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GCE JAN 2009 : (AS 3) Practical Processes

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Centre Number 71 Candidate Number ADVANCED SUBSIDIARY (AS) General Certificate of Education January 2009 Biology assessing Module 3A: Practical Processes ASB31 Assessment Unit AS 3A [ASB31] THURSDAY 22 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 five questions. You are provided with Photograph 3.2 for use with question 2 in this paper. Do not write your answers on this photograph. INFORMATION FOR CANDIDATES The total mark for this paper is 50. Quality of written communication will be assessed in questions 3(c), 4(c) and 5(b) (denoted in the paper with an asterisk, *) and awarded a maximum of 2 marks. Figures in brackets printed down the right-hand side of pages indicate the marks awarded to each question or part question. For Examiner s use only Question Number 1 2 3 4 5 QWC Total Marks 4250 Marks 1 (a) Four test tubes each contained a solution of a single carbohydrate, fructose, glucose, sucrose and starch. Examiner Only Marks Remark The test tubes were labelled A to D and, in order to identify the carbohydrate present in each tube, a series of tests was carried out. 1. Samples from all four tubes were tested with iodine solution. Tube B tested positive. 2. Samples from the remaining three tubes were tested with Clinistix. Tube A tested positive. 3. Samples from the remaining two tubes were tested using Benedict s test. Tube D tested positive. The remaining tube can be identified by elimination. (i) Using the test results shown above, identify the carbohydrate in each of tubes A to D, and complete the table below. Tube Carbohydrate A B C D [3] (ii) Complete the table below to indicate a positive result for each test. Test Positive result Iodine Clinistix Benedict s [2] (b) Sugars, particularly sucrose, are added to soft drinks as sweeteners though not all sugars impart the same level of sweetness. Glucose has only 75% of the sweetness of sucrose but fructose is twice as sweet as glucose. Determine how much fructose must be added to replace 30 g of sucrose. (Show your working.) Answer ______________ g [2] 4250 2 [Turn over 2 Photograph 3.2 is a photomicrograph of part of a transverse section through the root of a buttercup (Ranunculus). In the space below, draw a block diagram to show the tissue layers in the root as shown in the photograph. Label the drawing to identify at least five structures. Examiner Only Marks Remark [9] 4250 3 [Turn over 3 An experiment was undertaken to investigate the synthesis of starch from glucose-1-phosphate by the enzyme starch phosphorylase extracted from potato. Examiner Only Marks Remark The flow diagram below summarises the procedure used. Potato pulp is centrifuged to remove starch Potato extract is added to the solution of glucose-1-phosphate Samples are taken every minute and added to dilute iodine solutions Cuvettes are filled with the mixture and placed in a colorimeter with a red filter Before each reading is taken, the colorimeter is standardised to give a 100% transmission For each mixture the % transmission in the colorimeter is read (a) State which two volumes need to be controlled during the experiment. 1. _______________________________________________________ 2. ____________________________________________________ [2] (b) Explain each of the following steps in the procedure. why the potato extract is centrifuged to remove starch _____________________________________________________ _____________________________________________________ why samples are added to iodine solution _____________________________________________________ _____________________________________________________ why a red filter is used in the colorimeter _____________________________________________________ _____________________________________________________ how the colorimeter is standardised to give 100% transmission _____________________________________________________ __________________________________________________ [4] 4250 4 [Turn over *(c) The results of the experiment are shown in the graph below. Examiner Only Remark % transmission Marks time Explain the shape of the curve obtained. _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [3] 4250 5 [Turn over 4 Three species of ground beetle were sampled at 10 metre intervals along a transect. The transect passed from an area of dense oak woodland to an open area of grassland. The results are shown in the table below. Position along the transect/m Habitat 0 Examiner Only Marks Remark Numbers of ground beetles Species A Species B Species C Oak woodland 4 4 28 10 Oak woodland 4 7 22 20 Oak woodland 3 18 16 30 Grassland 28 13 4 40 Grassland 15 2 0 50 Grassland 16 3 0 60 Grassland 18 1 0 (a) Suggest a technique by which the beetles may have been sampled. ______________________________________________________ [1] (b) Plot the above results, using an appropriate graphical technique. (Use the graph paper opposite.) [7] *(c) Describe the distribution of the species of ground beetle as evident in the results. _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [3] (d) Suggest reasons for the differences in the distribution of the beetles. _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] 4250 6 [Turn over 4250 7 [Turn over 5 You are asked to plan an investigation to determine Examiner Only Marks Remark which of two plant tissues, from the roots of carrot and parsnip, has the lower water potential You are provided with the following. carrot and parsnip roots distilled water and sucrose solutions, 0.1 to 1.0 mol dm 3 small stoppered bottles cork borer, razor blade, filter paper general laboratory apparatus (a) Parsnip tastes sweeter than carrot. On the basis of this information, which of the two tissues would you expect to have the lower water potential? Explain your reasoning. _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] *(b) Outline the major steps that you undertake to determine the water potential of each tissue. _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [5] 4250 8 [Turn over (c) Decribe one major source of error which may be encountered during the investigation. Examiner Only Marks Remark _________________________________________________________ ______________________________________________________ [1] (d) Distinguish between the terms accuracy and reliability of results. _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] Quality of written communication [2] THIS IS THE END OF THE QUESTION PAPER 4250 9 935-034-1 4250 12 [Turn over GCE Biology Advanced Subsidiary (AS) Assessment Unit AS 3A Module 3A: Practical Processes January 2009 Photograph 3.2 Source: Herve Conge, ISM/Science Photo Library 4250.02 ASB31IN1 (For use with Question 2)

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Additional Info : Gce Biology January 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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