Cambridge IGCSE Twenty-First Century Science 0608 — 2011 Oct/Nov Paper 4 · Variant 1

This document consists of 16 printed pages. DC (SM/DJ) 35670/1 © UCLES 2011 [Turn over UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education * 9 2 4 0 4 4 3 7 7 6 * TWENTY FIRST CENTURY SCIENCE 0608/04 Paper 4 October/November 2011 1 hour 30 minutes Candidates answer on the Question Paper. No Additional Materials are required. 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 or graphs. 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. For Examiner’s Use 1 2 3 4 5 6 7 8 9 Total www.XtremePapers.com

2 0608/04/O/N/11 © UCLES 2011 For Examiner’s Use 1 This question is about generating electricity from biomass (waste vegetable matter). (a) Burning biomass to generate electricity is an example of a renewable energy source. Explain why burning biomass is renewable. … … …[1] (b) The following energy flow diagram shows the energy obtained from burning 25 kg of biomass. The energy is measured in megajoules (MJ). waste heat 60 MJ electrical energy produced heat energy in steam used in factory 200 MJ total energy released by burning 25 kg biomass 400 MJ

3 0608/04/O/N/11 © UCLES 2011 [Turn over For Examiner’s Use (i) Explain how the energy flow diagram shows that 140 MJ of electrical energy were produced. … …[1] (ii) Use the equation efficiency = useful output energy × 100 total input energy % to calculate the efficiency of production of electrical energy. Show your working. efficiency = … % [2] (iii) The manager of the power station claims that the efficiency is not the value calculated in (ii), but is actually 85%. Explain how the figures in the energy flow diagram can support the manager. … … … …[1]

4 0608/04/O/N/11 © UCLES 2011 For Examiner’s Use (c) Some power stations can burn both coal and biomass. The efficiency of these power stations varies from 30% to 60%. The graph shows the relationship between power station efficiency and the amount of carbon dioxide emitted. Two different fuels are shown: • 100% coal • 80% coal, 20% biomass. 350 300 250 200 150 100 30 40 power station efficiency (%) 50 60 Key 100% coal carbon dioxide emission (g/MJ) 80% coal, 20% biomass For both fuels, a more efficient power station emits less carbon dioxide. What else does the graph show? … … … … …[2] [Total: 7]

5 0608/04/O/N/11 © UCLES 2011 [Turn over For Examiner’s Use 2 This question is about microwave radiation. (a) The table shows the electromagnetic spectrum. (i) Fill in the missing names. radio waves … … visible light … … gamma rays [2] (ii) In the table, put a tick (✓) next the name of each ionising radiation. [1] (b) Some people will not let their children have mobile phones. These people believe that microwaves from mobile phones may be a health risk. Explain clearly what the precautionary principle is, and how these people are applying it. … … … …[2] (c) Microwave ovens are much more powerful than mobile phones, but they are not thought to be dangerous. Explain how the construction of microwave ovens protects users from microwave radiation. … …[1] [Total: 6]

6 0608/04/O/N/11 © UCLES 2011 For Examiner’s Use 3 This question is about the movement of the Earth’s tectonic plates. (a) Although Wegener’s idea of continental drift was first suggested in 1912, it was more than 50 years before geologists believed that the Earth’s crust is moving. Suggest two reasons for this. … … … …[1] (b) In the 1960s, measurements of magnetism in the seafloor produced evidence to support the idea of continental drift. Describe what was discovered, and explain how it supported the idea that continents could move. … … … …[2]

7 0608/04/O/N/11 © UCLES 2011 [Turn over For Examiner’s Use (c) The Earth’s tectonic plates in the Indian Ocean region are shown in the diagram. The pairs of arrows A, B, C, D, E and F show the directions of movement of the plates. A B C D E F Key land sea (i) Which of the movements A, B, C, D, E and F are building mountains? Write down each of the letters. …[1] (ii) Which of the movements A, B, C, D, E and F are causing seafloor spreading? Write down each of the letters. …[1] (iii) Explain how earthquakes are caused. … … … …[2] [Total: 7]

