................... (1)

52

(b) State the effect of height on seed dispersal.

..................................................................................................................................... (1)

(c) Suggest two reasons for the effect of the drop height on the distance travelled by the

seeds.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

The following graphs show the rate and timing of seed release from different species of grass in

the same area during the summer.

100

50

0

600

400

200

0

100

50

0

400

300

200

100

0

Festuca rubra

Agrostis stolonifera

Holcus lanatus

Poa trivialis

Rate ofseed fall /numberweek

100 cm

Rate ofseed fall /numberweek

100 cm

Rate ofseed fall /numberweek

100 cm

Rate ofseed fall /numberweek

100 cm

–1

–1

–1

–1

–2

–2

–2

–2

14 21 28 5 12 19 26 2 16 30

14 21 28 5 12 19 26 2 16 30

14 21 28 5 12 19 26 2 16 30

14 21 28 5 12 19 26 2 16 30

June

June

June

June

July

July

July

July

August

August

August

August

[Source: J L Harper, Population Biology of Plants, Academic Press (Harcourt Brace Jovanovich) 1997, page 57]

53

(d) Identify the grass species which produces the most seeds in this area.

..................................................................................................................................... (1)

(e) Identify the grass species which produces the most seeds in June.

..................................................................................................................................... (1)

(f) Compare seed production for all species relative to the timing of their release.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

(g) Suggest two benefits for these plants in the timing of seed release.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

54

Biological seed dispersal is usually dependent on the nutritional content of the seed or fruit. The

following table gives the nutritional content for fruits of different species in temperate and

tropical climates.

Percentage by Dry Weight

Common Name (genus) Protein Lipid Carbohydrate Dispersal

Agents

Temperate

Cranberry (Vaccinium) 3 6 89 Birds

Hawthorn (Crataegus) 2 2 73 Birds

Pin cherry (Prunus) 8 3 84 Birds

Pokeberry (Phytolacca) 14 2 68 Birds

Strawberry (Fragaria) 6 4 88 Birds

Tropical

Bird palm (Chamaedorea) 14 16 55 Birds

Fig (Ficus) 7 4 79 Bats

Mistletoe (Viscum) 6 53 38 Birds

Monkey fruit (Tetragastris) 1 4 94 Monkeys

Wild nutmeg (Virola) 2 63 9 Birds

[Source: H Howe and L Westley, Ecological Relationship of Plants and Animals,

Oxford University Press 1988, page 121]

(h) Compare tropical fruits to temperate fruits in relation to the mean values for lipid,

carbohydrate and protein content.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

55

(i) Explain which fruit would have the highest energy content.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(j) Suggest one advantage and one disadvantage of dispersal of seeds by animals.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

(Total 17 marks)

59. What causes movement of water through the xylem?

A. Active transport in the root tissue

B. Evaporation of water from leaves

C. Active translocation

D. Gravity (Total 1 mark)

60. Outline the role of the phloem in the active translocation of biochemicals. (Total 5 marks)

56

61. Describe the metabolic events of germination in a starchy seed. (Total 5 marks)

62. Explain how abiotic factors affect the rate of transpiration in a terrestrial plant. (Total 8 marks)

63. Draw the structure of a dicotyledenous animal-pollinated flower. (Total 6 marks)

64. What is a characteristic of xerophytes?

A. Absence of roots

B. Absence of vascular tissue

C. Leaves with very small surface area

D. Large number of stomata (Total 1 mark)

65. Which would be an adaptation of xerophytes?

A. Large air spaces

B. Large numbers of stomata

C. Hairs on the leaves

D. Reduced roots (Total 1 mark)

57

66. Describe how water is transported in a plant. (Total 4 marks)

67. (a) State one way in which we make use of domesticated animals.

.....................................................................................................................................

..................................................................................................................................... (1)

(b) (i) Define the term interspecific hybridization in plant breeding.

...........................................................................................................................

........................................................................................................................... (1)

(ii) Outline one example of polyploidy.

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

...........................................................................................................................

........................................................................................................................... (2)

(Total 4 marks)

68. Polygalacturonase (PG) plays an important role in fruit softening by making the pectin of the

cell wall more soluble. It is synthesized only when the fruit is ripe.

In order to slow down the ripening of tomatoes (Lycopersicon esculentum), antisense RNA

technology was used. Messenger RNA from untransformed and transformed fruit was

hybridized to a radioactively labelled probe specific to the PG sense strand.

The results of a gel electrophoresis of mRNA are given below. (The size of the mRNA strands

is expressed in kilobases, kb.) The histogram shows these results expressed as the percentage of

PG mRNA in ripe untransformed fruit.

58

Lane 1: Ripe untransformed fruit

Lane 2: Unripe untransformed fruit

Lane 3: Ripe transformed fruit

Lane 4: Unripe transformed fruit

Lane

Lane

1 2 3 4

1 2 3 4

1.77

0.28

Siz

e /

kb

100

90

80

70

60

50

40

30

20

10

0%

PG

mR

NA

rel

ativ

e to

ripe

un

tran

sfo

rmed

fru

it

[Source: Smith et al., Nature, (1988), 334, pages 724–726]

(a) State the percentage of PG mRNA in ripe transformed fruit.

..................................................................................................................................... (1)

(b) Compare the results obtained for ripe and unripe fruit.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

59

(c) Using the information provided, explain how the antisense technology affects

transformed fruit.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

(Total 6 marks)

69. Light, water and carbon dioxide concentration all affect the productivity of crop plants.

(a) State two other factors that affect plant productivity.

1. .................................................................................................................................

2. ................................................................................................................................. (2)

(b) Explain how plant productivity can be increased by growing crops in greenhouses.

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (3)

(Total 5 marks)