Download RHS Level 2 - Plant Classification, Structure and Function

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R2101
PLANT CLASSIFICATION, STRUCTURE & FUNCTION
Level 2
Monday 9 February 2015
09:30 – 10:50
Written Examination
Candidate Number: …………………………………………………………………
Candidate Name: ……………………………………………………………………
Centre Number/Name: ……………………………………………………………..
IMPORTANT – Please read carefully before commencing:
i)
The duration of this paper is 80 minutes;
ii)
ALL questions should be attempted;
iii)
EACH question carries 10 marks;
iv)
Write your answers legibly in the lined space provided. It is NOT
necessary that all lined space is used in answering the questions;
v)
Use METRIC measurements only;
vi)
Use black or blue ink only. Pencil can be used for drawing purposes only;
vii)
Where plant names are required, they should include genus, species and
where appropriate, cultivar;
viii)
Where a question requires a specific number of answers; only the first
answers given that meet the question requirement will be accepted,
regardless of the number of answers offered;
ix)
Please note, when the word ‘distinct’ is used within a question, it means
that the items have different characteristics or features.
Ofqual Unit Code K/505/2967
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ANSWER ALL QUESTIONS
MARKS
Q1
a)
Name ONE monocotyledonous and ONE dicotyledonous plant.
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monocotyledon…………………………………………………………………….
dicotyledon……………………………………………………………………..…..
b)
State ONE difference between monocotyledonous and dicotyledonous plants
for EACH plant organ by completing the table below.
Plant organ
Monocotyledon
Dicotyledon
Stem
2
Root
2
Flower
2
Leaf
2
Total Mark
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MARKS
Q2
a)
State TWO functions of flowers.
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b)
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Name EACH of the following features labelled on the diagram below.
A typical dicotyledonous flower
c)
Name the collective terms used for the following structures:
i)
ii)
all the petals;
all the sepals.
2
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Total Mark
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Q3
a)
State what is meant by the term ‘plant tissue’.
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b)
Describe THREE characteristics for TWO NAMED transport tissues by
completing the table below.
Name of transport tissue
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Characteristics
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1
2
3
2
1
2
3
Total Mark
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MARKS
Q4
a)
Name the site of aerobic respiration in the cell.
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b)
State the basic equation for aerobic respiration.
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c)
Describe the effects of water logged soils on plant roots.
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Q5
a)
State the difference between the juvenile and adult stages of the plant lifecycle.
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b)
Describe TWO horticultural situations where juvenile growth is an advantage.
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c)
Describe TWO horticultural situations where adult growth is an advantage.
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MARKS
Q6
a)
Label EACH of the following features on the diagram below:
i)
ii)
iii)
iv)
palisade mesophyll cell;
cuticle;
spongy mesophyll cell;
epidermal cell.
4
Internal structure of a typical dicotyledonous leaf
b)
State THREE ways by which the leaf structure shown in a), is designed to
maximise photosynthesis.
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7
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MARKS
Q7
a)
Identify the adaptations for climbing shown below, giving a NAMED plant
example for EACH.
2
Name of adaptation…………………. Plant example……………………………….
2
Name of adaptation…………………. Plant example……………………………….
2
Name of adaptation…………………. Plant example……………………………….
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b)
2
State TWO reasons why plant organs may be adapted for climbing.
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c)
Describe ONE other adaptation used by plants to climb.
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Q8
a)
Describe how water enters plant cells by osmosis.
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b)
State what is meant by the term ‘cell turgor’.
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c)
1
Name ONE other process by which water moves in the plant.
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Q9
a)
State TWO functions for EACH of the following seed parts by completing the
table below.
Seed part
radicle
Function
1.
2
2.
cotyledon
1.
2
2.
testa
1.
2
2.
b)
State the difference between epigeal and hypogeal germination, giving a
NAMED example of EACH.
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Q10
a)
List FOUR external features of a woody plant stem.
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b)
Describe ONE feature listed in a).
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c)
Identify TWO ways that leaves can be arranged on a stem by completing the
table below.
Name of
arrangement
4
Drawing of arrangement
Total Mark
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DO NOT USE THIS PAGE
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DO NOT USE THIS PAGE
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DO NOT USE THIS PAGE
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©These questions are the property of the Royal Horticultural Society.
They must not be reproduced or sold.
The Royal Horticultural Society, Wisley, Woking, Surrey GU23 6QB.
