R2101 PLANT CLASSIFICATION, STRUCTURE & FUNCTION

Transcription

1 Including Examiners comments R0 PLANT CLASSIFICATION, STRUCTURE & FUNCTION Level Monday 6 February 07 09:30 0:50 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) iii) iv) ALL questions should be attempted; EACH question carries 0 marks; 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) vii) viii) Use black or blue ink only. Pencil can be used for drawing purposes only; Where plant names are required, they should include genus, species and where appropriate, cultivar; 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/505/967 Please turn over/..

2 Q Complete the table below: ANSWER ALL QUESTIONS i) name the FIVE stages in the plant life cycle; ii) state ONE distinct characteristic for EACH stage.. Stage in plant life cycle Characteristic of plant life cycle stage Total Mark Please see over/..

3 Q a) State THREE distinct functions of plant stems. Label the features indicated on the diagram below. External features of a woody stem 3 6 c) Name the type of leaf arrangement shown on the diagram in. Total Mark Please turn over/.. 3

4 Q3 a) Describe aerobic and anaerobic respiration by completing the table below. Aerobic respiration Anaerobic respiration Starting materials 3 Amount of energy produced Products 4 Name ONE horticultural situation where anaerobic respiration occurs. Total Mark Please see over/.. 4

5 Q4 a) Name TWO distinct functions of roots Draw a fully labelled (cross section) diagram of the internal structure of a young dicotyledonous root, to show EIGHT distinct features. 8 Total Mark Please turn over/.. 5

6 Q5 a) Describe FOUR ways in which growers can optimise the conditions for photosynthesis. 8 Name the products of photosynthesis. Total Mark Please see over/.. 6

7 Q6 a) Name the plant group to which monocotyledonous and dicotyledonous plants belong..... Describe FOUR distinct differences between the leaves of monocotyledonous and dicotyledonous plants. 8 c) Difference... Difference... Difference 3... Difference 4... Name ONE monocotyledonous plant. Total Mark Please turn over/.. 7

8 Q7 a) Describe the dispersal method for the THREE fruits shown, giving a NAMED plant example for EACH. X Description of dispersal method... Plant example... Y Description of dispersal method... Plant example... Question 7 continues on the next page. Please see over/ 8

9 Q7 Z Description of dispersal method... Plant example... State ONE function of fruits other than seed dispersal. Total Mark Please turn over/.. 9

10 Q8 a) c) State what is meant by the term transpiration. Name THREE environmental factors that affect the rate of transpiration. Describe THREE ways in which leaves minimise transpiration. 3 6 Total Mark Please see over/.. 0

11 Q9 a) Label EACH of the following flower parts onto the diagram below: i) tepal; ii) anther; iii) style; iv) receptacle; v) ovule. Longitudinal section of a monocotyledonous flower State ONE function for EACH of the flower parts listed in a). 5 Total Mark Please turn over/..

12 Q0a) Name the part of the embryo from which the root develops Describe ONE root adaptation for the functions listed, giving a NAMED plant example for EACH, by completing the table below. Function of root adaptation Climbing Plant example Description of root adaptation 3 Support 3 Perennation 3 Total Mark *******

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16 These questions are the property of the Royal Horticultural Society. They must not be reproduced or sold. The Royal Horticultural Society, Wisley, Woking, Surrey GU3 6QB. Charity Registration Number: 879/SC0386 6

17 R0 PLANT CLASSIFICATION, STRUCTURE & FUNCTION Level Monday 6 February 07 Candidates Registered 9 Total Candidates Passed % Candidates Entered % Passed with Commendation % Candidates Absent/Withdrawn % Passed % Candidates Deferred.95% Failed 04.0% Senior Examiner s Comments: 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. 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. 7

18 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. 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. 8

19 Q Complete the table below: i) name the FIVE stages in the plant life cycle; ii) state ONE distinct characteristic for EACH stage Stage in plant life cycle Characteristic of plant life cycle stage Q) Most candidates were able to name the stages of the plant life cycle in the correct order, i.e. seed, juvenile, adult/mature, senescence and death, and gained full marks. Germination and seedling growth are not stages in the plant life cycle but are part of the juvenile stage and could not be awarded any marks. The best candidates stated a range of characteristics for each stage of the life cycle and were awarded full marks. These included: Seed the plant is dormant and has a low rate of respiration, the embryo is enclosed in a testa and has a food store in the cotyledons or the endosperm Juvenile non- sexual, non-flowering and produces vegetative growth Adult/Mature sexual reproduction occurs involving flower, fruit and seed production Senescence flowering and fruiting cease, leaves show autumn colour and the stage of fruit after ripening Death cessation of metabolic processes including photosynthesis and respiration, cell death 9