8 0608/04/O/N/11 © UCLES 2011 For Examiner’s Use 4 Country A is an industrialised country. Farmers in country A use synthetic pesticides to prevent insect pests attacking their crops. They spread synthetic fertilisers on their fields. Country B is a developing country. Farmers in country B use organic farming methods. They do not use synthetic pesticides or synthetic fertilisers. (a) (i) Describe one method that farmers in country B may use to protect their crops from insect pests. … …[1] (ii) How may farmers in country B be affected by the fact that they do not use pesticides? … …[1] (b) Pesticide residues on food can be harmful to people. Pesticides can cause environmental damage. Suggest why, despite the problems associated with the use of pesticides, farmers in country A use them. Use ideas of risk and benefit in your answer. … … … …[2] [Total: 4]

9 0608/04/O/N/11 © UCLES 2011 [Turn over For Examiner’s Use 5 Methane is a fuel. It is burned to release heat energy. Look at the formula and diagram of a molecule of methane. CH4 In a plentiful supply of oxygen, O2, methane burns to produce carbon dioxide, CO2, and water, H2O, only. (a) Complete this table to show the number of atoms of each element in the reactants and products when one molecule of methane burns. carbon hydrogen oxygen number of atoms in reactants 1 number of atoms in products 1 [1] (b) Complete this table to show the number of molecules in the reactants and products when one molecule of methane burns. reactants products methane oxygen carbon dioxide water number of molecules 1 [3] (c) When methane burns in a limited supply of air, other products are also formed. These other products cause air pollution. Name one of these other products. …[1] [Total: 5]

10 0608/04/O/N/11 © UCLES 2011 For Examiner’s Use 6 Most window frames are made from either wood or unplasticised polyvinylchloride (uPVC). Data from a Life Cycle Assessment (LCA) for window frames, of the same size, made from each of these two materials are shown in the table. part of LCA wood uPVC energy for production, use and disposal 9150 MJ 9713 MJ fossil fuel used 5.57 kg 18.23 kg carbon dioxide produced 457 kg 487 kg smog chemicals 893 383 air acidification 29.6 37.7 water pollution 67 1.6 (a) For which parts of the LCA is wood a more sustainable material for a window frame than uPVC? Choose your answers by ticking the correct boxes. tick (✓) energy for production, use and disposal fossil fuel used carbon dioxide produced smog chemicals air acidification water pollution [3] (b) Wooden window frames require frequent painting, but uPVC window frames are coloured during manufacture and never need to be painted. Describe and explain the effect this has on a comparison of the LCA for these two types of window frame. … … …[2]

11 0608/04/O/N/11 © UCLES 2011 [Turn over For Examiner’s Use (c) The melting point of polymers can be increased by increasing their chain length. Explain how longer chains give a polymer a higher melting point. … … …[2] (d) The main cause of air acidification is the release of sulfur dioxide from burning fossil fuels. Acid rain is formed from sulfur dioxide in the air. (i) Write a symbol equation for the burning of sulfur to produce sulfur dioxide. …[1] (ii) Explain how acid rain is formed from sulfur dioxide. … … …[2] (iii) Describe one environmental problem caused by acid rain. … …[1] [Total: 11]

12 0608/04/O/N/11 © UCLES 2011 For Examiner’s Use 7 Janet is feeling unwell and goes to the doctor. The doctor says that Janet is suffering from influenza. Janet asks the doctor to give her antibiotics. The doctor says that antibiotics will not help Janet to feel better. (a) Explain why antibiotics will not help Janet to feel better. … … …[2] (b) John does not want to catch influenza. He goes to the doctor for a vaccination to help prevent him catching this disease. John had an influenza vaccination last year. (i) Explain why John needs to have a vaccination against influenza this year, even though he had one last year. … …[1] (ii) Describe how vaccinations provide protection from the microorganisms that cause diseases. … … …[2] (c) In 2009, there was an outbreak of influenza caused by a new microorganism called H1N1. This new type of influenza spread quickly around the world. Scientists developed a vaccine against H1N1 to help stop the spread of the disease. Abi is pregnant. Her doctor recommends that she should have the vaccination against H1N1. Abi is not sure whether she should have the vaccination or not. She talks to her friends and asks their opinions.