Charity Registration Number: 222879/SC038262
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R2101
PLANT CLASSIFICATION, STRUCTURE & FUNCTION
Level 2
Monday 9 February 2015
Candidates Registered
Candidates Entered
Candidates Absent/Withdrawn
Candidates Deferred
919
792
117
10
86.18%
12.73%
1.09%
Total Candidates Passed
Passed with Commendation
Passed
Failed
630
368
262
162
79.55%
46.47%
33.08%
20.45%
Senior Examiner’s Comments:
1
Candidates should be able to demonstrate a good range of plant knowledge and be
able to give accurately named plant examples where appropriate. Common names
and generic names are often too vague and cannot be rewarded in the positive
manner that genus, species and where appropriate, variety/cultivar can. This is
particularly important when answering questions relating to particular (named)
plant(s). Marks can only be awarded for these narratives where the example(s) are
correctly and fully identified.
2
Candidates must be able to display accurate knowledge of the technical terms and
concepts detailed in the syllabus, in the context of horticulture and also be aware that
wider interpretation will not be rewarded. The examination should be regarded as a
possible introduction to higher level studies, which will only be open to those who are
in possession of a clear understanding of the horticultural terms and concepts which
are current.
3
The introductory rubric given on the first page of each question paper should be read
carefully by candidates. At each examination there are a significant number of
candidates who ignore or misread the instructions given and consequently may not
perform as well as they could have done.
4
Candidates should pace themselves during each paper. The most successful
candidates allow sufficient time to read the question thoroughly before answering it
and also take time to read through their answers. They should take care to write as
legibly as possible, so that the examiner is in no doubt about what is intended.
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5
Candidates need to interpret key words within questions, particularly those such as
‘state’, ‘list’ and ‘describe’. Questions requiring descriptions or explanations obviously
require a more detailed answer than those requiring a list.
6
It is important to ensure that responses to questions are to the point. Candidates
should bear in mind that small sketches might be used to convey information more
succinctly than words.
7
Successful candidates ensure that their answers are focused and to the point. It is
disappointing when they cannot be rewarded for their efforts because the answer is
irrelevant to the particular question. Candidates should take note of the mark
allocation for specific sections and allocate their time and efforts accordingly.
8
Diagrams can enhance an answer and where appropriate can replace detailed
descriptions. They should be large, clear and well annotated, ensuring that labels are
properly attached to the features they describe. Diagrams should preferably be in
pencil. Colour may be used successfully but only where it is relevant to the answer.
9
In each examination it is clear that some candidates are ill prepared to answer
papers of the type set. It is essential that candidates have the opportunity to practice
questions. Ideally some papers should be answered in a time constrained situation.
Appropriate feedback must, in any case be provided.
18
Overall Examiners’ Comments:
MARKS
Q1
a)
Name ONE monocotyledonous and ONE dicotyledonous plant.
2
monocotyledon…………………………………………………………………….
dicotyledon……………………………………………………………………..…..
b)
State ONE difference between monocotyledonous and dicotyledonous plants
for EACH plant organ by completing the table below.
Plant organ
Monocotyledon
Dicotyledon
Stem
2
Root
2
Flower
2
Leaf
Q1a)
2
Most candidates were able to give the full botanical name of one monocotyledonous
plant e.g. Lolium perenne or Lilium candidum and one dicotyledonous plant e.g.
Quercus robur or Wisteria sinensis and were awarded full marks.
Candidates who incorrectly named conifers could not be awarded any marks.
Q1b) The best candidates described the difference in one feature only for each plant organ
rather than a list of features as only the first one could be credited i.e. leaf shape,
venation and structure are all distinct features of leaves and should be compared
separately.
Full marks could only be awarded if both parts of a paired comparison were given.
Diagrams were credited if they were clearly drawn and labelled.
Stems
Full marks were awarded to candidates who stated that monocotyledonous stems
are unbranched while dicotyledonous stems are branched. Other acceptable
answers included; monocotyledonous stems are herbaceous, without secondary
thickening or having a vascular cambium whereas dicotyledonous stems can be
either herbaceous or woody with secondary thickening and a vascular cambium and
the vascular bundles are scattered in monocotyledonous stems and arranged in a
ring in dicotyledonous stems.
19
Root
Candidates who stated that monocotyledonous plants have a fibrous/adventitious
root system whereas dicotyledonous plants can either have a tap or primary root
system with laterals or a fibrous/adventitious root system, gained full marks. Some
candidates correctly described monocotyledonous plants as having a central pith and
a stele with multiple arms compared to dicotyledonous roots that have a central
xylem and a stele with few arms. Full marks were also awarded to candidates who
stated the absence of vascular cambium and secondary thickening in
monocotyledonous roots compared to their presence in dicotyledonous roots.
