Cambridge A Level Biology 9700 — 2013 Oct/Nov Paper 3 · Variant 4

This document consists of 12 printed pages and 4 blank pages. DC (SJF/CGW) 57930/7 © UCLES 2013 [Turn over UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Subsidiary Level and Advanced Level READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name on all the work you hand in. Write in dark blue or black ink. You may use a pencil for any diagrams, graphs or rough working. Do not use red ink, 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. * 8 5 9 9 5 8 4 1 9 9 * BIOLOGY 9700/34 Advanced Practical Skills 2 October/November 2013 2 hours Candidates answer on the Question Paper. Additional Materials: As listed in the Confidential Instructions. For Examiner’s Use 1 2 Total

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3 [Turn over 9700/34/O/N/13 © UCLES 2013 For Examiner’s Use You are reminded that you have only one hour for each question in the practical examination. You should: • read carefully through the whole of Question 1 and Question 2 • then plan your use of the time to make sure that you finish all the work that you would like to do. You will gain marks for recording your results according to the instructions. 1 You are provided with an extract from plant cells, which contains a mixture of biological molecules. This extract may contain any of the biological molecules, for example lipids, proteins or types of carbohydrates. Visking tubing, V, is selectively permeable, similar to a cell membrane, so that some biological molecules will diffuse through the wall of the tubing. You are required to investigate the diffusion of biological molecule(s) into the water surrounding the Visking tubing. (a) (i) State which biological molecule(s) might diffuse through the wall of the Visking tubing. …[1] You are provided with: labelled contents hazard volume / cm3 P solution of plant extract none 15 W distilled water none 100 labelled details V 15 cm length of Visking tubing in a beaker containing water

4 9700/34/O/N/13 © UCLES 2013 For Examiner’s Use Fig. 1.1 shows the set-up of the apparatus. paper clip Visking tubing containing P clear beaker or container Fig. 1.1 You must now read up to the end of step 11 before proceeding. Samples of the water surrounding the Visking tubing will be removed at 5 minute intervals for 15 minutes. To compare the diffusion of any single biological molecule at each 5 minute interval the test for the biological molecule needs to be standardised. For example, if you carried out the test for reducing sugars: • one standardised variable is the volume of sample removed from water, e.g. 2 cm3 • the dependent variable is measuring the time taken for the first colour change to appear. (ii) State the other variables which would need to be standardised for the reducing sugars test, using only the reagents and apparatus provided. Describe how you will standardise each variable. … … … … … …[3] Samples of water surrounding the Visking tubing will be removed for testing at 5 minute intervals for 15 minutes. Therefore, you need to take this into account when you decide the volume of water to put into the container.

5 [Turn over 9700/34/O/N/13 © UCLES 2013 For Examiner’s Use Decide: • the test (or tests) you will carry out on the water • the volume of the water you will need to sample for the test (or tests) at each time interval. You may find it helpful to calculate the total volume of water needed for all the tests. (iii) Draw on Fig. 1.1 (on page 4) the level of the water: • before you remove any samples (label this ‘before’) • after the total volume of water needed to sample for all the tests has been removed (label this ‘after’). [2] Proceed as follows: 1. Tie a knot in the Visking tubing as close as possible to one end so that it seals the end. 2. To open the other end, wet the Visking tubing and rub the tubing gently between your fingers. 3. Put 5 cm3 of P into the open end of the Visking tubing. 4. Rinse the outside of the Visking tubing by dipping it into the water in the container labelled V. 5. Put the Visking tubing into a small beaker or container as shown in Fig. 1.1. 6. Make sure the open end of the Visking tubing is held in place by a paperclip. You will start timing as soon as you add W. Read steps 7 to 11 before proceeding. 7. Put W into the small beaker to the level you decided in (iii). 8. Immediately start timing and remove the first sample of water into a separate container to keep for the tests. 9. After 5 minutes, remove the next sample into a different container. 10. Repeat step 9 for two more samples. 11. Use the reagents and apparatus provided to identify the biological molecule(s) that you decided in (a)(i) may be present in the samples.

