Cambridge A Level Biology 9700 — 2014 Oct/Nov Paper 3 · Variant 4

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 pen. You may use an HB pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, 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. * 3 0 5 6 9 3 1 1 4 1 * BIOLOGY 9700/34 Advanced Practical Skills 2 October/November 2014 2 hours Candidates answer on the Question Paper. Additional Materials: As listed in the Confidential Instructions. For Examiner’s Use 1 2 Total This document consists of 13 printed pages and 3 blank pages. DC (NH/CGW) 70254/3 © UCLES 2014 [Turn over Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level

2 9700/34/O/N/14 © UCLES 2014 Before you proceed, read carefully through the whole of Question 1 and Question 2. Plan the use of your 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. If you have enough time, consider how you can improve the accuracy of your results, for example by obtaining and recording one or more additional measurements. 1 Blood plasma contains the protein albumin. The concentration of albumin in a person’s blood may be measured to identify health problems. You are required to estimate, as accurately as possible, the concentration of albumin in a sample of blood plasma, U, by: • carrying out a trial using the concentrations of albumin solutions P1 and P2 • using the results of the trial prepare further concentrations of albumin solution • obtaining more readings, so that you can estimate more accurately the concentration of albumin solution in U. The albumin concentration can be measured by using potassium hydroxide solution and copper sulfate solution. Fig. 1.1 shows the result of adding potassium hydroxide solution and copper sulfate solution to a sample containing albumin. A L B U M I N potassium hydroxide solution (colourless) proteins in sample (purple) then add copper sulfate solution (pale blue) Fig. 1.1

3 9700/34/O/N/14 © UCLES 2014 [Turn over You are provided with: labelled contents hazard volume / cm3 K potassium hydroxide solution harmful irritant corrosive 20 C copper sulfate solution harmful 20 P1 0.8% albumin solution none 40 P2 1.6% albumin solution none 40 U blood albumin sample none 20 W distilled water none 120 You are advised to wear safety glasses or goggles, especially when using the potassium hydroxide, K. If potassium hydroxide, K, comes into contact with your skin, wash it off with plenty of cold water. Question 1 continues on page 4

4 9700/34/O/N/14 © UCLES 2014 Read step 1 to step 6 before proceeding. Proceed as follows: You are required to estimate the concentration of U using P1, P2 and W. 1. Put 1 cm3 of the sample to be tested (for example, P1) into a test-tube. 2. Put 1 cm3 of K into the same test-tube. Shake gently to mix. 3. Put 1 cm3 of C into the same test-tube. Shake gently to mix. 4. Repeat steps 1 to 3 to test P2, U and W. 5. Record your colour observations. 6. In a test-tube rack put the test-tubes in an order which will enable you to record each colour as a number using the scale shown in Fig. 1.2. Use Fig. 1.3 to help you with the colours. 0 1 2 3 4 5 6 7 8 9 10 no purple darkest blue purple Fig. 1.2 Fig. 1.3 shows an example of no purple (0) and an example of darkest purple (10). no purple 0 darkest purple 10 Fig. 1.3

5 9700/34/O/N/14 © UCLES 2014 [Turn over (a) (i) Prepare the space below to record your colour observations and the number using the scale shown in Fig. 1.2. [4] (ii) Complete the following by using one of the words ‘more’ or ‘less’. You may use each word once or more than once. U is … concentrated than 0.8% (P1). U is … concentrated than 1.6% (P2). Use your results to estimate the concentration of albumin in U. …[1] (iii) State which solution P1 or P2 you will dilute to prepare further concentrations. Explain the reason for your decision. … …[2] (iv) Complete Fig. 1.4 on page 6 to show how you will dilute the solution you decided on in (iii) to prepare a serial dilution. You should use the two beakers shown in Fig. 1.4 and add as many extra beakers as you need to prepare a serial dilution.

6 9700/34/O/N/14 © UCLES 2014 You will need to prepare 10 cm3 of each solution. For each beaker, complete Fig. 1.4 to show how you will dilute the solution you decided on in (iii) by: • showing under each beaker the concentration and volume of the solution prepared in this beaker • using one arrow, with a label above the beaker, to show the concentration and volume of albumin solution added • using another arrow, with a label above the beaker, to show the volume of water added. … … … … Fig. 1.4 [3]

7 9700/34/O/N/14 © UCLES 2014 [Turn over 7. Prepare all the concentrations of albumin solution, as shown in Fig. 1.4, in the containers provided. 8. Repeat steps 1 to 3 (page 4) with each of the solutions. 9. Repeat steps 5 and 6 (page 4). (v) Prepare the space below to record your colour observations and the number using the scale shown in Fig. 1.2 (page 4). [2] (vi) Using these additional results from (v) state a more accurate estimate of the concentration of albumin in U. …[1] (vii) Replicating the investigation would increase the confidence in the accuracy of your estimate. Describe one other modification which would increase the confidence in your estimate. … …[1]

8 9700/34/O/N/14 © UCLES 2014 You are required to use a sharp pencil for charts. (b) Scientists have investigated the albumin concentration in the blood plasma of 166 people. The results are shown in Table 1.1. Table 1.1 albumin concentration in blood plasma / g per 100 cm3 frequency / number of people 3.1 – 3.5 3 3.6 – 4.0 21 4.1 – 4.5 42 4.6 – 5.0 60 5.1 – 5.5 39 5.6 – 6.0 1 (i) Plot a chart of the data in Table 1.1. [4]

9 9700/34/O/N/14 © UCLES 2014 [Turn over (ii) Suggest one reason for the pattern of the results shown in the chart. … …[1] (iii) The concentration of albumin in a person’s blood may be measured to identify health problems. One of the reasons for a health problem is that blood albumin has a low solubility in water. Suggest one health problem which may be caused by an albumin concentration of 5.6–6.0 g per 100 cm3. … … …[1] [Total: 20]

