Ilford County High School
Q1.(a)
When a seed starts to grow, the young root grows downwards towards gravity.
The young shoot grows upwards, away from gravity.
(i)
Name this type of plant response to gravity.
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(1)
(ii)
Give two reasons why it is useful for a young root to grow towards gravity.
1 ............................................................................................................
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2 ............................................................................................................
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(2)
(iii)
The root grows towards gravity due to the unequal distribution of a substance in
the root.
Draw a ring around the correct answer to complete the sentence.
auxin.
This substance is
chlorophyll.
sugar.
(1)
(b)
The drawings show some apparatus and materials.
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Ilford County High School
In this question you will be assessed on using good English, organising information
clearly and using specialist terms where appropriate.
Describe how the students could use some or all of the apparatus and materials
shown in the drawings to investigate the growth response of maize seedlings to light
shining from one side.
You should include a description of the results you would expect.
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Ilford County High School
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(6)
(Total 10 marks)
Q2.Plant hormones are used in horticulture.
(a)
Name one plant hormone.
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(1)
(b)
The diagram shows how new plants are produced using tissue culture.
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Ilford County High School
(i)
Tissue culture is a type of asexual reproduction .
Give the main features of asexual reproduction .
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(3)
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Ilford County High School
(ii)
Another method of producing new plants is by taking cuttings.
Suggest one advantage of using tissue culture and not using cuttings to
produce plants.
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(1)
(Total 5 marks)
Q3.
A student investigated growth responses in plants.
The student grew a bean seed in a box filled with moist soil, as shown in Diagram A. After
the seed had started to grow, the box was turned onto its side and placed in a dark room, as
shown in Diagram B.
(a)
Complete Diagram C to show what the root and shoot will look like three days later.
(2)
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Ilford County High School
(b)
Draw a ring around the correct answer to complete the sentence.
light.
The results of the investigation show that the root is sensitive to
moisture.
gravity.
(1)
(c)
A hormone in the plant causes the growth responses.
What is the name of this hormone?
Tick (
) one box.
Auxin
Statin
Steroid
(1)
(d)
Gardeners can use some plant hormones as weed killers.
(i)
Give one different use of plant hormones by gardeners.
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(1)
(ii)
Selective weed killers only kill some plants in a garden.
Killing weeds in a garden reduces competition between plants.
Give three factors that plants compete for.
1 ............................................................................................................
2 ............................................................................................................
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Ilford County High School
3 ............................................................................................................
(3)
(Total 8 marks)
Q4.
Charles Darwin investigated tropisms in plants.
Some students did an investigation similar to Darwin’s investigation.
The students:
• grew seeds until short shoots had grown
• used black plastic to cover parts of some of the shoots
• put the shoots in light coming from one direction
• put boxes over the shoots to keep out other light.
The diagrams show how the investigation was set up.
Two days later the students took off the black plastic covers and looked at the shoots.
The diagrams show the results.
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Ilford County High School
(a)
Give two variables that the students should control in this investigation.
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(2)
(b)
Shoot A bent towards the light as it grew.
Explain how.
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(4)
(c)
What conclusions can be drawn from the results about:
(i)
the detection of the light stimulus
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(1)
(ii)
where in the shoot the response to the light takes place.
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(1)
(Total 8 marks)
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Ilford County High School
Q5.
A student grew a plant in an upright pot.
She then put the pot in a horizontal position and left the plant in the dark for two days.
Diagram 3 shows the potted plant after two days in the dark.
Plant growing
upright
Plant put horizontal
in the dark
Plant after 2 days
in the dark
Explain fully why the plant responded in this way.
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(Total 4 marks)
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Ilford County High School
Q6.
Hormones control growth in plants.
(a)
Give two uses of plant growth hormones in horticulture.
1. ....................................................................................................................
2. ....................................................................................................................
(2)
(b)
A student grew a plant in an upright pot.
Later she put the pot in a horizontal position and left the plant in the dark for two days.
Diagram 3 shows the potted plant after two days in the dark.
Explain fully why the plant responded in this way.
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(4)
(Total 6 marks)
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Ilford County High School
Q7.
Plant plankton are aquatic microscopic organisms that photosynthesise. The graph
shows the numbers of plant plankton in the North Sea at different times of the year.
Use the data and your knowledge of photosynthesis and growth to explain:
(a)
why numbers of plant plankton were low in winter but increased rapidly during the
spring,
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(3)
(b)
the reduction in numbers of plant plankton in the early summer.
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(1)
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Ilford County High School
(Total 4 marks)
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Ilford County High School
M1.(a)
(i)
gravitropism / geotropism
not ‘…trophism’
ignore ‘positive’ or ‘negative’
1
(ii)
any two from:
•
•
•
anchorage
takes in water
takes in ions / minerals / salts / correct named example
allow nutrients
do not accept food
2
(iii)
auxin
1
(b)
Marks awarded for this answer will be determined by the Quality of
Communication (QC) as well as the standard of the scientific response.
Examiners should also refer to the information on page 5, and apply a best-fit
approach to the marking.
