Name:……………………………………….
Plant Biology Test Version 2 HL2 Biology
Total marks 45
1.
2.
3.
4.
5.
32K and 13U
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
Which would be an adaptation of xerophytes?
A.
Large air spaces
B.
Large numbers of stomata
C.
Hairs on the leaves
D.
Reduced roots
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
Fertilization, pollination and seed dispersal all occur during the reproduction of a flowering
plant. In what sequence do these processes occur?
A.
Seed dispersal
B.
Fertilization
C.
Pollination
D.
Seed dispersal
pollination
fertilization
pollination
seed dispersal
fertilization
seed dispersal
fertilization
pollination
What conditions will cause the highest rate of transpiration in a well-watered 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
1
6.
7.
8.
9.
In flowering plants, which of the following helps seed dispersal?
A.
Bees
B.
Pollen
C.
Mammals
D.
Germination
An organism has a waxy cuticle, reduced leaves, reduced number of stomata, and CAM
physiology. What type of organism could this be?
A.
A water lily plant found on the surface of an isolated pond
B.
A Paramecium, single celled swimming organism
C.
A single celled algal cell found at the water surface
D.
A desert based plant
What treatment is most likely to lead to germination?
A.
Soaking the seeds in water
B.
Increasing CO2 concentration
C.
Increasing light intensity
D.
Dehydrating the seeds
Outline the role of the phloem in the active translocation of sucrose.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(5K)
2
10.
Explain the role of auxin in phototropism.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(4K)
11.
Outline the procedure used in cloning plants by micropropagation.
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
(4K)
3
12.
Describe how flowering is controlled in long day plants (LDP)
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
(4K)
13.
Label the dicotyledonous seed below.
(4K)
4
14. 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
18
17
16
Height = 0.54 m
15
14
12
12
10
10
Number 8
of seeds 6
Number 8
of seeds 6
5
4
3
2
1
7
5
4
3
3
2
1
1
8.
9
11
12
.9
to
14
.9
15
to
17
18
.9
to
20
21 .9
to
24
ov
er
24
to
9
to
5.
9
Distance travelled / cm
6
to
to
3
0
2.
9
0
to
20 19
to
40 39
to
60 59
to
80 79
10 to 9
0
9
to
12 11
9
0
to
14 13
9
0
to
16 15
9
0
to
18 17
9
0
to
20
0
0
9
4
0
2
3
Height = 10.8 m
16
14
4
17
Distance travelled / m
[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: ...............................................................................................
(1U)
(b)
State the effect of height on seed dispersal.
.....................................................................................................................................
(1U)
(c)
Suggest two reasons for the effect of the drop height on the distance travelled by the
seeds.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2U)
5
The following graphs show the rate and timing of seed release from different species of grass in
the same area during the summer.
100
100
Festuca rubra
Holcus lanatus
Rate of
seed fall /
number 50
week –1
100 cm –2
Rate of
seed fall /
number 50
week –1
100 cm –2
0
0
14 21 28 5 12 19 26 2
June
July
16
30
14 21 28 5 12 19 26 2
August
June
July
16
30
August
400
Agrostis stolonifera
600
Poa trivialis
300
Rate of
seed fall / 400
number
week –1
100 cm –2 200
Rate of
seed fall /
number 200
week –1
100 cm –2 100
0
0
14 21 28 5 12 19 26 2
June
July
16
August
30
14 21 28 5 12 19 26 2
June
July
16
30
August
[Source: J L Harper, Population Biology of Plants, Academic Press (Harcourt Brace Jovanovich) 1997, page 57]
(d)
Identify the grass species which produces the most seeds in this area.
.....................................................................................................................................
(1U)
(e)
Identify the grass species which produces the most seeds in June.
.....................................................................................................................................
(1U)
(f)
Compare seed production for all species relative to the timing of their release.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3U)
6
(g)
Suggest two benefits for these plants in the timing of seed release.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2U)
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 and
carbohydrate content.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2U)
7
(i)
Sate which fruit would have the highest energy content.
.....................................................................................................................................
