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GCE JUN 2009 : (AS 3) Practical Processes

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1 2 Centre Number 3 71 4 5 Candidate Number 6 ADVANCED SUbSIDIARy (AS) General Certificate of Education 2009 7 8 9 biology 11 Assessment Unit AS 3A 12 assessing 13 Module 3A: Practical Processes 14 ASB31 10 [ASb31] 15 FRIDAy 12 JUNE, AFTERNOON 16 17 18 19 TIME 1 hour. 20 21 INSTRUCTIONS TO CANDIDATES Write your Centre Number and Candidate Number in the spaces 22 provided at the top of this page. 23 Write your answers in the spaces provided in this question paper. Answer all five questions. 24 You are provided with Photograph 3.2 for use with Question 2 in this 25 26 27 28 paper. Do not write your answers on this photograph. Question Number INFORMATION FOR CANDIDATES The total mark for this paper is 50. 29 Quality of written communication will be assessed in questions 3(c)(i), 4(b) and 5(b) (denoted in the paper with an asterisk, *), and awarded a maximum of 2 marks. 31 Figures in brackets printed down the right-hand side of pages indicate the marks awarded to each question or part question. 30 32 33 34 35 For Examiner s use only 1 2 3 4 5 QWC Total Marks 4681 Marks 1 Chromatography was used to separate three mixtures of sugars, A, B and C. The mixtures contained the following. Examiner Only Marks Remark A fructose, glucose, maltose and sucrose B products of hydrolysis of maltose C products of hydrolysis of sucrose The diagram below shows the results. solvent front 1 2 3 4 spotting line A B C (a) Maltose has an Rf value of 0.33. Determine which of the spots, 1 to 4 from mixture A represents maltose. (Show your working in the space below.) Answer _______ [2] 4681 2 [Turn over (b) Identify the other three spots from mixture A in the chromatogram. Explain your answers. Examiner Only Marks Remark Identification __________________ __________________ __________________ Explanation _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [3] (c) The chromatogram was cut up so that each of the sugars, 1 to 4 from mixture A, was on a different piece of paper. Each of these was then added to a separate test tube containing some water to dissolve the sugar from the paper. Explain how a simple biochemical test could be used to determine which of the four sugars is a non-reducing sugar. _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] 4681 3 [Turn over 2 Photograph 3.2 is a photomicrograph of a transverse section through a leaf of the tobacco plant (Nicotiana tabacum). The tobacco leaf has some xerophytic adaptations. In the space below, draw a block diagram to show the tissue layers in the leaf as shown in the photograph. Annotate the drawing to identify two xerophytic features and, in each case, explain how the feature acts as an adaptation. Examiner Only Marks Remark [9] 4681 4 [Turn over BLANK PAGE (Questions continue overleaf) 4681 5 [Turn over 3 A potometer is a device for investigating the rate of transpiration. Prior to setting up, the potometer and the stem of a leafy shoot are immersed in water. Under water, the bottom centimetre of the stem is cut off and the cut end inserted into the plastic tubing. The apparatus is removed from the water, a bubble of air allowed to enter the open end of the capillary tube and that end then inserted into a beaker of water. The completed set-up for a simple potometer is shown below. Examiner Only Marks Remark vaseline plastic tubing three-way tap syringe full of water capillary tube bubble of air beaker of water Reproduced with the permission of Nelson Thornes Ltd from Practical Advanced Biology by Tim King & Michael Reiss with Michael Roberts ISBN 0174483082 first published in 2001 (a) What assumption is made when this apparatus is used to investigate the rate of transpiration? _________________________________________________________ ______________________________________________________ [1] 4681 6 [Turn over (b) Explain each of the following. Examiner Only Marks Remark why it is necessary to cut the leafy shoot and fit it into the potometer under water _________________________________________________________ _________________________________________________________ how the bubble of air is introduced into the capillary tube _________________________________________________________ _________________________________________________________ why a syringe is attached _________________________________________________________ _________________________________________________________ why the set-up is left for 15 minutes before taking readings _________________________________________________________ ______________________________________________________ [4] 4681 7 [Turn over (c) The table below shows some results recorded using the apparatus. Examiner Only Marks Remark Distance travelled by bubble/mm Time/minutes Normal room conditions Covered with clear plastic bag Covered with black plastic bag 0 0 0 0 2 18 10 4 4 36 19 8 6 55 29 11 8 74 38 15 10 90 48 18 * (i) Explain, as fully as possible, the results obtained. ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ ______________________________________________________ ___________________________________________________ [3] (ii) In normal room conditions, the distance moved by the bubble was 90 mm during 10 minutes. The capillary tube has a cross sectional area of 0.8 mm2. Calculate the rate of movement in mm3 minute 1. (Show your working in the space below.) Answer _________ mm3 minute 1 [2] 4681 8 [Turn over (d) In experiments using a potometer it is usual to use the same shoot throughout. Give one limitation of using different shoots in the potometer when investigating the rate of transpiration. Examiner Only Marks Remark _________________________________________________________ ______________________________________________________ [1] 4681 9 [Turn over 4 Mayfly are common insects found in aquatic habitats. The adult lays eggs into water and these develop into larvae which remain aquatic for a year. Mayfly larvae have six legs each with a claw, three tails and gills along their abdomen through which they obtain oxygen from the water. Examiner Only Marks Remark A guide to freshwater invertebrate animals by T T Macan, published by Longmans, 1959, ISBN 058232274X, reproduced with the permission of Pearson Education Ltd, publishers. Using a standardised sampling technique the numbers of mayfly larvae were determined at 10 sites along a stream. The speed of the water current was also estimated at each site. The results are shown in the table below. Number of mayfly larvae 37 31 14 48 36 6 19 42 8 21 Current speed /cm s 1 72 66 31 94 79 19 59 91 12 42 (a) Plot the above results, using an appropriate graphical technique. (Use the graph paper opposite.) [6] * (b) Describe the trend shown in the graph, and suggest an explanation for the trend. _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [3] (c) What problem would the mayfly larvae have to overcome in fast flowing streams? Suggest an adaptation that they might possess to overcome this problem. _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] 4681 10 [Turn over 4681 11 [Turn over 5 You are asked to devise a plan to investigate Examiner Only Marks Remark the effect of substrate concentration on the activity of urease Urease is an enzyme which catalyses the reaction urea ammonia + carbon dioxide The ammonia produced may be estimated using ammonia test strips. After being dipped in a solution containing ammonia, the test strip will produce a colour varying from straw to blue-green. This test colour is compared with a colour chart which equates to ammonia levels 1 (no ammonia) to 7 (high level of ammonia). For the investigation you are supplied with 2% urea solution 0.2% urease solution ammonia test strips general laboratory apparatus (a) State the Independent variable ______________________________________ Dependent variable ____________________________________ [2] * (b) Describe your plan for carrying out the investigation. _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [4] 4681 12 [Turn over (c) Suggest one possible limitation in your method. Examiner Only Marks Remark _________________________________________________________ ______________________________________________________ [1] (d) Distinguish between control experiment and controlled variables with respect to this investigation. _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] (e) Describe how you would increase the reliability of the results. _________________________________________________________ ______________________________________________________ [1] Quality of written communication [2] THIS IS THE END OF THE QUESTION PAPER 4681 13 [Turn over 4681.02 ASB31IN1 GCE Biology Advanced Subsidiary (AS) Assessment Unit AS 3A Module 3A: Practical Processes Summer 2009 (for use with Question 2) Photograph 3.2 Source: Sinclair Stammers/Science Photo Library 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. 937-007-1 4681 16 [Turn over

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Additional Info : Gce Biology June 2009 Assessment Unit AS 3 Module 3A: Practical Processes
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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