6 9700/34/O/N/13 © UCLES 2013 For Examiner’s Use (iv) Prepare the space below and record your results. [5] (v) Use the results from (iv) to complete the hypothesis: The Visking tubing allows ………………………………………… to diffuse into the surrounding water. [1] (vi) Explain how the results support your hypothesis. … … …[1]

7 [Turn over 9700/34/O/N/13 © UCLES 2013 For Examiner’s Use (vii) Predict the trend in the results if the time was extended from 15 minutes to 30 minutes. … …[1] (viii) Suggest how you would modify this investigation to investigate the concentration of reducing sugars in P. … … … … … … …[3]

8 9700/34/O/N/13 © UCLES 2013 For Examiner’s Use Some scientists investigated the total sugar content of plant extracts from different types of fruit. The results are shown in Table 1.1. Table 1.1 type of fruit percentage of sugars avocado (A) 0.6 banana (B) 12.2 kiwi (K) 8.0 lemon (L) 2.5 melon (M) 5.9 (b) Plot a chart of the data shown in Table 1.1. [4] [Total: 21]

9 [Turn over 9700/34/O/N/13 © UCLES 2013 For Examiner’s Use 2 The eyepiece graticule scale in your microscope may be used to help draw a plan diagram, as in (a), with the correct shape and proportions of the tissues, without needing to calibrate the eyepiece graticule scale. M1 is a slide of a stained transverse section through part of a tubular organ from an animal. (a) Select a part of the wall of the organ which shows the highest number of different layers of tissues. Draw a large plan diagram of this part of the wall to show the proportions of the different layers of tissues. The outermost layer is smooth and this should be drawn at the top of your diagram. Annotate (make a note with a label line) your diagram to show one other difference between the layers making up the wall. [4]

10 9700/34/O/N/13 © UCLES 2013 For Examiner’s Use Fig. 2.1 is a photomicrograph of a stained transverse section through part of a different tubular organ from the same animal. magnification × 310 Y Fig. 2.1 (b) (i) Use the magnification to calculate the actual length of line Y in μm. You will lose marks if you do not show all the steps in your calculation and do not use the appropriate units. actual length …μm [4] (ii) State one observable feature in Fig. 2.1 which supports the conclusion that substances are absorbed by the tubular organ. Explain how this feature would increase the rate of absorption. … …[1]

11 [Turn over 9700/34/O/N/13 © UCLES 2013 For Examiner’s Use (iii) Prepare the space below so that it is suitable for you to record the observable differences between the specimen on slide M1 and that shown in Fig. 2.1. Record your observations in the space you have prepared. [4]

12 9700/34/O/N/13 © UCLES 2013 For Examiner’s Use Fig. 2.2 is a photomicrograph showing some cells from the lining of a different part of the same tubular organ shown in Fig. 2.1. cell X Fig. 2.2 (c) (i) Similar cells to cell X are found in Fig. 2.1 (on page 10). On Fig. 2.1 (on page 10), use a label line and label to identify one cell which may be the same type as cell X. [1]

13 9700/34/O/N/13 © UCLES 2013 For Examiner’s Use (ii) Make a large drawing of the whole cells shown in the sector marked on Fig. 2.2 (on page 12). On your drawing, use a label line and label to identify one observable feature of these cells which identify them as being eukaryotic cells. [5] [Total: 19]

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16 9700/34/O/N/13 © UCLES 2013 BLANK PAGE Copyright Acknowledgements: Fig. 2.1 © STEVE GSCHMEISSNER/SCIENCE PHOTO LIBRARY. Fig. 2.2 © MANFRED KAGE/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. University of 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.

CAMBRIDGE INTERNATIONAL EXAMINATIONS GCE Advanced Subsidiary Level and GCE Advanced Level MARK SCHEME for the October/November 2013 series 9700 BIOLOGY 9700/34 Paper 3 (Advanced Practical Skills 2), 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 October/November 2013 series for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level components and some Ordinary Level components.

Page 2 Mark Scheme Syllabus Paper GCE AS/A LEVEL – October/November 2013 9700 34 © Cambridge International Examinations 2013 Mark scheme abbreviations: ; separates marking points / alternative answers for the same point R reject A accept (for answers correctly cued by the question, or by extra guidance) AW alternative wording (where responses vary more than usual) underline actual word given must be used by candidate (grammatical variants excepted) max indicates the maximum number of marks that can be given ora or reverse argument mp marking point (with relevant number) ecf error carried forward I ignore

