Cambridge A Level Biology 9700 — 2010 May/June Paper 3 · Variant 3

This document consists of 11 printed pages and 1 blank page. DC (CW/DJ) 15995/7 © UCLES 2010 [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 pen. You may use a pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. 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. You are advised to spend one hour on each question. * 4 9 7 5 5 9 7 2 3 1 * BIOLOGY 9700/33 Paper 31 Advanced Practical Skills May/June 2010 2 hours Candidates answer on the Question Paper. Additional Materials: As listed in the Confidential Instructions For Examiner’s Use 1 2 Total

2 9700/33/M/J/10 © UCLES 2010 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 each question and 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 required to investigate how much glucose diffuses through selectively permeable Visking (dialysis) tubing in 15 minutes. You are provided with • 25 cm3 of 10% glucose solution, labelled G • about 20 cm of Visking (dialysis) tubing in a container of distilled water, labelled V • 100 cm3 of distilled water, labelled W • 20 cm3 of 0.1 % glucose solution, labelled S1 • 20 cm3 of 0.2 % glucose solution, labelled S2 • 20 cm3 of 0.3 % glucose solution, labelled S3 • 100 cm3 of Benedict’s solution, labelled Benedict’s solution. 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. Use a syringe to put 10 cm3 of G 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 large test-tube in a test-tube rack. 6. Fold the open end of the Visking tubing over the top of the large test-tube as shown in Fig. 1.1. 7. Use an elastic band to hold the Visking tubing in place. 8. Use a syringe to put some of W into the large test-tube so that it surrounds the Visking tubing. 9. Immediately start a stop clock, stop watch or record the time on a clock to time for 15 minutes.

3 9700/33/M/J/10 © UCLES 2010 [Turn over For Examiner’s Use (a) Draw on Fig. 1.1 a line to show the level of water in the large test-tube. [1] elastic band Visking tubing large test-tube glucose solution Fig. 1.1 To find out how much glucose has diffused out of the Visking tubing after 15 minutes, you are provided with solutions S1, S2 and S3. In order to find how much glucose has diffused from inside the Visking tubing into the water you will need to test a sample of the water with Benedict’s solution. You should record the time taken for the first appearance of any green colour. The result will be compared with the time taken for the first appearance of any green colour obtained from testing solutions S1, S2 and S3 with Benedict’s solution. To do this you need to use the same procedure. (b) State the volume of Benedict’s solution and the volume of the solutions (S1, S2 and S3) and the sample you are testing. volume of Benedict’s solution … cm3 volume of each solution (S1, S2 or S3) … cm3 volume of sample … cm3 [1] (c) State one variable, other than volume, which needs to be kept constant when you do the tests and describe how you will keep this variable constant. … … …[2] 10. After 15 minutes, pour the water from around the Visking tubing into a beaker or container and label it sample. 11. Now test all four solutions, sample, S1, S2 and S3.

4 9700/33/M/J/10 © UCLES 2010 For Examiner’s Use (d) (i) Prepare the space below and record your results. [4] (ii) Estimate the concentration of glucose in the sample. …[1]

5 9700/33/M/J/10 © UCLES 2010 [Turn over For Examiner’s Use (iii) Suggest how you might modify this investigation to find the effect of temperature on the rate of diffusion of glucose through Visking tubing. … … … … … …[2] (e) A student investigated the rate of diffusion of a coloured solution through agar. A Petri dish containing a layer of agar had a small well of 1 cm diameter, cut so that 10 drops of the coloured solution could be placed in the well. The distance the coloured solution diffused from the edge of the well was measured at 15 minute intervals. Fig. 1.2 shows the surface view of the Petri dish after 75 minutes. well with coloured solution (1 cm diameter) Petri dish agar 29 mm distance diffused by coloured solution after 75 minutes (29 mm) Fig. 1.2

6 9700/33/M/J/10 © UCLES 2010 For Examiner’s Use The results of the student’s investigation are shown in Table 1.1. Table 1.1 time / min distance diffused from well by coloured solution / mm 0 0 15 14 30 22 45 26 60 28 75 29 (i) Plot a graph to show the results in Table 1.1. [4]

