Cambridge IGCSE Biology (BES) 0438 — 2013 May/June Paper 5 · Variant 3

This document consists of 13 printed pages and 3 blank pages. IB13 06_0438_53/FP © UCLES 2013 [Turn over *8003549956* For Examiner's Use 1 2 3 Total UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education Biology (US) 0438/53 Paper 5 Practical Test May/June 2013 1 hour 15 minutes Candidates answer on the Question Paper. Additional Materials: As listed in the Confidential Instructions. READ THESE INSTRUCTIONS FIRST Write your Center number, candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use a pencil for any diagrams or graphs. Do not use staples, paper clips, highlighters, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. Electronic calculators may be used. You may lose marks if you do not show your working or if you do not use appropriate units. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question.

2 © UCLES 2013 0438/53/M/J/13 For Examiner's Use 1 You are going to investigate the effect of enzyme concentration on starch. (a) You are provided with a Petri dish containing a layer of starch agar jelly. Three small holes have been cut in the starch agar jelly as shown in Fig. 1.1. The three pieces of starch agar jelly, removed from these holes, are presented on a white tile. P Q R Petri dish starch agar jelly hole in the starch agar jelly Fig. 1.1 • Remove the film from the white tile and add a drop of dilute iodine solution to each piece of starch agar jelly. (i) Describe your observations. [1] You have been provided with two enzyme solutions, labeled 1 and 2. These are different concentrations of the same enzyme. • Remove the lid of the Petri dish. Label the holes P, Q and R on the outside of the Petri dish, as shown in Fig. 1.1. • Carefully put two drops of enzyme solution 1 into hole P. Do not over fill the hole. • Carefully put two drops of enzyme solution 2 into hole Q. Do not over fill the hole. • Carefully put two drops of water into hole R. Do not over fill the hole. • Replace the lid on the Petri dish. • Record the time … Leave the Petri dish for 15 minutes. While you are waiting begin work on parts (b) and (c).

3 © UCLES 2013 0438/53/M/J/13 [Turn over For Examiner's Use • After 15 minutes remove the Petri dish lid. • Wash the surface of the starch agar jelly in the Petri dish with water. Pour the water into the container labeled waste. • Pour dilute iodine solution onto the starch agar jelly at one side of the Petri dish. Tilt the Petri dish so that the iodine solution flows to the opposite side of the dish and covers all of the surface of the starch agar jelly, as shown in Fig. 1.2. starch agar jelly dilute iodine solution dilute iodine solution flows over all of the surface of the starch agar jelly Petri dish tilted by lifting one side Fig. 1.2 • Immediately pour the dilute iodine solution from the surface of the Petri dish into the container labeled waste. • Wash the surface of the starch agar jelly with water. If you require more water, raise your hand. Pour the water into the container labeled waste. • Leave the Petri dish for 1 minute. • Hold the Petri dish up to the light and examine the starch agar jelly.

4 © UCLES 2013 0438/53/M/J/13 For Examiner's Use (ii) Make a drawing to show the appearance of the surface of the starch agar jelly on Fig. 1.3. Include labels. P Q R P R Q Fig. 1.3 [4] (iii) Explain the observations you have drawn in (a)(ii). [3]

5 © UCLES 2013 0438/53/M/J/13 [Turn over For Examiner's Use (iv) Suggest the name of the enzyme used in this investigation. [1] (v) State why water was added to hole R. [1] (b) Germinating seeds produce enzymes that change stored food into soluble materials. Suggest a method similar to that in (a) that you would use to find out if germinating pea seeds produce the same enzyme as in enzyme solutions 1 and 2. [4]

6 © UCLES 2013 0438/53/M/J/13 For Examiner's Use (c) You are provided with a pea seedling. Remove the film from the pea seedling. Make a large, labeled drawing of the pea seedling. [4]

7 © UCLES 2013 0438/53/M/J/13 [Turn over Question 1 continues on page 8.