(1U)
(j)
Suggest one advantage and one disadvantage of dispersal of seeds by animals.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2U)
8
Mark scheme
13.
14.
15.
16.
C
C
A
C
17.
18.
19.
20.
B
C
D
A
21.
(phloem) composed of living tissue;
composed of companion cells / sieve tube members;
companion cells involved in ATP production;
Active transport of sucrose at the source/named source into sieve tube;
Role of proton gradient/co transporter protein in loading/transport of sucrose in sieve tube;
Water follows by osmosis creating high pressure;
Sucrose removed at sink/named sink;
Water leaves/low pressure at sink/named sink;
Pressure gradient/different hydrostatic pressures between source and sink from source to sink
Bi-directional transport;
[5]
22.
shoots of plants grow towards light / positively phototropic;
shoot tips produce auxin;
detection of light by phototropins;
production of auxin efflux proteins/PIN proteins;
distributed from the lighter to the darker/shaded side/greater conc on shaded side;
promotes secretion of hydrogen ions into cell walls which loosens connections/H bonds
between cellulose fibres;
water intake allows cell expansion (on shaded side);
4 max
23.
small piece of plant removed;
tissue is placed on sterile nutrient agar gel containing high auxin concentration; (idea of sterility
should be evident either in marking point 1 or 2)
callus growth / tissue cut into smaller pieces with same treatment/same type of nutrient agar gel
with high auxin;
callus growth / tissue is transferred to agar gel containing high cytokinin;
gibberellin is sometimes added;
plantlets are separated and transferred to soil;
24.
phytochrome system / biological clock located in leaf;
LDP needs a day length longer than a critical period / night length shorter than a critical period;
idea of critical period is important
Pr converted to Pfr during daylight;
Pfr remains at the end of short nights;
Pfr stimulates flowering;
flowering hormone / Flowering time protein/ florigen released;
example of LDP (spinach, radish, lettuce, irises);
[4]
[4]
25.
Award [1] for each of the following structures labelled.
Testa/seed coat:
Radicle:
Plumule:
Cotyledon(s)
[4]
26.
(a)
height 0.54 m: 60–79 cm / 0.60–0.79 m (from the plant)
9
and height 10.8 m: 0–2.9 m
(from the plant);
Units needed for both parts of the answer.
(b)
(c)
1
the greater the height from which the seed fell,
the further it travelled from the parent plant
1
at the greater height:
seed can catch the wind to travel further / updrafts / more wind at greater height;
farther to the ground and does not travel straight down / more time to be blown before
hitting the ground;
at lower height:
seed can fall straight down;
seed can hit downdraft and fall faster;
Any point must explain the difference in distance
travelled from the two heights.
2 max
(d)
Agrostis stolonifera
1
(e)
Poa trivialis
1
(f)
Poa produces seed earliest in the summer / June;
Holcus produces most seed in July;
Agrostis and Festuca produce seed in (late July to) August;
Holcus and Poa have a peak time of seed fall / short period of seed fall;
Agrostis and Festuca may continue to increase seed production to September;
Accept any of these points made conversely as an alternative.
3
(g)
Award [1] each for any two of the following.
to avoid predation / disperse at times when other species are dispersing their seeds;
to avoid competition;
late in the year to allow seeds to germinate over winter / better germination conditions;
better dispersal conditions / more wind / animals for dispersal;
photoperiod – required day length for flowering;
more energy stored at the end of the summer for seed production;
more light / warmth / better conditions for seedling photosynthesis /
growth;
2 max
(h)
tropical fruits have higher lipid content than temperate fruits;
temperate fruits have greater carbohydrate content than tropical fruits
(i)
mistletoe;
(j)
Award [1] for advantage and [1] for disadvantage.
2 max
1
animal dispersal advantage:
travel further / digestion cracks seed coat for better germination / deposited in feces with
organic matter / better in areas with little wind;
animal dispersal disadvantage:
predation / seeds eaten / deposited in poor environment / buried too deep / buried too
shallow (if deposited with feces) / animal might become extinct / scarce;
2 max
10