20 Q a) State THREE distinct functions of plant stems. Label the features indicated on the diagram below. External features of a woody stem 3 6 c) Name the type of leaf arrangement shown on the diagram in. Qa) A range of functions of plant stems were stated by candidates who were awarded full marks. Acceptable answers included: Stems hold leaves in the best position for photosynthesis Stems hold flowers in the best position for pollination and fruit dispersal Stems store starch Stems transport water, sugar and minerals Young stems may also photosynthesise if green Functions of stem modifications were also acceptable and gained marks if qualified, e.g. storage of starch for perennation in stem tubers or rhizomes. Q Full marks were awarded to candidates who correctly labelled the diagram showing the external features of a woody stem. These were; apical/terminal bud, axillary/lateral bud, internode, node/leaf scar, girdle scar/apical bud scar/bud-scale scar, lenticel. Qc) Many candidates correctly named the leaf arrangement shown on the diagram from the position of the leaf scars as opposite and gained full marks. Candidates who described leaf shapes or structure could not be awarded any marks as these cannot be determined from a bare stem. 0

21 Q3 a) Describe aerobic and anaerobic respiration by completing the table below. Aerobic respiration Anaerobic respiration Starting materials Amount of energy produced Products 3 4 Name ONE horticultural situation where anaerobic respiration occurs. Q3a) The best candidates described aerobic and anaerobic respiration succinctly and gained maximum marks. Suitable answers were: Starting Materials in aerobic respiration are oxygen and glucose/sugar/carbohydrate whereas in anaerobic respiration only glucose/sugar/carbohydrate is used. Amount of Energy Produced; in aerobic respiration a large amount of energy is produced and a small amount is produced in anaerobic respiration. The amount of ATP produced by each process was also accepted. Products; in aerobic respiration these are water and carbon dioxide whilst in anaerobic respiration the products are ethanol and carbon dioxide. Although energy is also a product this was not awarded any marks as it was described in another section of the table. Q3 Candidates who correctly named waterlogged soils, compacted soils, inside large fruits and in stored or dormant seeds, as suitable horticultural situations where anaerobic respiration takes place, were awarded full marks. Candidates who named hydroponic growing systems could not be awarded any marks as these have oxygen in the water.

22 Q4 a) Name TWO distinct functions of roots. Draw a fully labelled (cross section) diagram of the internal structure of a young dicotyledonous root, to show EIGHT distinct features. 8 Q4a) The majority of candidates were able to name two functions of roots; e.g. anchorage/stability, uptake of minerals or water and storage of starch/carbohydrate/sugar for perennation, and gained full marks. Q4 Some candidates misinterpreted a cross section diagram which normally refers to a transverse section as a longitudinal section diagram which was accepted. Candidates who drew cross section diagrams and labelled eight features on them including; root hairs, cortex, epidermis, endodermis, pericycle, xylem, phloem, vascular cambium, stele/vascular bundle were awarded maximum marks. Candidates who drew longitudinal diagrams were also awarded marks for labelling the root cap, apical meristem and zones of cell division, elongation and maturation/differentiation. The stele should include the vascular tissues and pericycle only. Candidates could not be awarded any marks for drawings of a monocotyledonous root or a stem section.

23 Q5 a) Describe FOUR ways in which growers can optimise the conditions for photosynthesis. 8 Name the products of photosynthesis. Q5a) Candidates who gained full marks identified the factors which affect photosynthesis and then described ways of optimising them and/or explained their effect. A glasshouse situation was the most appropriate. Suitable descriptions included: Carbon dioxide used in photosynthesis must be replenished by the use of ventilation or increased by the use of gas or paraffin heaters or by using the exhaust from heating. Temperature which is optimal for enzymes involved in photosynthesis can be provided either by heating using hot water pipes or by cooling by the use of shading. Light intensity and duration can be increased and the correct wavelengths ( nanometers) for photosynthesis can be supplied through the use of suitable lamps e.g. high pressure sodium and mercury vapour. Plants can be supplied with specific nutrients which are needed for photosynthesis e.g. nitrogen, magnesium and iron. These are constituents of chlorophyll and if they are in short supply chlorophyll production is reduced. Water is required in sufficient quantities to prevent wilting or stomatal closure. It was not necessary for candidates to state the Law of Limiting Factors in this section of the question. Q5 Full marks were awarded to candidates who correctly named the products of photosynthesis as; oxygen and glucose. 3