Flower
The best candidates stated that monocotyledonous flowers have tepals compared to
dicotyledonous flowers which have both petals and sepals and were awarded full
marks. Other acceptable answers included; flower parts (not flowers themselves) are
in multiples of 3 in monocotyledonous plants and 4 or 5 in dicotyledonous plants.
Leaf
Full marks were awarded to candidates who stated that monocotyledonous leaves
are linear or strap-like, whereas dicotyledonous leaves have many different shapes.
Marks were also gained by candidates who stated that monocotyledonous leaves
have parallel venation while dicotyledonous leaves have branching veins in various
patterns, a lack of a petiole and simple margins in monocotyledonous leaves and a
petiole and different types of margin, e.g. toothed or lobed in dicotyledonous leaves.
Descriptions of seed leaves could not be accepted and did not gain any marks as
these are not true leaves.
20
MARKS
Q2
a)
State TWO functions of flowers.
2
b)
Name EACH of the following features labelled on the diagram below.
6
A typical dicotyledonous flower
c)
Name the collective terms used for the following structures:
i)
ii)
Q2a)
all the petals;
all the sepals.
2
The majority of candidates were able to correctly state two functions of flowers and
gained full marks. Suitable answers included; aiding pollination, producing fruits,
seeds, pollen or ovules and enabling sexual reproduction.
Q2b) Full marks were awarded to candidates who correctly identified the anther, filament,
stigma, style, ovary and receptacle.
Q2c)
Most candidates gained full marks by correctly naming;
i)
ii)
corolla (all the petals).
calyx (all the sepals).
21
MARKS
Q3
a)
State what is meant by the term ‘plant tissue’.
2
b)
Describe THREE characteristics for TWO NAMED transport tissues by
completing the table below.
8
Name of transport tissue
Characteristics
1
1
2
3
1
2
2
3
Q3a) Candidates who stated that the term plant tissue means a collection of cells working
together to perform a specific function were awarded full marks.
The best candidates were clear that the function related to the tissue and not the cell
and that tissues can contain more than one cell type.
Q3b) The transport tissues xylem and phloem were correctly named by most candidates who
were awarded full marks.
Candidates who named sclerenchyma and parenchyma could not be awarded any
marks as these as not transport tissues.
As the question asked for three characteristics; descriptions of the structure, function
and position of each tissue and its typical cells were accepted.
Suitable answers included; xylem tissue has tube-like, lignified, dead xylem vessels
and tracheids which allow transport of water and nutrients upwards from the roots.
Phloem tissue contains living sieve tube cells, without a nucleus, joined end to end by
sieve plates which transport sugars in both directions. They also have adjacent
companion cells which control their function.
Candidates who described the location of tissues needed to be precise e.g. phloem is
found in the outer part of the vascular bundle and xylem forms the inner part of the
vascular bundle in dicotyledonous stems.
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MARKS
Q4
a)
Name the site of aerobic respiration in the cell.
1
b)
State the basic equation for aerobic respiration.
3
c)
Describe the effects of water logged soils on plant roots.
6
Q4a)
The majority of candidates correctly named the site of aerobic respiration in the cell
as the mitochondrion and gained full marks.
Q4b) Most candidates were able to correctly state the equation for aerobic respiration as;
glucose (or carbohydrates/sugars/starch) + oxygen → carbon dioxide + water + energy/ATP
Chemical formula and word equations were both accepted and marks were awarded
for correct inputs/products as long as they were on the correct sides of the equation.
Some candidates confused aerobic respiration with photosynthesis and could not be
awarded any marks.
Q4c)
Candidates who recognised that the question was concerned with respiration and
described the effects of waterlogging on root cells as well as on the root as an organ
gained high marks. Marks were awarded for stating that soil pore spaces would be
filled with water, excluding oxygen and leading to a reduction in aerobic respiration
and a switch to anaerobic respiration. This is a less efficient process due to the
incomplete breakdown of glucose so less energy is released in the cell. Toxic ethanol
is produced leading to cell and root death.
Other effects in the root e.g. poor growth, increased susceptibility to disease and
subsequent rotting, together with reduced nutrient and water uptake due to lack of
energy were also awarded marks.
Candidates who described root adaptations to waterlogging e.g. pneumatophores
also gained marks.
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MARKS
Q5
a)
State the difference between the juvenile and adult stages of the plant lifecycle.
2
b)
Describe TWO horticultural situations where juvenile growth is an advantage.
4
c)
Describe TWO horticultural situations where adult growth is an advantage.