0 marks
No relevant content.
Level 1 (1 – 2 marks)
There is a basic description of a simple method involving seedlings and light.
Level 2 (3 – 4 marks)
There is a description of a method involving seedlings in 1-sided light, and a
control, with a correct observation.
Level 3 (5 – 6 marks)
There is a description of a method involving groups of seedlings in 1-sided light,
and in control conditions. It includes some correct measurements or
observations.
examples of Biology points made in the response:
•
•
•
•
•
•
•
use of scissors to cut tips from some shoots / cut hole in box
use of forceps for handling seedlings
use of ruler to measure lengths of shoots at start and at end
other factors controlled – eg temperature / water
use of lamp + box re. one-sided lighting
repetitions – each treatment ≥ 3 times
control in total darkness / all-round light
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Ilford County High School
•
•
time taken = several hours to a few days
sample results: tip exposed to 1-sided light→bend to light, tip
removed→vertical, control→vertical
6
[10]
M2.(a)
auxin
accept other named plant hormones
1
(b)
(i)
any three from:
•
no (fusion of) gametes / fertilisation
allow no meiosis or new cells only produced by mitosis
•
only one parent
allow not two parents
•
no mixing of genetic material
•
no genetic variation or genetically identical offspring
allow clones
3
(ii)
more / many offspring / plants (produced from one parent plant)
allow less damage to parent plant
ignore speed / cost
1
[5]
M3.
(a)
diagram to show root growing down
allow single lines or not attached or open ends for both marks
all branches must go down
1
diagram to show shoot growing up
all branches must go up
1
(b)
gravity
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Ilford County High School
1
(c)
Auxin
1
(d)
(i)
rooting / cuttings
accept other suggestions, eg fruit set / ripening
do not accept weed killers
1
(ii)
any three from:
•
light
ignore sun / energy
•
water / moisture
•
nutrients / ions / minerals
accept one named mineral
ignore nutrition / food
•
space / area
ignore soil / land / territory / volume
ignore reference to gases
3
[8]
M4.
(a)
any two control variables for 1 mark each:
•
age / size of shoots
•
species or type of plant / seeds
•
light intensity
accept amount of light / colour of light
•
(other) named condition eg temperature / water
2
(b)
ignore reference to phototropism
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ref to auxin / hormone
1
unequal (lateral) distribution
1
more hormone on dark side
1
causes growth on dark side
1
(c)
(i)
(detection) in tip / top / end
1
(ii)
(response) behind tip
allow at tip / end / top half
1
[8]
M5.
gravity
accept gravitropism / geotropism
1
caused redistribution of auxin / hormone to lower side of stem
1
these hormones stimulate growth of cells on the lower side of the stem only
1
so the stem grows upwards
1
[4]
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Ilford County High School
M6.
(a)
weedkillers
1
rooting (powders)
1
(b)
gravity
accept gravitropism / geotropism
1
caused redistribution of auxin / hormone to lower side of stem
1
these hormones stimulate growth of cells on the lower side of stem only
1
so the stem grows upwards
1
[6]
##
(a)
light and/or temperature too low in winter,
increasing light in spring leads to increase in photosynthesis
increasing temperature in spring leads to increasing metabolism/
growth/reproduction
for 1 mark each
3
(b)
they run out of minerals
for 1 mark
1
[4]
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Ilford County High School
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Ilford County High School
E2.(a)
A large proportion of students were able to correctly identify ‘auxin’. Examiners did not report
any other plant hormones being given, although a number of mammalian hormones were
suggested.
(b)
E3.
(i)
Some students had revised this part of the specification well and gave all four
marking points thus gaining the three marks. The last point on the mark scheme
was the most commonly attempted, although many fell short because they
simply stated ‘no variation in offspring’, rather than no genetic variation or
‘identical offspring’, rather than genetically identical offspring; ‘produces clones’
was an easier way of gaining this mark and was seen in a relatively high
proportion of responses. It was clear that some students had failed to recognise
the number of lines available and the ‘3 mark’ tariff as an indication of the extent
and detail required in the answer, offering just one or two ideas.
(ii)
It was surprising how many students were unaware that cuttings, like tissue
culture, produce genetically identical offspring. It was hoped that students would
use the diagram to infer (if they did not already know) that tissue culture is able
to produce many more offspring per parent plant than taking cuttings. There
were several further misconceptions, such as that ‘taking a cutting would kill the
plant’ or that using tissue culture would ‘cause no damage’, despite the diagram
showing the removal of a leaf. Many thought it an advantage that ‘only tissue
culture could be done all the year round’, that ‘tissue culture is more successful’,
that ‘tissue culture is cheaper / quicker’ or that ‘tissue culture takes up less
space’.
(a)
A significant minority of students did not attempt to complete the diagram. Of
those who did, a number simply extended the root and shoot horizontally. Credit was
given for correctly growing roots and shoots, even if they were poorly drawn and not
representative of either roots or shoots. If several roots were drawn, all of them had to
grow downwards to gain credit. A number of students drew an extra structure
emerging from the seed, for which no credit could be given since examiners did not
know if this was intended to be a root or a shoot. It is important that students read all
the information and instructions on the paper; examiners find it difficult to believe that
such a high proportion of students did not know what to do in this question, but rather
that they simply skipped over the information to ‘get at’ the more obvious questions.