13 0608/04/O/N/11 © UCLES 2011 [Turn over For Examiner’s Use The vaccine has been developed very quickly and has not been tested as thoroughly as other vaccines. When you are pregnant, your immune system is weakened and you are not able to fight off infections as easily. The vaccination protects against H1N1 and does not cause any damage to the baby. It is important for a pregnant woman to make the right decision for both her and her baby. Having the vaccination really hurts and your arm can be very sore for a few days afterwards. A B D E C Complete the table by writing the letters A, B, C, D and E in the correct columns. Each letter can be used once only. friends who give reasons to have the vaccination friends who give reasons not to have the vaccination friends whose comments do not support either argument [2] [Total: 7]

14 0608/04/O/N/11 © UCLES 2011 For Examiner’s Use 8 (a) What are embryonic stem cells? … …[1] (b) Embryos can be cloned to produce large numbers of stem cells. (i) Suggest one reason why some people believe these embryos should be cloned. … …[1] (ii) Suggest one reason why some people believe it is wrong to clone embryos. … …[1] (c) Read the sentences in the box. A Scientists have discovered that baby teeth are a source of stem cells. B Storing your children’s baby teeth could help to save their lives in the future. C The stem cells are easy and painless to extract. D Storing the teeth is very expensive. E There is no guarantee stem cells will be able to help cure diseases. F Many teeth can be stored for each child. G It may not be possible to extract the stem cells if the teeth are damaged. Which of the sentences, A, B, C, D, E, F and G, suggest reasons why (i) parents may choose to store their children’s baby teeth … [1] (ii) parents may choose not to store their children’s baby teeth. … [1]

15 0608/04/O/N/11 © UCLES 2011 [Turn over For Examiner’s Use (d) It is also possible for clones of whole animals to occur. Describe, in terms of the cells involved, one natural and one artificial way in which clones of whole animals can occur. natural: … … artificial: … …[3] [Total: 8]

16 0608/04/O/N/11 © UCLES 2011 For Examiner’s Use 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. 9 Multi-cellular organisms have evolved to have nervous and hormonal communication systems. These are involved in homeostasis. (a) What is meant by the term homeostasis ? … …[1] (b) Look at the flow diagram. This shows an example of nervous communication. hot object A B C D E skin brain and spinal cord muscles hand pulled away Which one of the boxes, A, B, C, D or E, represents: (i) the effector cells, … [1] (ii) the sensor (receptor) cells? … [1] (c) Communication can be hormonal as well as nervous. Give one example of hormonal communication and describe two differences between hormonal and nervous communication. … … … …[2] [Total: 5]

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education MARK SCHEME for the October/November 2011 question paper for the guidance of teachers 0608 TWENTY FIRST CENTURY SCIENCE 0608/04 Paper 4 (Extended Written), maximum raw mark 60 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. • Cambridge will not enter into discussions or correspondence in connection with these mark schemes. Cambridge is publishing the mark schemes for the October/November 2011 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses. www.XtremePapers.com

