Questions
Q1.
Plant growth substances
Photograph A shows the root of a plant when it was positioned horizontally.
The root was kept in the dark and left in this position.
Photograph B was taken three days later.
(a) (i) Complete the sentence by putting a cross (
) in the box next to your answer.
The process that resulted in the type of root growth shown in photograph B is
(1)
A
negative gravitropism
B
negative phototropism
C
positive gravitropism
D
positive phototropism
(ii) Explain how this change in root growth has occurred.
(3)
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(iii) Suggest the advantages to the plant of this response.
(2)
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(b) Rebecca and Andrew each set up an experiment to investigate the effect of light on plant shoots.
They also set up a control experiment.
Rebecca placed a black cap over the tip of her plant shoot.
Andrew removed the tip from his plant shoot, placed a thin block of jelly on top of the plant shoot and
then replaced the tip.
All three experiments were left for 24 hours.
(i) Suggest why Rebecca and Andrew set up a control experiment.
(1)
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(ii) Explain the results of Rebecca's experiment and Andrew's experiment.
(3)
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(Total for question = 10 marks)
Q2.
Auxins are plant hormones.
(a) (i) Complete the sentence by putting a cross (
) in the box next to your answer.
Auxins cause the shoot of a plant to grow towards light in a process called
(1)
A negative gravitropism
B negative phototropism
C positive gravitropism
D positive phototropism
(ii) Explain how auxins cause the shoot of a plant to grow towards light.
(2)
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Ethylene (ethene) is a plant hormone that stimulates the ripening of fruit.
The graph shows the effect of ethylene (ethene) concentration on the ripening of bananas after three
days.
(i) Describe the effect of ethylene (ethene) on the ripening of bananas.
(1)
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(ii) Explain which concentration of ethylene (ethene) a supermarket should use to be most cost effective
when ripening
bananas.
(2)
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*(c) Fruit ripening is one use of plant hormones.
Describe the other uses of plant hormones in crop production.
(6)
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(Total for Question is 12 marks)
Q3.
Faiza investigated the effect of rooting powder on plant cuttings.
She did not add rooting powder to one cutting.
She treated two more plant cuttings with different concentrations of rooting powder.
All three cuttings were then planted.
The diagrams show the cuttings after they had been growing for five weeks.
Faiza measured the length of four individual roots from each of the plants treated with rooting powder.
Her results are shown in the table.
percentage
root length / cm
rooting
1
2
3
4
Mean
powder (%)
2
0.9
1.4
1.0
1.1
5
2.3
2.5
1.3
3.1
2.3
(i) Calculate the mean root length for the 2% rooting powder.
(1)
answer = .............................................................................cm
(ii) Compare the mean root length in 2% with the mean root length in 5% rooting powder.
(1)
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Q4.
Plant hormones
(a) Faiza investigated the effect of rooting powder on plant cuttings.
She did not add rooting powder to one cutting.
She treated two more plant cuttings with different concentrations of rooting powder.
All three cuttings were then planted.
The diagrams show the cuttings after they had been growing for five weeks.
Describe the effect of rooting powder on the growth of these plant cuttings.
(2)
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(b) Faiza measured the length of four individual roots from each of the plants treated with rooting
powder.
Her results are shown in the table.
percentage
root length / cm
rooting
1
2
3
4
Mean
powder (%)
2
0.9
1.4
1.0
1.1
5
2.3
2.5
1.3
3.1
2.3
(i) Calculate the mean root length for the 2% rooting powder.
(1)
answer = .............................................................................cm
(ii) Compare the mean root length in 2% with the mean root length in 5% rooting powder.
(1)
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(c) (i) Complete the sentence by putting a cross (
) in the box next to your answer.
The response of roots to gravity is called
(1)
A gravitropism
B homeostasis
C photosynthesis
D phototropism
(ii) Explain how roots respond to gravity.
(2)
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(d) Rooting powder contains plant hormones.
Plant hormones are used extensively in the food production industry.
Describe some benefits of using plant hormones, other than rooting powder, in the food production
industry.
(3)
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Q5.
Auxins are plant hormones.
(i) Complete the sentence by putting a cross (
) in the box next to your answer.
Auxins cause the shoot of a plant to grow towards light in a process called
(1)
A negative gravitropism
B negative phototropism
C positive gravitropism
D positive phototropism
(ii) Explain how auxins cause the shoot of a plant to grow towards light.
(2)
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Q6.
Faiza investigated the effect of rooting powder on plant cuttings.
She did not add rooting powder to one cutting.
She treated two more plant cuttings with different concentrations of rooting powder.
All three cuttings were then planted.
The diagrams show the cuttings after they had been growing for five weeks.
Describe the effect of rooting powder on the growth of these plant cuttings.
(2)
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Mark Scheme
Q1.