24 Q6 a) Name the plant group to which monocotyledonous and dicotyledonous plants belong. Describe FOUR distinct differences between the leaves of monocotyledonous and dicotyledonous plants. 8 c) Name ONE monocotyledonous plant. Q6a) Most candidates correctly named angiosperms or flowering plants as the plant group to which monocotyledonous and dicotyledonous plants belong. Q6 Full marks were awarded to candidates who compared a specific difference between dicotyledonous and monocotyledonous leaves e.g. shape, margin, stomatal distribution etc. Suitable answers included: Monocotyledonous plants have strap shaped/lance shaped/narrow leaves whereas dicotyledonous plants have a diverse range of leaf shapes e.g. pinnate Monocotyledonous leaves have parallel venation whereas dicotyledonous leaves have a range of venations e.g. reticulate Monocotyledonous leaves have an undifferentiated mesophyll whereas dicotyledonous leaves have a palisade and spongy mesophyll Monocotyledonous leaves have stomata which is evenly distributed in their upper and lower epidermis whereas dicotyledonous leaves have more stomata in their lower epidermis Monocotyledonous leaves do not have a petiole whereas dicotyledonous leaves do Not all monocotyledonous leaves grow from the base of the plant and some have a midrib which was incorrectly described by a few candidates. These candidates could not be awarded any marks for their descriptions. Q6c) The majority of candidates were able to name one monocotyledonous plant and gained full marks. Acceptable answers included: Musa basjoo, Stipa gigantea and Narcissus Tête-à-tête. 4

25 Q7 a) Describe the dispersal method for the THREE fruits shown, giving a NAMED plant example for EACH. X Y Z State ONE function of fruits other than seed dispersal. Q7a) Candidates who correctly identified and described the method of dispersal for each of the fruits were awarded full marks. These were: X is Rubus fruticosus which uses internal animal dispersal where the fruit is ingested and excreted away from the parent plant Y is an Arctium lappa burr which is dispersed by attaching to animals fur, carried and rubbed off elsewhere Z is Taraxacum officinale which has a parachute mechanism for dispersal by wind using its umbrella-like pappas Other plant examples were accepted when described by candidates if the method of dispersal was the same as the one in the picture. Candidates who named and described Dipsacus fullonum (Teazel) and Cirsium arvense (Creeping Thistle) could not be awarded any marks as these are dispersed by wind and not animal attachment. Q7 Full marks were gained by candidates who correctly stated a function of fruits (other than seed dispersal). The best answers included; providing nutrients to the germinating seed, protection from herbivory and the control of germination/dormancy. Supplying food to animals or humans and adding organic matter to the soil could not be credited with any marks as they are not functions of fruits. 5

26 Q8 a) c) State what is meant by the term transpiration. Name THREE environmental factors that affect the rate of transpiration. Describe THREE ways in which leaves minimise transpiration. 3 6 Q8a) Most candidates stated that transpiration is the loss of water vapour or evaporation of water from the leaves and other plant surfaces and were awarded full marks. Candidates who stated that transpiration is the uptake of water by the roots or the flow of water through the plant in the transpiration stream could not be awarded any marks. Q8 The best candidates named the following as suitable environmental factors that affect the rate of transpiration and gained full marks. These were; light, temperature, humidity, wind speed and soil water availability. Q8c) Maximum marks were awarded to candidates who named three features of plants and described how these minimise transpiration. Suitable answers included: The cuticle is a waxy, waterproof barrier to water loss from the leaves The stomata can close in response to environmental conditions e.g. light and high temperature which prevents water vapour loss Stomata are concentrated on the underside of dicotyledonous leaves where humidity is highest and therefore reduces transpiration The ability of leaves to wilt reduces exposure to heating from the sun, increases humidity and reduces wind speed close to the leaf thus reducing transpiration Palisade mesophyll cells are tightly packed to prevent water escaping between cells 6

27 Q9 a) Label EACH of the following flower parts onto the diagram below: i) tepal; ii) anther; iii) style; iv) receptacle; v) ovule. Longitudinal section of a monocotyledonous flower State ONE function for EACH of the flower parts listed in a). 5 Q9a) The majority of candidates correctly identified and labelled the flower parts on the diagram and gained full marks. Q9 Candidates who showed a clear understanding and correctly stated a function for each of the flower parts were awarded full marks. Acceptable answers included: Tepals attract pollinators to the flower The anther encloses pollen grains containing the male gamete The style supports the stigma in the best position for pollen reception The receptacle is the point of attachment of the flower parts The ovule contains the female gamete or the embryo after fertilisation 7

28 Q0a) Name the part of the embryo from which the root develops. Describe ONE root adaptation for the functions listed, giving a NAMED plant example for EACH, by completing the table below. Function of root adaptation Climbing Plant example Description of root adaptation 3 Support 3 Perennation 3 Q0a) Candidates who named the radicle as the part of the embryo from which the root develops gained full marks. Q0 Full marks were awarded to candidates who described an appropriate example of a root adaptation for each function given. Suitable answers included: Climbing Hedera helix which has adventitious roots growing along the stem attaches itself to a support to enable the plant to reach better light for photosynthesis. Candidates who described tendrils or twining stems instead of roots could not be awarded any marks. Support Zea mays has roots which arise at the base of the stem which prevents the wind from blowing the plant over. Marks were also awarded for descriptions of buttress roots e.g. Ficus benjamina which are plank-like structures at the base of the stem providing support in shallow soils. Perennation Daucus carota which is a swollen tap root and Dahlia pinnata which is a root tuber, store starch over the winter which is used to support new growth in the spring. Candidates who drew diagrams which were correctly labelled were also awarded marks. ******* 8