4
Q5a)
Candidates who were awarded full marks were able to make the clear distinction
between the juvenile stage being vegetative/non-flowering and the adult stage being
sexually reproductive/producing flowers and fruit.
The term ‘sexual reproduction’ should be used to make this clear as opposed to just
‘reproduction’, which could also refer to vegetative reproduction.
In sections b) and c) of this question, the best candidates fully understood the
distinction between the two life cycle stages in section a) of the question. These
candidates related their answers to non-flowering or flowering growth rather than
describing juvenile and adult growth in terms of the size or age of the plant. These
candidates also provided a relevant horticultural situation.
Q5b) The best candidates correctly described horticultural situations where juvenile growth
is an advantage and gained full marks. Suitable answers included;
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Q5c)
Stem cuttings taken from juvenile growth/plants root more easily.
Some hedges are pruned to encourage juvenile growth, which retains its leaves
in winter e.g. Fagus sylvatica.
Coppicing/pollarding/stooling produces juvenile leaf forms, which are attractive in
the border or may be used in floristry e.g. Eucalyptus gunnii.
Harvesting of leafy crops e.g. spinach or root crops e.g. carrot is done when the
plant is juvenile and before it becomes adult and flowers (bolts).
Lawns are mown to maintain juvenile growth, which is leafy rather than flowering.
The best candidates correctly described horticultural situations where juvenile growth
is an advantage and gained full marks. Suitable answers included;
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Crop production where fruit is required e.g. apples/orchards.
Flower, fruit and seed production for decoration in the garden or to attract wildlife
e.g. Pyracantha spp. for fruits or Dahlia spp. as a cut flower.
Propagation where seed is collected and sown.
Plant breeding involving cross pollination/hybridisation of flowers.
Grafting of adult scions for earlier flowering e.g. Wisteria spp.
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MARKS
Q6
a)
Label EACH of the following features on the diagram below:
i)
ii)
iii)
iv)
palisade mesophyll cell;
cuticle;
spongy mesophyll cell;
epidermal cell.
4
Internal structure of a typical dicotyledonous leaf
b)
State THREE ways by which the leaf structure shown in a), is designed to
maximise photosynthesis.
Q6a)
The majority of candidates correctly labelled all four parts of the leaf structure and
gained full marks.
Candidates who confused the cuticle and epidermal cell and the palisade and spongy
mesophyll cells could not be awarded any marks.
Q6b) Candidates who clearly linked the leaf structure shown in the diagram to maximising
photosynthesis were awarded full marks. These candidates identified the feature of
the leaf and described the way in which it optimised photosynthesis. Suitable
answers included;
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The cells in the palisade mesophyll layer are on the upper surface to intercept
maximum light. They are tightly packed and contain many chloroplasts.
The air spaces of the spongy mesophyll enable gas exchange.
The leaf itself is thin to maximise light interception and gas exchange.
The epidermis and cuticle are transparent to allow for light transmission.
Stomata are on the underside of the leaf to enable gas exchange.
Marks could only be awarded to candidates who mentioned the presence of stomata
and the waxy cuticle controlling water loss if this was related to photosynthesis e.g.
water loss causes wilting which reduces light interception or stomatal closure, which
reduces carbon dioxide uptake.
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6
MARKS
Q7
a)
Identify the adaptations for climbing shown below, giving a NAMED plant
example for EACH.
Name of adaptation…………………. Plant example……………………………….
2
Name of adaptation…………………. Plant example……………………………….
2
Name of adaptation…………………. Plant example……………………………….
2
b)
State TWO reasons why plant organs may be adapted for climbing.
2
c)
Describe ONE other adaptation used by plants to climb.
2
Q7a)
The illustrations showed in order, examples of; tendril, twining stem and tendril.
Candidates who gave suitable plant examples for each were awarded full marks e.g.
tendril – Pisum sativum, Vitis vinifera or Passiflora caerulea and twining stem –
Phaseolus coccineus or Wisteria sinensis.
Full botanical names for plants were required for candidates to be able to be
awarded marks as some genera have both climbing and non climbing species e.g.
Lonicera alone could not be awarded any marks but Lonicera periclymenum (twining
stem) could.
Q7b) The best candidates stated two full reasons why plant organs may be adapted for
climbing and gained full marks. Acceptable answers included;


To gain access to increased light for photosynthesis.
To raise the plant parts above other vegetation for better pollination, seed and
fruit dispersal or to avoid herbivory.
Candidates who stated supporting the plant or to avoid competition with other plants
as reasons why plant organs may be adapted for climbing could not be awarded any
marks unless further explanation was given.
