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GCE JAN 2009 : (AS 2) Physiology and Ecology

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Centre Number 71 Candidate Number ADVANCED SUBSIDIARY (AS) General Certificate of Education January 2009 Biology assessing Module 2: Physiology and Ecology ASB21 Assessment Unit AS 2 [ASB21] WEDNESDAY 14 JANUARY, AFTERNOON TIME 1 hour. INSTRUCTIONS TO CANDIDATES 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. Answer all eight questions. You are provided with Photograph 2.2 for use with Question 2 in this paper. Do not write your answers on this photograph. For Examiner s use only Question Number 1 2 INFORMATION FOR CANDIDATES The total mark for this paper is 55. Section A carries 43 marks. Section B carries 12 marks. You should spend approximately 15 minutes on Section B. You are expected to answer Section B in continuous prose. Quality of written communication will be assessed in Section B. Figures in brackets printed down the right-hand side of pages indicate the marks awarded to each question or part question. 4251 3 4 5 6 7 8 Total Marks Marks Section A Examiner Only Marks 1 Remark Use the information in the statements below to identify the plant tissues described. Tissue composed of irregularly sized, living plant cells with thin cell walls made of cellulose. May be used for storage and/or support. ____________________________________________________________ Tissue composed of living, elongated cells with cellulose cell walls. The cell walls are usually thickened at the corners of the cell. Used primarily for support. ____________________________________________________________ Tissue composed of elongated cells with thick, lignified cell walls. The cells, when mature, are dead with adjacent cells interlocking via their tapered, chisel-like ends. Used primarily for support. ____________________________________________________________ A composite or mixed tissue consisting of sieve tube cells, companion cells, parenchymal cells and sometimes fibre cells. Used in the transport of organic molecules around the plant. _________________________________________________________ [4] 4251 2 [Turn over 2 Photograph 2.2 is a photomicrograph of cells in a blood smear. Examiner Only Marks Remark (a) Identify each cell type, A, B and C. A _______________________________________ B _______________________________________ C _______________________________________ [2] (b) Describe two ways in which cell type A is adapted to perform its function efficiently. 1. ________________________________________________________ __________________________________________________________ 2. ________________________________________________________ _______________________________________________________ [2] (c) State the function of each of the other cell types. B ________________________________________________________ C _____________________________________________________ [2] 4251 3 [Turn over 3 The graph below shows changes in energy used, oxygen uptake and blood lactic acid levels for a person at rest, during and after exercise. Rest Number of times greater than normal Exercise After exercise 12 11 10 9 8 7 6 5 4 3 2 1 energy used oxygen intake lactic acid in the blood 0 2 4 6 8 10 12 14 16 18 20 Time after start of exercise/minutes Examiner Only (a) Describe how oxygen intake is increased during exercise. Marks Remark __________________________________________________________ _______________________________________________________ [1] (b) Explain the increase in the level of lactic acid during the exercise period. __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [2] 4251 4 [Turn over (c) Explain why the lactic acid level in the blood continues to rise even after the exercise has stopped. Examiner Only Marks Remark __________________________________________________________ _______________________________________________________ [1] The recovery time can be measured as the time taken, after exercise, for the blood lactic acid to return to the rest (pre-exercise) value. (d) (i) What is the recovery time for this individual? ____________________________________________________ [1] (ii) If such a study were repeated with an athlete who regularly trains, suggest how the athlete s recovery time would compare with your answer above. ______________________________________________________ ____________________________________________________ [1] 4251 5 [Turn over 4 The diagram below represents a pyramid of energy (productivity) for a terrestrial ecosystem. The units are kJ m 2 y 1. Tertiary consumers 805 Primary consumers Remark 92 Secondary consumers Examiner Only Marks 7073 Producers 87 402 Light energy reaching the producers = 4.4 106 (a) Explain how plants are adapted for the absorption of light. __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [3] (b) State one reason why much of the light which reaches the producers is not used in photosynthesis. __________________________________________________________ _______________________________________________________ [1] (c) Calculate the percentage of energy transferred from primary consumers to tertiary consumers. (Show your working in the space below.) Answer ______________ [2] 4251 6 [Turn over BLANK PAGE (Questions continue overleaf) 4251 7 [Turn over 5 The graph below shows the oxygen dissociation curves for the haemoglobin of a shrew and a human. Examiner Only Marks Remark Saturation of haemoglobin with oxygen/% 100 75 Human 50 Shrew 25 0 0 2 4 6 8 Partial pressure of oxygen/kPa 10 12 (a) Use the graph to determine the partial pressure of oxygen which corresponds to 50% saturation of the shrew haemoglobin and the human haemoglobin. Shrew __________________ Human __________________ [2] The shrew is a very small mammal with a large surface area to volume ratio and so loses a proportionally large amount of heat. To compensate for this, the shrew maintains a very high metabolic rate with the result that its oxygen consumption is relatively high. (b) Explain how the shrew is adapted for maintaining a high metabolic rate by having haemoglobin with a lower affinity for oxygen. __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [2] 4251 8 [Turn over (c) Describe and explain the conditions which result in human haemoglobin having a reduced affinity for oxygen. Examiner Only Marks Remark __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [2] 4251 9 [Turn over 6 The shag (Phalacrocorax aristotelis) and the cormorant (Phalacrocorax canbo) are both relatively common birds which live and breed around the coastline and major waterways of Ireland. Both species feed in the same waters and nest in close proximity to each other. The diagrams below represent the head and neck of both birds. shag Examiner Only Marks Remark cormorant Source: Advanced Biology Principles and Applications, CJ Clegg and DG Mackean, John Murray, 1994 (a) What type of competition between these two birds might be predicted? _______________________________________________________ [1] The table below represents the results of a study into the feeding strategies and prey taken by both species. Species Shag Cormorant Feeding location Surface water Bottom water % of prey species taken Sand eels Herring Flatfish Shrimps 33 49 1 2 0 1 26 33 (b) Using the information in the table, explain why there is minimal competition between the shag and cormorant. __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [2] 4251 10 [Turn over (c) (i) Using the information in the question, describe the ecological niche of the cormorant. Examiner Only Marks Remark ______________________________________________________ ______________________________________________________ ______________________________________________________ ____________________________________________________ [2] (ii) Suggest what would happen if both the shag and cormorant shared this niche. ______________________________________________________ ______________________________________________________ ______________________________________________________ ____________________________________________________ [2] 4251 11 [Turn over 7 The diagram below shows a view of the mammalian heart. Examiner Only Marks Remark A B (a) What evidence is there in the diagram that the phase of the cardiac cycle illustrated is diastole? __________________________________________________________ _______________________________________________________ [1] (b) Contraction of the heart is initiated at the SAN (pacemaker). Indicate the location of the SAN on the diagram with an X. [1] (c) Features A and B are involved in transmitting the wave of excitation through the ventricles. Identify A _______________________________________ B _______________________________________ [2] (d) The wave of excitation is delayed by about 0.12 seconds at A. Explain the importance of this delay. __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [2] 4251 12 [Turn over (e) The wave of excitation passes down B directly to the base of the ventricles. Explain the importance of ventricular contraction being initiated from the base. Examiner Only Marks Remark __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [2] 4251 13 [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 processes involved in the movement of water through a plant. [10] _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ 4251 14 [Turn over Examiner Only _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ 4251 15 Marks Remark 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. 935-026-1 16 [Turn over 4251.02 ASB21IN1 A GCE Biology Advanced Subsidiary (AS) Assessment Unit AS 2 Module 2: Physiology and Ecology January 2009 Source: Ed Reschke, Peter Arnold Inc./Science Photo Library Photograph 2.2 (for use with Question 2) B C

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Additional Info : Gce Biology January 2009 Assessment Unit AS 2 Module 2: Physiology and Ecology
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