Cambridge A Level Biology 9700 — 2005 Oct/Nov Paper 3 · Variant 1

This document consists of 8 printed pages and 4 blank pages. SPA (MML 8289 4/04) S84443/3 © UCLES 2005 [Turn over UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Subsidiary Level and Advanced Level BIOLOGY 9700/03 Paper 3 Practical Test AS October/November 2005 1 hour 15 minutes Candidates answer on the Question Paper. Additional Materials: As listed in Instructions to Supervisors Centre Number Candidate Number Name READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name on all work you hand in. Write in dark blue or black pen in the spaces provided on the Question Paper. You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Answer both 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 45 minutes on Question 1 and 30 minutes on Question 2. For Examiner’s Use 1 2 Total

1 Starch is a storage product found in many plant cells. It contains a carbohydrate called amylose that stains blue / black in the presence of iodine in potassium iodide solution. You are provided with three solutions of the enzyme amylase, of different concentrations, labelled A1, A2 and A3. Do not assume that they are in the correct order of concentration. You are also provided with a suspension of starch. You are required to investigate the effect of the three enzyme concentrations on the starch suspension. Place three rows of five separate drops of iodine solution onto a dry tile. Label the rows A1, A2 and A3, as shown in Fig. 1.1. Fig. 1.1 A1 A2 A3 drops of iodine solution white tile 2 9700/03/O/N/05 For Examiner’s Use © UCLES 2005

(a) (i) Use the prepared tile to investigate the effect of enzyme concentration on the starch suspension. Take no more than ten minutes to complete your investigation. Record your observations in Table 1.1. Table 1.1 [2] (ii) Explain your procedure. … … … … … [3] 3 9700/03/O/N/05 [Turn over For Examiner’s Use © UCLES 2005 amylase concentration A1 A2 A3 observations

(b) A student carried out a similar experiment and obtained the results shown in Table 1.2. Table 1.2 Rate can be calculated by using the formula; 1 rate = ––––––– time/min (i) Complete the table to show the rate for 2.0% amylase concentration. [1] (ii) Use the data in Table 1.2 to plot a graph of amylase concentration against one of the other variables, on the grid below. [4] 4 9700/03/O/N/05 For Examiner’s Use © UCLES 2005 amylase concentration / % 0.5 1.0 1.5 2.0 time taken for complete hydrolysis / min 10 8 5 2 rate of reaction / min–1 0.1 0.125 0.2

(iii) Explain these results. … … … [2] (c) Explain how the experiment could be modified to investigate the effect of temperature on the rate of reaction. … … … … … … [3] [Total: 15] 5 9700/03/O/N/05 [Turn over For Examiner’s Use © UCLES 2005

2 S1 is a slide of mammalian liver. (a) (i) Make a high-power drawing to show a group of four cells. Labels are not required. [4] (ii) The mean width of a liver cell is 30
m Use the eyepiece graticule to determine the mean width of a nucleus. Show your working. mean width of nucleus …
m [3] 6 9700/03/O/N/05 For Examiner’s Use © UCLES 2005 © UCLES 2005

BLANK PAGE QUESTION 2 CONTINUES ON PAGE 8 7 9700/03/O/N/05 [Turn over

(b) Fig. 2.1 is a electronmicrograph of a liver cell. ×10000 Fig. 2.1 8 9700/03/O/N/05 For Examiner’s Use © UCLES 2005

(i) Name four visible structures on the electronmicrograph that cannot be seen on the microscope slide. 1. … 2. … 3. … 4. … [2] (ii) Explain why these structures are visible on the electronmicrograph but not on the microscope slide. … … [1] [Total: 10] 9 9700/03/O/N/05 [Turn over For Examiner’s Use © UCLES 2005

BLANK PAGE 12 9700/03/O/N/05 Copyright Acknowledgements: Fig. 2.1 Taken from http//web.mit.edu/7.19/www/lecture8/JPEGS/Lec8a/P814liver_ep.jpg © Massachusetts Institute of Technology 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 University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS GCE A/AS Level MARK SCHEME for the November 2005 question paper 9700 BIOLOGY 9700/03 Paper 3 maximum raw mark 25 This mark scheme is published as an aid to teachers and students, to indicate the requirements of the examination. It shows the basis on which Examiners were initially instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began. Any substantial changes to the mark scheme that arose from these discussions will be recorded in the published Report on the Examination. All Examiners are instructed that alternative correct answers and unexpected approaches in candidates’ scripts must be given marks that fairly reflect the relevant knowledge and skills demonstrated. Mark schemes must be read in conjunction with the question papers and the Report on the Examination. The minimum marks in these components needed for various grades were previously published with these mark schemes, but are now instead included in the Report on the Examination for this session. • CIE will not enter into discussion or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the November 2005 question papers for most IGCSE and GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.

Page 1 Mark Scheme Syllabus Paper GCE A/AS LEVEL – November 2005 9700 3 © University of Cambridge International Examinations 2005 Qn Expected Answers Marks Additional Guidance 1 (a) (i) A2 faster / less black than A3; A3 faster / less black than A1; 1 1 Order of reactivity A2 A3 A1 Accept reference to colour or endpoint. (ii) Three from Add suspension to each of three test- tubes; Same volumes; (Pipettes drops) every fixed time interval; Until determined end point described; Max 3 (b) (i) 0.5 1 (ii) Amylase conc on X axis and both axes labelled with units correct; scale correct; plots correct; points joined correctly; 1 1 1 1 (iii) More enzyme means more active sites; Qualification of above point; 1 1 (c) Different temperatures; Keep enzyme concentration constant; Same time / time for complete hydrolysis; 1 1 1 15 2 (a) (i) Four from: Quality i.e. clear single unbroken lines; Four cells only; Spaces between cells, at least three touching; Nuclei drawn at least ¼ smallest width; All very irregular shape; Max 4 Accept three cells out of four for each marking point (ii) Evidence of at least three measurements and mean; Correct working; 10 - 15µm; 1 1 1 Correct answer only = 2 (b) (i) Mitochondria; golgi; EPR; ribosomes; glycogen granules; cell membrane; vesicle; nuclear membrane; lysosome; 2 max 4 correct = 2 marks 3 correct = 1 mark (ii) Greater resolution; 1 10 Ignore magnification Total 25

Page 2 Mark Scheme Syllabus Paper GCE A/AS LEVEL – November 2005 9700 3 © University of Cambridge International Examinations 2005