7 9700/33/M/J/10 © UCLES 2010 [Turn over For Examiner’s Use (ii) Use the graph to calculate the rate of diffusion of the solution between 10 minutes and 20 minutes. Show on your graph where you took the readings. [1] Show all the steps in your calculation. [1] [2] (iii) Describe and explain the trend in the rate of diffusion shown in the graph you have drawn in (e)(i). … … … … …[2] (f) The ruler used to measure the distances in Table 1.1 is shown in Fig. 1.3. 0 1 cm magnification x 3 Fig. 1.3 State the uncertainty of the measurements using this ruler. …[1] [Total: 22]

8 9700/33/M/J/10 © UCLES 2010 For Examiner’s Use 2 Fig. 2.1 and Fig. 2.2 are photomicrographs of blood taken from two different types of organisms. magnification × 2500 Fig. 2.1 X magnification × 700 Fig. 2.2

9 9700/33/M/J/10 © UCLES 2010 [Turn over For Examiner’s Use (a) (i) Make large, labelled drawings of two different types of cell from Fig. 2.1 and one cell from Fig. 2.2. Indicate on the photomicrographs the cells that you have drawn. [4] (ii) Prepare the space below so that it is suitable for you to compare and contrast the cells in Fig. 2.1 and Fig. 2.2. Record your observations in the space which you have prepared. [5]

10 9700/33/M/J/10 © UCLES 2010 For Examiner’s Use (iii) Calculate the actual diameter of the cell shown by the line X in Fig. 2.2. Show all the steps in your calculation. …μm [2] (iv) Suggest how you would obtain a mean diameter for cells of this type. … … …[1]

11 9700/33/M/J/10 © UCLES 2010 For Examiner’s Use K1 is a slide showing transverse sections through blood vessels. (b) (i) Draw a large plan diagram of two different blood vessels shown in K1. [5] (ii) Suggest one way in which these blood vessels are adapted for transport. …[1] [Total: 18]

12 9700/33/M/J/10 © UCLES 2010 BLANK PAGE Copyright Acknowledgements: Fig. 2.1 REVY, ISM/SCIENCE PHOTO LIBRARY Fig. 2.2 Edward Kinsman/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.

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS GCE Advanced Subsidiary Level and GCE Advanced Level MARK SCHEME for the May/June 2010 question paper for the guidance of teachers 9700 BIOLOGY 9700/33 Paper 31 (Advanced Practical Skills 1), 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 must be read in conjunction with the question papers and the report on the examination. • CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the May/June 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.

Page 2 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 33 © UCLES 2010 Question Expected Answers Additional Guidance Marks 1 (a) Draw on Fig. 1.1 a line to show the level of water in the large test-tube. MMO decision 1 line drawn above or at the same level as the line showing the contents in the Visking tubing; [1] (b) State the volume of Benedict’s solution and the volume of the solutions and the sample. MMO decision 1 (volume of Benedict’s) equal to or greater than (volume of each solution and sample) AND (volume of each solution and sample) equal; Reject any other values e.g. 2.5 cm3 [1] (c) State ONE variable, other than volume, which needs to be kept constant when you do the TESTS and describe how you will keep this variable constant. temperature; Reject if in context of Visking tubing set up or experiment e.g. keep at room temperature Reject if more than one variable given [1] MMO decisions 2 use of water-bath AND between 80oC and 100oC or boiling; [1]

Page 3 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 33 © UCLES 2010 Question Expected Answers Additional Guidance Marks (d) (i) Prepare the space below and record your results. 1. table with all cells drawn No outer boundary needed (heading to left/ top) AND a heading to describe (sample, or solution or test- tube or glucose); [1] PDO recording 2 2. (heading) time (/) s or sec(onds) or min(utes); Reject if units in table [1] MMO collection 2 3. time for 0.3%/S3 quicker than 0.2%/S2; Must be clear units Reject 1.24 [1] 4. figures for 0.2%/S2 quicker than 0.1%/S1; [1] (ii) Estimate the concentration of glucose in the sample. ACE interpretation 1 correct estimate from their results Reject if sample not recorded in results AND percentage/%; • is 0.1% or 0.2% or 0.3% • between 0.1% and 0.2% • 0.15% • between 0.2% and 0.3% • 0.25% • greater/more than 0.3% • less than 0.1% Reject any other values Ignore use of S1,S2, S3 [1]