Q2.
Answer
(a)(i)
(a)(ii)
(b)(i)
(b)(ii)
QWC
D
positive
phototropism
An explanation to
include the following
linked points
(auxins) move to the
shaded side of a
shoot (1) causing
cells on the shaded
side to elongate (1)
there is an increase
in the % of bananas
that ripen as the
ethylene
concentration
increases
An explanation to
include two of the
following points
• concentration of
ethylene to use is
3% (1)
• would be more
expensive to
increase the
ethylene
concentration above
3%
• when there is no
added ripening
benefits past 3%(1)
• below 3% not all
bananas are ripe (1)
*(c)
Acceptable
answers
Mark
(1)
accept move to the
side opposite the
light
accept get longer for
elongate Ignore
references to cell
division
Ignore positive effect
(2)
(1)
Do not credit ideas
related to longer
shelf life as the
question asks about
ripening
(2)
Indicative Content
Mark
A description to
include some of the
following points
• selective
weedkillers
• allows broadleaved plants to
grow uncontrollably
and die
• narrower-leaved
plants and crops left
unaffected
• auxins and or
gibberellins are used
• rooting powders
• plant cuttings are
dipped into rooting
(6)
Level
1
0
1-2
powder
• roots develop
rapidly
• large number of
plants can be
produced from the
same plant
• no need to wait
for plants to grow
from seeds
• auxins are used
• seedless fruit
production
• the fruit will
develop but the
seeds inside will not
• fruits are able to
grow larger (larger
biomass)
• gibberellins are
used
No rewardable content
• a limited description of at least one use
of plant hormones
• the answer communicates ideas using
simple language and uses limited scientific
terminology
• spelling, punctuation and grammar are
used with limited accuracy
2
3-4
• a simple description of two or more uses
of plant hormones
• the answer communicates ideas
showing some evidence of clarity and
organisation and uses scientific terminology
appropriately
• spelling, punctuation and grammar are
used with some accuracy
3
5-6
• a detailed description of two or more
uses of plant hormones with at least auxin,
gibberellins or other relevant hormone in the
correct context
• the answer communicates ideas clearly
and coherently uses a range of scientific
terminology accurately
• spelling, punctuation and grammar are
used with few errors
Total for question = 12 marks
Q3.
Question
Number
(i)
Answer
Acceptable answers
Mark
= 1.1(cm)
Question
Number
(ii)
Answer
Accept answer
written in table
Acceptable answers
(1)
Mark
the mean value for
5% rooting powder
shows a longer root
than the mean value
for 2% / ORA
Accept accurate
interpretation of data
(1)
Q4.
Question
Number
(a)
Question
Number
(b)(i)
Question
Number
(b)(ii)
Question
Number
(c)(i)
Question
Number
(c)(ii)
Question
Number
(d)
Answer
Acceptable answers
Mark
A description
including two of the
following points
• more / bigger /
longer roots are
grown in (2% / 5%)
powder compared to
no powder (1)
• bigger / taller
plants are grown in
(2% / 5%) powder
compared to no
powder (1) • more /
bigger leaves are
grown in (2% / 5%)
powder compared to
no powder (1)
Answer
Acceptable answers
(2)
Mark
Accept answer
written in table
Acceptable answers
(1)
Mark
= 1.1(cm)
Answer
the mean value for
5% rooting powder
shows a longer root
than the mean value
for 2% / ORA
Answer
A
Answer
Accept accurate
interpretation of data
Acceptable answers
(1)
Mark
Acceptable answers
(1)
Mark
An explanation
linking two of the
following points
• roots bend
towards gravity/roots
bend
downwards/grow
down (1) • auxin
distributed to lower
side/underside of
root (1) • auxin
inhibits growth
(causing this
downward bend) (1)
Answer
A description
including the
following points
(2)
Acceptable answers
Mark
(3)
• selective weed
killers result in higher
crop yield (1)
• seedless fruit are
more desirable to
consumers /
increase turnover (1)
• fruit ripening can
be controlled so less
wastage / link to
demand (1)
Answer
(i)
(ii)
Question
Number
Acceptable
answers
D
positive
phototropism
An explanation to
include the following
linked points
(auxins) move to the
shaded side of a
shoot (1) causing
cells on the shaded
side to elongate (1)
accept move to the
side opposite the
light
accept get longer for
elongate Ignore
references to cell
division
Answer
Acceptable answers
A description
including two of the
following points
• more / bigger /
longer roots are
grown in (2% / 5%)
powder compared to
no powder (1)
• bigger / taller
plants are grown in
(2% / 5%) powder
compared to no
powder (1) • more /
bigger leaves are
grown in (2% / 5%)
powder compared to
no powder (1)
Mark
(1)
(2)
Mark
(2)