8 © UCLES 2013 0438/53/M/J/13 For Examiner's Use (d) Fig. 1.4 shows pea seeds in a pod. pod pea seeds Fig. 1.4 The number of pea seeds in a pod varies. Two students picked a sample of 23 pods. They opened the pods and counted the number of pea seeds. Fig. 1.5 shows the students’ results. number of pea seeds in each pod 8, 10, 11, 10, 9, 11, 9, 4, 10, 11, 12, 10, 10, 11, 8, 12, 10, 9, 11, 8, 10, 9, 12 Fig. 1.5

9 © UCLES 2013 0438/53/M/J/13 [Turn over For Examiner's Use (i) Complete Table 1.1 using the results from Fig. 1.5 to show how many pods there were with each number of pea seeds. Two rows have been completed for you. Table 1.1 number of pea seeds in each pod tally number of pods 4 5 6 7 8 /// 3 9 10 //// // 7 11 12 [2] (ii) Draw a histogram on Fig. 1.6 to show the number of pods with each number of pea seeds. [4] Fig. 1.6 (iii) Put an X in the bar on the graph which seems to be anomalous. [1]

10 © UCLES 2013 0438/53/M/J/13 For Examiner's Use (iv) Most pods contained 10 or 11 pea seeds. Suggest a reason for some pods containing 8 or 12 pea seeds. [1] [Total: 26] 2 Fig. 2.1 shows an arthropod. S T × 2.5 Fig. 2.1 (a) You are going to calculate the actual length of the part of the leg that is marked ST in Fig. 2.1. Measure the length of line ST. length of line ST mm Calculate the actual length of the part of the leg that is marked ST. Show your working. actual length of leg mm [3]

11 © UCLES 2013 0438/53/M/J/13 [Turn over For Examiner's Use (b) Use features, visible in Fig. 2.1, to identify the group of arthropods to which this animal belongs. Give two reasons for your answer. group reason 1 reason 2 [3] [Total: 6]

12 © UCLES 2013 0438/53/M/J/13 For Examiner's Use 3 (a) Fig. 3.1 shows a section of a dicotyledonous root as seen with a microscope. Fig. 3.1 On Fig. 3.1: draw a line to a root hair cell and label it; draw a line to a cortex cell and label it. [2]

13 © UCLES 2013 0438/53/M/J/13 For Examiner's Use (b) When stems have just been cut, drops of liquid often appear on the cut surface of the stem. A dicotyledonous stem was cut and the liquid was collected and tested for: • water; • reducing sugar; • protein; • fat. The results are shown in Table 3.1. Complete Table 3.1 to show the reagents and final colors. Table 3.1 results substance reagent initial color final color positive or negative (
or  ) water cobalt chloride blue
reducing sugar blue
protein blue  fat ethanol + water colorless  [6] [Total: 8]

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16 Copyright Acknowledgements: Question 3 Fig. 3.1 © Ref: C003 / 4134; Broad bean root, light micrograph; Dr Keith Wheeler, Science Photo Library. Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge. © UCLES 2013 0438/53/M/J/13 BLANK PAGE

CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education MARK SCHEME for the May/June 2013 series 0438 BIOLOGY (US) 0438/53 Paper 5 (Practical Test), maximum raw mark 40 This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge will not enter into discussions about these mark schemes. Cambridge is publishing the mark schemes for the May/June 2013 series for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level components and some Ordinary Level components.

Page 2 Mark Scheme Syllabus Paper IGCSE – May/June 2013 0438 53 © Cambridge International Examinations 2013 Mark schemes will use these abbreviations • ; separates marking points • / alternatives • R reject • A accept (for answers correctly cued by the question) • I ignore as irrelevant • ecf error carried forward • AW alternative wording (where responses vary more than usual) • AVP alternative valid point • ORA or reverse argument • OWTTE or words to that effect • underline actual word given must be used by candidate (grammatical variants excepted) • ( ) the word / phrase in brackets is not required but sets the context • D, L, T, Q quality of: drawing / labelling / • table / detail as indicated • max indicates the maximum number of marks