Page 3 Mark Scheme Syllabus Paper GCE AS/A LEVEL – October/November 2013 9700 34 © Cambridge International Examinations 2013 1 (a) (i) reducing sugar or non-reducing sugar or named examples glucose, fructose, sucrose; [1] (ii) vol(ume) of Benedict’s; temp(erature); cm3 or ml(s) + whole number or to 0.5, at least 1, up to 15 + (temperature of Benedict’s waterbath) whole number or to 0.5 80 to 100; [3] (iii) ‘before’ labelled above ‘after’; do not give mark if both levels below the top of Visking tubing which contains P or if both levels drawn above Visking tubing; [2] (iv) organised into table; heading (column to left of data or top row) time (/) min(utes) + (any column / row headed) (observation of) colour (change) or time (to first colour change /) s(econds); records results according to instructions; i.e. for 0, 5, 10, 15 minutes; correct pattern of results between first reading and last; records results for reducing sugar only (ignore non-reducing sugar); recorded either as colour can have only green or yellow or orange or red or brown or any combination; I brick or as whole numbers with units s or sec [5] (v) reducing sugar(s); [1] (vi) [1] idea of at 5 mins + compared to end / 15 mins where no change or negative or more time to change or example of lower colours change in colour or positive or less time to change or example of red or brown; (vii) idea that times would become closer together or about the same or no quicker / faster or more precipitate or more red or darker red or colour changes quicker; [1]

Page 4 Mark Scheme Syllabus Paper GCE AS/A LEVEL – October/November 2013 9700 34 © Cambridge International Examinations 2013 (viii) mp1 (independent variable) (using reducing sugars or named reducing sugar / glucose / standard solutions) at least 5 sugar concentrations or at least five examples of concentrations; mp2 (how made) serial dilution or simple dilution or described method for making different concentrations; mp3 (dependent variable) idea of compare results / colour of plant extracts / samples / unknown with known (standard) solutions; [3] (b) (x-axis) type of fruit + (y-axis) percent(age) or % (of) sugar(s); (x-axis) even bar widths up to 2 cm + (y-axis) 2.0 to 2 cm labelled each 2 cm except label at origin of 0; correct plotting of each bar with • horizontal line • ruled; bars + quality + labels; • bars must have a space between • all vertical bar lines drawn (including on axis if used), meet horizontal line, ruled lines not too thick • any clear labels must be directly below correct bar or inside bar or shaded with key [4] [Total: 21] 2 (a) drawing + quality (plan of stomach wall); do not give mark if • any shading • drawn over print of question • any ruled lines • smaller than 50 mm at widest point on wall • less than 4 lines or 3 lines and 1 enclosed area or if any part of line • is too thick • has any feathery or dashed lines or gap in line • has any overlaps no cells + only part of wall; smooth layer at top + lowest layer is thicker than all other layers; uses label line and correct difference (e.g. lowest layer) thickest or folds; [4]

Page 5 Mark Scheme Syllabus Paper GCE AS/A LEVEL – October/November 2013 9700 34 © Cambridge International Examinations 2013 (b) (i) correct measurement of line Y; 60 or 60.5 or 61 or 61.5 or 62 or 62.5 or 63 or 6(.0) or 6.05 or 6.1 or 6.15 or 6.2 or 6.25 or 6.3; correct precision with mm or with cm; shows length of Y divided by 310; shows correct conversion of either (mm to µm) × 1000 or (cm to µm) × 10 000 [4] (ii) feature + how this would increase absorption; e.g. folds increase surface area [1] (iii) mp1 organise as table with three columns or rows separated by lines + two columns headed M1 / slide and Fig 2.1. in any order + third column or row contains at least one feature; mp feature M1 / slide Fig 2.1 mp2 folds number or spacing more or lots or many close together few(er) or not many or about 2; further apart; mp3 folds shape or length thin(ner) or narrow(er) or long(er) thick(er) or wide(r) or short(er); mp4 (cell) packing or shape close together long or thin(ner) further apart round(er) or thick(er); mp5 number of layers more less or none; mp6 goblet cells / X few(er) or no(ne) or absent more or lots or yes or present; [4] (c) (i) correct label to goblet cell; [1] (ii) drawing and quality; do not give mark if • any shading • drawn over print of question • any ruled lines • smaller than 60 mm across widest point of largest cell • less than 6 outer enclosed areas or if any outer lines of enclosed areas are • too thick • feathery or dashed or gap in line • have tails or overlaps only three whole cells drawn + one goblet cell + drawn as single touching group; (nucleus of cell below goblet cell) touches cell membrane adjacent to goblet cell + triangular area; triangular area drawn under goblet cell; uses label line and labels nucleus; [5]