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Q7c)
Candidates who named and described adaptations used by plants for climbing other
than those shown in part a) of the question were awarded full marks. Suitable
examples described included;
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Adventitious roots which grow along the stem and attach to walls and other
surfaces.
Prickles (e.g. Rosa spp.) which enable plants to hook onto and scramble over
other plants.
Adhesive pads at the end of tendrils which attach to a support.
Candidates who gave thorns and spines as examples could not be awarded any
marks as these are primarily for defensive adaptations and not climbing structures.
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MARKS
Q8
a)
Describe how water enters plant cells by osmosis.
5
b)
State what is meant by the term ‘cell turgor’.
4
c)
Name ONE other process by which water moves in the plant.
1
Q8a)
Candidates who described the movement of water into cells rather than the pathway
of water movement across the root or through the whole plant, (which was not asked
for) gained full marks. When describing the differences in solute/water concentration
governing the flow into the cell, candidates were required to make it clear which
(solute or water) they were describing. Stating that water moves from a high to a low
concentration could not be awarded any marks.
Most candidates understood that in osmosis, water passes through a semi/selectively
permeable membrane and that the cell membrane excludes solute but allows the
passage of water. Marks were also gained by describing the movement of water
through the permeable cell wall and the concept that water moves down a water
concentration gradient into the cell.
Candidates who described osmosis as an active process could not be awarded any
marks as this is not true.
Q8b) The best candidates linked cell turgor to the water content of cells and also stated the
role of the vacuole in storing water. These candidates also stated that water entering
the cells sets up an internal pressure outwards, against the rigid cell wall (turgor
pressure). Turgor does not support the cell contents as such, but the combined
turgor pressure of cells in herbaceous plants supports the plant body and helps to
keep it upright. Candidates also correctly stated that loss of turgor leads to wilting in
non-woody plants.
Q8c)
The majority of candidates were able to name one process by which water moves in
the plant and were awarded full marks. Suitable answers included; transpiration,
capillary rise, diffusion and mass flow.
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MARKS
Q9
a)
State TWO functions for EACH of the following seed parts by completing the
table below.
Seed part
Function
radicle
1.
cotyledon
2.
1.
testa
2.
1.
2
2
2
2.
b)
Q9a)
State the difference between epigeal and hypogeal germination, giving a
NAMED example of EACH.
Candidates who stated the function of the seed parts rather than the structure were
awarded full marks. Acceptable answers included;
Radicle
 Tissue which gives rise to the new embryonic root.
 For anchorage of the plant.
 Uptake of water or nutrients.
Cotyledon
 Storing starch/carbohydrate/sugars or energy.
 Protection of the plumule as it grows through the soil.
 Cotyledons photosynthesising or acting as the first leaves if above
ground/epigeal germination.
Testa
 Protection against pathogens or the environment.
 Dormancy due to the exclusion of water and air or the presence of
germination inhibitors.
 Holds seed contents together.
Q9b) Most candidates gained full marks by stating that; epigeal germination is when the
cotyledons emerge above the soil and remain below the soil in hypogeal germination.
Candidates also provided a suitable example of epigeal germination e.g. Phaseolus
vulgaris and hypogeal germination e.g. Vicia faba.
Diagrams were accepted if fully labelled. Candidates should be encouraged to use
plant examples which are easy to verify.
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4
MARKS
Q10
a)
List FOUR external features of a woody plant stem.
4
b)
Describe ONE feature listed in a).
2
c)
Identify TWO ways that leaves can be arranged on a stem by completing the
table below.
4
Name of
arrangement
Drawing of arrangement
Q10a) The majority of candidates were able to list four external features of a woody plant
stem and were awarded full marks. Suitable answers included; lenticel, bark/cork,
leaf/bud scar, girdle/bud scale/scale scar, node, internode, thorn. The word bud
needed to be qualified for full marks e.g. axillary/lateral bud, apical/terminal bud.
Candidates who listed internal features of a stem e.g. meristem or cork cambium
could not be awarded any marks.
Q10b) Candidates gained full marks for good descriptions of one of the features listed in
part a) of the question e.g.



A lenticel is a pore in the bark which enables gaseous exchange between inner
tissues and the outside.
Bark/cork is the outer layer which has waterproof cork cells. This protects the
stem from water loss, pathogens or damage.
Girdle scar is the position of last year’s apical bud showing the point of
attachment of the apical bud scales.
Q10c) Candidates who identified the following leaf arrangements gained full marks. Suitable
examples included; alternate, opposite, whorled and decussate.
Candidates who identified pinnate and palmate or simple and compound leaf
structures rather than leaf arrangements, could not be awarded any marks.
*******
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