Page 4 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 33 © UCLES 2010 Question Expected Answers Additional Guidance Marks (iii) Suggest how you might modify this investigation to find the effect of temperature on the rate of diffusion of glucose through Visking tubing. ACE improvements 2 states 5 or more temperatures OR gives examples of 5 or more 1oC to 100oC; [1] (in context of readings) repeats or more than once or replicates AND mean or average OR take samples at same time interval or example of time with units OR same volumes or example of volume with units of samples removed OR rate calculated from time taken to change colour OR same concentration or volume of glucose or example of concentration or volume + units; Reject if change another variable e.g. concentration of glucose Reject amount [1]

Page 5 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 33 © UCLES 2010 Question Expected Answers Additional Guidance Marks (e) (i) Plot a graph to show the results in Table 1.1. O x-axis time (/) min(ute)s y-axis AND distance (diffused from well by coloured solution /) mm; [1] S scale as 20 min to 2 cm ECF if no labels on axes for O Allow 5/10 at origin but must label origin AND 5 mm to 2 cm; Allow 5/10 as long as scale 5 mm to 2 cm but must label origin Reject if awkward scale [1] P correct plotting using crosses or dots in circle only; Intersection of cross must be clear to show plot Reject plotting if scale is awkward Reject if only blobs/dots/blobs in circles [1] PDO layout 4 0 0 15 14 30 22 45 26 60 28 75 29 L line joined point to point or smooth curve; Quality – no thicker than on grid, not feathery for the complete line Joining plots – • Ruled lines plot to plot • Curve through all plots Extrapolation • Not beyond x- or y-axis Reject if no 0,0 plot [1]

Page 6 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 33 © UCLES 2010 Question Expected Answers Additional Guidance Marks (ii) Use the graph to calculate the rate of diffusion of the solution between 10 mins and 20 mins. Show on your graph. MMO collection 1 1. shows on graph at least one reading(s) between or at 10 and 20 minutes; [1] PDO display 1 2. shows distance divided by time (has to be clear) any number between 4 and 20 divided by or / or ÷ whole number (between 4 and 20) or shows subtraction of numbers; Reject if not clear distance divided by time [1] ACE interpretation 1 3. correct answer AND mm min-1 or mm per min or mm/min; [1] PDO display 1 4. any figure rounded to maximum of four significant figures; [1] (iii) Describe and explain the trend in the rate of diffusion shown in the graph you have drawn in (e) (i). (description) rate or distance decreases or slows or levels off; [1] ACE conclusion 2 (in correct context of diffusion ref. to) Idea of concentration or diffusion gradient, getting less OR Idea of (high at beginning) concentration or diffusion gradient high OR Idea of (at end) evenly coloured; [1]

Page 7 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 33 © UCLES 2010 Question Expected Answers Additional Guidance Marks (f) State the uncertainty of the measurements using this ruler. ACE interpretation 1 +/- 0.5 mm OR +/- 0.05 cm; [1] Total [22]

Page 8 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 33 © UCLES 2010 Question Expected Answers Additional Guidance Marks 2 (a) (i) Make a large, labelled drawings of two different types of cell from Fig. 2.1 and one cell from Fig. 2.2. Indicate on the photomicrographs the cells that you have drawn. 1. (only cells marked on Figs. and drawn) MMO collection 1 on Fig. 2.1 white blood cell AND any one complete red blood cell on Fig. 2.2 AND any one complete red blood cell; Reject if shown more cells Reject if drawing overlaps text of question [1] PDO layout 1 2. clear, sharp, (not thicker than grid line for whole line) unbroken lines Allow 1 error in three cells 0 error for two or one cell AND no shading AND smallest cell drawn larger than 2 cm (+/- 1mm) at widest point; Must draw at least TWO cells [1] 3. (wbc from Fig. 2.1) (nucleus position) nearer to one side (nucleus size) AND (+ or – 1 mm) nucleus fills between 50 and 75 % of whole cell; Reject if any additional organelles drawn in any cell [1] MMO decision 2 4. Reject if any label is biologically incorrect e.g. cell wall any ref. to plants e.g. cell wall or named plant cell or named animal cell other than blood cells. Ignore nucleolus and named blood cells One correct label with label line from nucleus nucleoplasm cytoplasm cell membrane/AW; Reject if any writing on drawing [1]