(b)
Many students knew that roots are sensitive to gravity, though more than half thought
that the response was due to light. Once more students showed either a mistaken
understanding of the term ‘dark’ or simply missed the information in the question
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Ilford County High School
stem.
(c)
Many students correctly named the hormone as ‘auxin’, although ‘statin’ was an
attractive distractor for many.
(d)
(i)
Despite being told to give a use other than as a weed killer, a considerable
number of students suggested this very role, or the same as a description such
as ‘hormones kill some plants but not others’. In addition there were frequent
vague references to ‘increasing growth’ of plants along with answers about
‘fertilisers’, ‘statins’ and apparent insecticidal properties of plant hormones.
Furthermore unqualified references to cloning did not gain this mark as
examiners were looking for just a little more detail in terms of use in promoting
rooting. Consequently very few students scored the mark here and a significant
minority could offer no suggestions.
(ii)
Most students gained at least two of the three marks, with responses including
‘light’ and ‘water’. ‘Space’ was also not uncommonly seen by examiners,
although weaker answers along these lines, such as ‘land’, ‘soil’ and ‘territory’
were insufficient to gain credit. A few students gave ‘food’ or ‘nutrition’ and these
were not considered adequate replacements for ‘nutrients’, ‘minerals’ or ‘ions’.
E4.
(a)
Students were asked to name two variables that should be controlled during an
investigation into tropisms in plants. Several different choices were possible and
many students gained both available marks. The most common correct responses
referred to light intensity, species or type of plant and volume of water provided.
References to the ‘amount of light / water’ were accepted as equivalent to light
intensity and volume of water, respectively, however students should always be
encouraged to use appropriate scientific vocabulary whenever possible. Other
creditworthy answers that were seen included age or size of shoots, temperature and
soil type. Suggestions such as ‘time’, ‘direction of light’, ‘type of box’ and ‘black plastic
used’ gained no marks. Students should always be as specific as possible in answers
– responses such as ‘type of conditions’ and ‘surroundings they are grown in’ were
clearly weak and gained no credit.
(b)
Many answers to this part were excellent and displayed a sound understanding of
tropisms. Explanations such as ‘more auxin is found on the dark side and this causes
the cells here to grow’ were succinct and accurate, gaining all four marks in one
sentence. Despite this students often then felt the need to elaborate or repeat in order
to fill the space provided. Some students, however, were a little less certain of their
ground. ‘Hormone’ was an acceptable alternative for ‘auxin’ but a variety of other,
incorrect terms were used as well, including ‘enzyme’, ‘oestrogen’, ‘aphid’, ‘atom’,
‘axon’ and ‘toxin’. Many picked up the idea of unequal distribution of the hormone but
then gave the wrong side or described it as ‘going down to the root’, often ‘sinking due
to gravity’. Some hedged their bets and just said it was found on ‘one side’. When
writing about the effect of the hormone, students gained credit for terms which clearly
implied ‘growth’ such as elongation or cell division but not for weaker references like
‘bending’ (which was in the question stem), ‘leaning’, ‘tilting’ or ‘stretching’. Some
students had clearly revised tropisms in terms of geotropisms of shoots placed
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Ilford County High School
horizontally. These students often discussed ‘auxin concentration increasing on the
lower side’ or the effects of gravity on the movement of auxin, thus failing to apply their
knowledge to the particular situation presented in the question. Students were asked
to ‘explain how’ not to ‘explain why’ the plant responded in this way. Weaker students
continue to misinterpret questions and, consequently, fail to gain credit. Quite a few,
therefore, answered in terms of the shoot bending towards light ‘for more
photosynthesis’ and failed to address how this had happened.
(c)
E7.
(i)
Students were asked to draw conclusions from the results about the detection
of the light stimulus. Quite a few, however, answered only in terms of the
response by the shoot while some discussed the advantages of this response to
the plant. A number of students also appeared to have misread “detection” and
described the ‘direction’ of the light stimulus. Credit was given to any reference
to the tip or top of the shoot detecting the light but not to ‘the part where the
response occurs’ or ‘the side facing the light’.
(ii)
Students were directed to identify a ‘part of the shoot’. Most did this and there
were many correct answers. However, it was clear that having decided that ‘the
tip’ was their answer here, many students went back to part (c)(i) and crossed
out the correct answer, presumably thinking that the two could not be the same.
The mark scheme to this question was quite generous, allowing virtually any
reference to a region in the upper half of the shoot and many gained the mark
here as a result. Incorrect ideas ranged through all other parts of a plant - even
seed, stigma and stomata. Some students, again, misread the question - in this
case the key word ‘where’ - and answered in terms of ‘when’ or ‘how’ instead.
Most candidates correctly sorted out the climatic factors but significant numbers failed
to mention the effect of these on the rate of photosynthesis.
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