Page 3 Mark Scheme Syllabus Paper IGCSE – May/June 2013 0438 53 © Cambridge International Examinations 2013 Answer Marks Guidance for Examiners 1 (a) (i) Yellow/orange to blue/black; [1] Check Supervisor’s Report. (ii) Zone drawn around P/Q; Label clear zone; Zone around P larger than Q; Measurement recorded; No zone around R; [max 4] Check Supervisor’s Report. If Report indicates otherwise – both equal accept. (iii) Explanation: – R no clear zone but P and Q do; Therefore enzyme must break down starch; P must have more (concentrated) enzyme (as wider clear area); Q has less enzyme in the water to breakdown starch; to produce clear areas ; no enzyme – no breakdown of starch/water does not contain enzyme /AW; [max 3] Accept ‘iodine changed since starch not broken down’. Ignore ‘growth’. (iv) amylase/carbohydrase; [1] (v) For comparison/control; [1] Accept to see result without enzyme. (b) 1. remove testa/germinate peas; 2. preparation of ‘enzyme from seed; 3. leave for 15 mins and then add iodine solution; 4. look for colour change/black to clear; 5 repeat for reliability/or to calculate an average; 6 controlled variable; [max 4] For example: place pea on plate/grind up with specified volume of water to extract enzyme and place in hole in starch agar jelly/cut the seed in half/AW; Accept idea of set time period. 1h max. Same size of pea/same species/same type/AW.

Page 4 Mark Scheme Syllabus Paper IGCSE – May/June 2013 0438 53 © Cambridge International Examinations 2013 (c) O – outline; S – size; D – detail – show side root developing and split testa; one label from: testa/radicle/plumule/cotyledon; [4] Whole page allowed for drawing. Check Supervisor’s Report – living specimen provided. Larger than Fig 101 mm+ Not seed/shoot/root. (d)(i) number of pea seeds in each pod tally number of pods 4 / 1 5 0 6 0 7 0 8 already completed 3 9 //// 4 10 already completed 7 11 //// 5 12 /// 3 [2] Accept blank or 0 for 5 to 7 seeds in pod. One for correct tally and number of pods. All boxes correct – 2 marks. 1 error in tally and ecf for number of pods – 1 mark. 2 or more errors – no marks. Place ticks under the columns. (ii) A- axes – labelled and evenly scaled; S – size to fill more than ½ of grid; P – plotting accurate; C- columns of equal width and touching [4] x axis – number of seeds in pod and y axis number of pods. Label of number be central under column. If axes reversed max 3 for S, P and C A Within ± 1mm. ecf from tally table. If columns do not make contact.no C If line graph Max 2 – A and S only. (iii) X in bar for 4 peas [1] (iv) variation (genetic or environmental); [1] A not all peas fertilised in pod/mutation/change in weather eg very dry/cold/less nutrients/AW. I ‘not counting correctly’. [Total: 26]

Page 5 Mark Scheme Syllabus Paper IGCSE – May/June 2013 0438 53 © Cambridge International Examinations 2013 2 (a) length of line 10 mm; formula – ST length ÷ magnification 10/2.5 ; actual length of leg – 4.0 mm; [3] A ± 1 mm. A word formula 3.6, 4.0, or 4.4 mm if line ST is 9, 10 or 11 mm. (b) Group - arachnid/arachnida/spiders; reasons – eight/8 legs/4 pairs of leg; two/2 parts to body/cephalothorax and abdomen; [3] If incorrect group – allow one feature for that group visible in Fig. Ignore negative features/ref to teeth/2 segments. Accept 2 parts to body. [Total: 6] 3 (a) label to root hair cell; label to cortical cell; [2] Line needed to indicate cell. (b) substance reagent results initial colour final colour positive or negative (√ or x) water cobalt chloride blue pink; √ reducing sugar Benedict’s ; blue orange / red; √ protein biuret; blue blue /AW; x fat ethanol + water colourless clear / colourless x [6] One mark per box. A green yellow/yellow R mauve as it is the positive result for the presence of protein. [Total: 8]