Page 9 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 33 © UCLES 2010 Question Expected Answers Additional Guidance Marks (ii) Prepare the space below so that it is suitable for you to compare and contrast the cells in Fig. 2.1 and Fig. 2.2. (organise) table/ venn diagram/ ruled connected boxes (heading for differences) Fig. 2.1 and Fig. 2.2, labelled cells from (a) (i), named cells linked to figs. all differences statements opposite each other; Fig 2.1 Fig. 2.2 [1] PDO recording 2 heading similarities; [1] ACE interpretation 3 Mark with identification from (i) drawings even if incorrectly named cells Mark for any similarities or differences max 3 Must be clear which cells are being compared or contrasted Ticks and crosses requires a key (continued on next page)

Page 10 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 33 © UCLES 2010 Question Expected Answers Additional Guidance Marks feature Fig. 2.1 Fig. 2.2 Only credit each number once. rbc or label from (i) wbc or label from (i) rbc or label (rbc) small(er) (wbc) larg(er) 1. size cells; small(er) larg(er) rbc or label and wbc or label and only rbc/label wbc present no wbc 2. types of cells; two one many or more cells/rbcs few(er) cells/rbcs many or more rbcs one or a Reject few/small no. 3. number OR degree of packing; dens(er)/more overlapping rbcs less dense; absent Allow cannot be seen present absent Allow cannot be seen present (no key) present present 4. nucleus OR nucleus shape; lobed or irregular not lobed or oval or round or regular or smooth circular or round irregular circular or round oval 5. cell shape; irregular oval Allow few or some round Reject round not granular granular 6. cytoplasm; granular not granular or normal 7. cytoplasm OR cell membrane; (no key) present Beware Fig 2.1 cells magnified 3+ more than Fig 2.2 so cells in Fig 2.1 smaller Reject nucleus Reject if just cells have nucleus present or absent Reject 3D , rugby or disc or spherical or biconcave or arbitrary or random Reject negatives e.g. not circular Reject opposites e.g. regular [max 3]

Page 11 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 33 © UCLES 2010 Question Expected Answers Additional Guidance Marks (iii) Calculate the actual diameter of the cell shown by the line X in Fig. 2.2. measures line X correctly in mm or cm; Reject m mm cm 26(.0) 2.6 26.5 2.65 27(.0) 2.7 27.5 2.75 28(.0) 2.8 [1] MMO collection 2 shows (their measurement divided by or / or ÷ 700) AND × 1000 or 103 (mm) or 10000 or 104 (cm) or × 10 × 1000; Reject use or conversion to metres Reject if no units [1] (iv) Suggest how you would obtain a mean diameter for cells of this type. ACE improvement 1 idea of make more measurements Reject calculate AND add together AND divide by the number of measurements; [1]

Page 12 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 33 © UCLES 2010 Question Expected Answers Additional Guidance Marks (b) (i) Draw a large plan diagram of two different blood vessels shown in K1. Reject if one line for each vessel. PDO layout 1 1. clear, sharp, (unbroken lines) complete vessels only AND no shading AND large; Reject if overlaps text of question [1] 2. no cells AND only two complete vessels drawn; Minimum of three lines between two vessels [1] MMO collection 2 3. different vessels; (more than one) at least two complete vessels OR total size or shape; Minimum of three lines between two vessels [1] 4. at least one complete vessel drawn with two or more layers; Minimum three lines [1] MMO decision 2 5. one with wall thicker than other vessel wall; Reject if more than two vessels [1]

Page 13 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 33 © UCLES 2010 Question Expected Answers Additional Guidance Marks (ii) Suggest one way in which these blood vessels are adapted for transport. ACE conclusion 1 lumen/hollow OR smooth muscle OR tunica media OR elastic fibres/elastin OR collagen OR tunica externa; Reject if more than one given [1] Total [18]