10 9700/34/O/N/14 © UCLES 2014 You are required to use a sharp pencil for drawings. 2 L1 is a slide of a stained transverse section through a leaf. This plant species grows widely including Europe, Africa and Asia. You are not expected to be familiar with this specimen. To help draw a plan diagram with the correct shape and proportions of the tissues, an eyepiece graticule can be used to measure the layers of tissues, without the need to calibrate the eyepiece graticule scale. (a) (i) Draw a large plan diagram of the part of the specimen on L1 indicated by the shaded sector in Fig. 2.1. Fig. 2.1 On your diagram: • ignore the trichomes (either attached or loose) • use one ruled label line and label to show the palisade layer. [5]

11 9700/34/O/N/14 © UCLES 2014 [Turn over (ii) Select one whole trichome: • made up of at least three cells • attached to at least one epidermal cell. Make a large drawing of this trichome attached to at least one epidermal cell. Use one ruled label line and label to show one nucleus. [4]

12 9700/34/O/N/14 © UCLES 2014 (b) Fig. 2.2 is a photomicrograph of a stained transverse section through another species of leaf. X 566 +m Fig. 2.2 (i) Prepare the space below so that it is suitable for you to show the observable differences between the specimens shown on L1 and Fig. 2.2. Record your observations in the space you have prepared. [4]

13 9700/34/O/N/14 © UCLES 2014 (ii) Calculate the actual length of the fold shown by line X, using the scale bar. You may lose marks if you do not show your working or if you do not use appropriate units. actual length …[4] (iii) Describe how you would obtain the mean maximum actual length of the folds in the specimen shown in Fig. 2.2. … … … … …[2] (iv) Suggest one observable feature, other than trichomes, shown by both the specimen on L1 and the specimen in Fig. 2.2 which supports the conclusion that these plants grow in dry conditions. Explain how this feature may help the plants grow in dry conditions by preventing water loss. feature … explanation … …[1] [Total: 20]

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® IGCSE is the registered trademark of Cambridge International Examinations. CAMBRIDGE INTERNATIONAL EXAMINATIONS Cambridge International Advanced Subsidiary and Advanced Level MARK SCHEME for the October/November 2014 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 2014 series for most Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level components.

Page 2 Mark Scheme Syllabus Paper Cambridge International AS/A Level – October/November 2014 9700 34 © Cambridge International Examinations 2014 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 accepted) 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 Cambridge International AS/A Level – October/November 2014 9700 34 © Cambridge International Examinations 2014 1 (a) (i) organised into table with all columns separated by a line + all headings underlined ; headings (top or to left of data) sample + (any column / row headed) scale ; result for P1 is a lower number than P2 ; result for W is 0 ; [4] (ii) U is less concentrated than P1 and P2 + U is less than 0.8% ; [1] (iii) P1 ; U lower scale number than P1 ; [2] (iv) at least four further concentrations of E + % ; shows transfer of 10 of P from previous beaker to three beakers + cm3 ; adds 10 of water to three beakers + cm3 ; [3] (v) records colours + numbers for at least three concentrations ; records correct trend for concentrations ; [2] (vi) correct estimate of U ; [1] (vii) colorimeter ; [1] (b) (i) 1 (x-axis) albumin concentration + g per 100 cm3 (y-axis) frequency + number of people ; 2 (x-axis) bars of equal width (y axis) 2 cm to 10 number of people labelled each 2 cm except origin and 60 ; 3 correct plotting of bars in order of the table ; 4 six bars + ruled sharp vertical and horizontal lines ; [4] (ii) people with different health or sex or age or metabolism ; [1] (iii) albumin slows blood circulation or causes osmotic or kidney problems ; [1] [Total 20]

Page 4 Mark Scheme Syllabus Paper Cambridge International AS/A Level – October/November 2014 9700 34 © Cambridge International Examinations 2014 2 (a) (i) 1 at least three lines + size at least 40 mm at widest point + no shading ; 2 no cells drawn + one curved end ; 3 epidermis drawn as two lines ; 4 at least two vascular bundles drawn ; 5 label + line to palisade layer ; [5] (ii) 1 at least four whole cells + largest epidermal cell at least 40 mm at widest point + sharp continuous outer lines ; 2 at least one epidermal cell + at least three cells for trichome ; 3 cell walls as double line with middle lamella between ; 4 line to nucleus ; [4] (b) (i) 1 organise as a table with 3 columns + two columns headed L1 and L2 + one column with at least one feature ; (feature) L1 Fig 2.2 2 trichome has trichomes on both surfaces trichomes on one surface ; 3 folds no folds / absent / no / (only) 1–3 / less / fewer has fold / present / yes ; 4 vascular bundles number less / few(er) more / many ; 5 vascular bundles position not in folds / only in midrib one in each fold ; 6 xylem small(er) large(r) ; 7 air spaces or packing of cells large / many / present or cells loosely packed smaller / fewer / absent or cells densely packed ; 8 cuticle thick(er) / thin(ner) thick(er) / thin(ner) ; [max 4] (ii) 1 measure scale bar + line + units ; 2 566 divided by measurement of scale bar or length of line divided by length of scale bar or length of scale bar divided by 566 ; 3 measurement of line multiplied by answer to mp2 or answer to mp2 multiplied by 566 or length of line divided by answer to mp2 ; 4 rounds answer to no more than correct decimal places ; [4]

Page 5 Mark Scheme Syllabus Paper Cambridge International AS/A Level – October/November 2014 9700 34 © Cambridge International Examinations 2014 (iii) measures at least 5 folds ; converts to actual length ; [2] (iv) folded leaf retains humidity or cuticle prevents transpiration ; [1] [Total: 20]