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GCE JUN 2009 : (AS 2) Physiology and Ecology

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1 2 Centre Number 3 71 4 Candidate Number 5 6 ADVANCED subsiDiAry (As) General Certificate of Education 2009 7 8 9 biology 11 Assessment Unit AS 2 12 assessing 13 Module 2: Physiology and Ecology 14 [Asb21] 15 ASB21 10 FriDAy 12 JuNE, AFTErNOON 16 17 18 TiME 19 1 hour. 20 21 iNsTruCTiONs TO CANDiDATEs 22 Write your Centre Number and Candidate Number in the spaces provided at the top of this page. Write your answers in the spaces provided in this question paper. 24 Answer all eight questions. 23 Question Number 25 26 For Examiner s use only iNFOrMATiON FOr CANDiDATEs 27 The total mark for this paper is 55. Section A carries 43 marks. 28 Section B carries 12 marks. 29 You should spend approximately 15 minutes on Section B. You are expected to answer Section B in continuous prose. 30 Quality of written communication will be assessed in section b. 31 Figures in brackets printed down the right-hand side of pages indicate the marks awarded to each question or part question. 1 2 3 4 5 6 7 32 8 33 Total Marks 34 35 4680 Marks Section A Examiner Only Marks 1 Remark Describe the structure and function of the following features within the ileum. (The first one has been completed for you.) Ileum feature Microvilli Structure Function Projections of the exposed membrane of columnar epithelial cells lining the ileum Increase surface area for the absorption of the products of digestion Crypts of Lieberk hn Goblet cell Lacteal Muscularis mucosa [4] 4680 2 [Turn over 2 The diagrams below show part of a stem and part of a leaf of a hydrophytic plant. Stem epidermis vascular bundle Examiner Only Marks Remark Leaf upper epidermis vascular bundle palisade mesophyll air space air space (a) Explain the presence of the air spaces in the stem. __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [2] (b) Explain two ways in which the leaf exhibits hydrophytic adaptations. 1. ________________________________________________________ __________________________________________________________ 2. ________________________________________________________ _______________________________________________________ [2] 4680 3 [Turn over 3 (a) Distinguish between the terms gross productivity and net productivity . Examiner Only Marks Remark __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [2] Rate of photosynthesis and respiration /arbitrary units (b) The graph below shows the effect of temperature on both the rate of photosynthesis and the rate of respiration in a leaf. Photosynthesis Respiration 0 10 20 Temperature/ C 30 40 Analyse the graph to explain the influence of temperature on the net productivity (growth) of a leaf. __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [3] 4680 4 [Turn over 4 The table below shows three agricultural food chains and the subsequent energy yield available for human consumption. Food chain Example Wheat/wheat products consumed by humans Remark Energy yield for human consumption /103 kJ ha 1 y 1 1. Grassland dairy cows Milk/dairy products humans consumed by humans 2. Cultivated plant crop humans Examiner Only Marks 1356 7800 11 000 3. Intensively farmed Milk/dairy products grassland dairy cows consumed by humans humans 3813 (a) Much of the energy contained in the grass does not go to the cows in food chain 1. Suggest two alternative destinations for this energy. 1. ________________________________________________________ __________________________________________________________ 2. ________________________________________________________ _______________________________________________________ [2] (b) Explain why food chain 2 has a higher energy yield for human consumption than food chain 1. __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [2] (c) Outline one health benefit for humans in food chain 2. __________________________________________________________ _______________________________________________________ [1] 4680 5 [Turn over (d) Outline one possible way in which the productivity of the intensively farmed grassland may have been increased and explain how this method would increase the productivity. Examiner Only Marks Remark __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [2] 4680 6 [Turn over 5 The table below shows the red blood cell counts for a person living at sea level, and the same person after acclimatisation at high altitude in preparation for climbing Mount Everest. Examiner Only Marks Remark Red blood cell count/dm 3 5.0 1012 5.6 1012 At sea level After acclimatisation at high altitude (a) Describe how the partial pressure of atmospheric oxygen varies with altitude. __________________________________________________________ _______________________________________________________ [1] (b) Explain the advantage of having a higher red blood cell count at high altitude. __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [2] People such as the Quechua Indians in the Andes, who live permanently at high altitude, not only have increased red blood cell counts but possess other adaptations for life at high altitude. (c) Describe one other adaptation to life at high altitude which might be expected, and explain how this adaptation aids their survival. __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [2] The increased production of red blood cells is due to the release of the hormone erythropoietin (EPO) in the body. Athletes can inject EPO to artificially stimulate the red blood cell count and so boost performance. (d) Suggest one possible danger to the athlete of an artificially raised blood cell count. __________________________________________________________ _______________________________________________________ [1] 4680 7 [Turn over 6 The diagram below summarises the movement of water through a plant. Examiner Only Marks Remark leaf stem root A-Level Biology by W D Phillips and T J Chilton (OUP, 1989), copyright Oxford University Press, reprinted by permission of Oxford University Press (a) Describe the movement of water through the root cortex and into the xylem vessels. __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [4] 4680 8 [Turn over (b) Describe how the loss of water by evaporation from the leaf creates a sequence of events which leads to its transport up the plant. Examiner Only Marks Remark __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [4] (c) Explain why xylem vessels are lignified. __________________________________________________________ _______________________________________________________ [1] 4680 9 [Turn over 7 The balance between predator and prey populations is rarely stable and may show periodic fluctuations. Examiner Only Marks Remark (a) Explain the effect of an increasing predator population on a prey population. __________________________________________________________ _______________________________________________________ [1] Grey seals, Halichoerus grypus, are predators of a wide range of fish. A study of their feeding behaviour was undertaken in the North Sea during two years, 1985 and 2002. The estimated total amount of fish consumed by the seals was 39 000 tonnes in 1985 and 116 000 tonnes in 2002. The graph below shows the percentage of different prey species taken by the seals in both years. 80 Percentage of total prey 1985 60 2002 40 20 0 4680 Sand eel Cod Haddock Sea scorpion Prey species 10 Plaice Other [Turn over (b) (i) Suggest why the total amount of fish consumed by the grey seals was greater in 2002. Examiner Only Marks Remark ______________________________________________________ ____________________________________________________ [1] (ii) The most common prey of the grey seal is sand eels. Calculate the mass of sand eels consumed by the grey seals in 2002. (Show your working in the space below.) Answer ______________________ [3] (iii) Comment on the relative amounts of the different prey consumed in the two years. ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ ____________________________________________________ [3] 4680 11 [Turn over Section B Examiner Only Marks Remark In this section you are expected to answer in continuous prose, supported, where appropriate, by diagrams. You are reminded that up to two marks in this question are awarded for the quality of written communication. [2] 8 Give an account of the co-ordinated sequence of events which result in the flow of blood through the heart during one cardiac cycle. [10] _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ ____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ 4680 12 [Turn over Examiner Only _____________________________________________________________ Marks Remark _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ ____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ ______________________________________________________________ 4680 13 [Turn [Turn over THIS IS THE END OF THE QUESTION PAPER ASB2S9 ASB2S9 4680 14 [Turn [Turn over ASB2S9 4680 15 [Turn over Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. 938-023-1 4680 16 [Turn over

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Additional Info : Gce Biology June 2009 Assessment Unit AS 2 Module 2: Physiology and Ecology
Tags : General Certificate of Education, A Level and AS Level, uk, council for the curriculum examinations and assessment, gce exam papers, gce a level and as level exam papers , gce past questions and answer, gce past question papers, ccea gce past papers, gce ccea past papers

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