Page 2 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0608 04 © University of Cambridge International Examinations 2011 1 (a) biomass grows at same rate as burning to replace that burnt [1] allow implication that it grows faster, but not slower, than it is burnt (b) (i) 400 – 60 – 200 (MJ) = 140 (MJ) [1] any clear indication of process e.g. ‘It’s the input take away the steam and the waste’ (ii) 140 × 100/400 (1) = 35% (1) [2] full marks for correct answer without working (iii) useful output is actually 200 + 140 MJ and 340 × 100%/400 = 85% [1] need not evaluate the calculation but needs to say what it is (c) for same efficiency, biomass emits less CO2 than coal (1); more efficient power stations have reduced CO2 emissions and this difference is less significant at higher efficiencies/new power stations than at lower efficiencies/older power stations (1) [2] first mark is for relating the relative positions of the two lines second mark is for noting the downward trend and the fact that it is non-linear Total [7] 2 (a) (i) microwave, infrared, ultraviolet, X-rays in that order [2] all correct = 2 2 or 3 correct = 1 (ii) ticks in at least two of the three right-hand end boxes [1] any two of these and no tick for a non-ionising radiation for the mark. accept any clear indication of choices (b) explaining precautionary principle – probability unknown but consequence could be serious (1); should not take any risk with children, no matter how remote the risk may be (1) [2] accept ‘better safe than sorry’ accept any reason based on children’s possible susceptibility, e.g. thin skulls, rapidly developing brains (c) metal walls/door screen reflect microwaves back into cavity [1] both metal and reflect (or block) needed Total [6]

Page 3 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0608 04 © University of Cambridge International Examinations 2011 3 (a) no detectable movement (1); previous (static) theories worked well (1); reluctant to change their ideas (1); suspicious of Wegener as an outsider (1) [1] any two separate reasons for the mark (b) magnetic patterns (stripes) on seafloor) (1); symmetrical about mid-ocean ridge (1); evidence of seafloor spreading (1); provides mechanism for drift (1) [2] any two (c) (i) A and E [1] need both and no others (ii) B, C and F [1] any two: must include F and exclude A, E and D (iii) adjacent/touching plates push against each other (sideways) (1); stresses build up (1); plates suddenly slip (1) [2] any two Total [7] 4 (a) (i) pick off by hand/crop rotation/natural predators [1] (ii) reduced yield [1] (b) balance of risk and benefit (1); residues are very small/pose little risk but increase in yield is high (1) [2] Total [4] 5 (a) 4 4 4 4 [1] all correct for one mark (b) (1) 2 1 2 [3] one mark for each correct number (c) carbon/carbon monoxide [1] Total [5]

Page 4 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0608 04 © University of Cambridge International Examinations 2011 6 (a) ticks in boxes 1, 2, 3 and 5 [3] all 4 correct boxes ticked = 3 marks 3 boxes = two marks 2 boxes = one mark 5 boxes ticked max 1 all 6 boxes ticked = 0 (b) more energy used to produce paint (1); more environmental pollution caused by production of paint (1) [2] (c) longer chains have more contact with each other (1); forces of attraction between longer chains are higher (1); more energy is needed to pull longer chains apart (1) [2] any two (d) (i) S + O2
SO2 [1] (ii) reacts with oxygen in the air (1); reacts with water in the air (1) [2] (iii) corrodes statues etc./acidifies lakes/kills fish/kills trees [1] Total [11] 7 (a) ’flu caused by a virus (1); antibiotics only effective against bacteria (or fungi) (1) [2] (b) (i) ’flu virus changes/mutates very quickly [1] (ii) cause body to produce antibodies (1); before infection (1) [2] (c) BC AE D [2] all 5 correct = 2 3 or 4 correct = 1 Total [7]

Page 5 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2011 0608 04 © University of Cambridge International Examinations 2011 8 (a) unspecialised cells that can develop into any type of cell [1] (b) (i) (stem cells) can be used to: cure/treat diseases which will save lots of lives [1] (ii) unnatural/‘playing God’ idea [1] (c) (i) B C F [1] (ii) D E G [1] (d) natural identical twins (1); when cells of embryo separate (1); artificial when nucleus from adult body cell (1); transferred to empty unfertilised egg cell (1) [3] any 3 points Total [8] 9 (a) maintaining a constant internal environment [1] (b) (i) D [1] (ii) B [1] (c) correct example plus any two of: slower (1); travel in the blood (1); longer-lasting (1); has target organ (1) [2] no marks for example alone example plus one factor gains 1 mark Total [5]