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Centre No. Surname Paper Reference 6 1 3 4 Candidate No. 0 1 Initial(s) Signature Paper Reference(s) 6134/01 Examiner’s use only Edexcel GCE Team Leader’s use only Biology (Salters-Nuffield) (Pilot) Advanced Unit Test 4 Question Leave Number Blank Tuesday 20 June 2006 – Morning Time: 1 hour 15 minutes 1 2 3 4 5 Materials required for examination Ruler Calculator Items included with question papers Nil 6 Instructions to Candidates In the boxes above, write your centre number, candidate number, your surname, initial(s) and signature. The paper reference is shown above. Check that you have the correct question paper. Answer ALL SIX questions in the spaces provided in this booklet. If you need to use additional answer sheets, attach them loosely but securely inside this booklet. Show all the steps in any calculations and state the units. Calculators may be used. Include diagrams in your answers where these are helpful. Information for Candidates The marks for individual questions and parts of questions are shown in round brackets: e.g. (2). The total mark for this question paper is 60. Advice to Candidates You will be assessed on your ability to organise and present information, ideas, descriptions and arguments clearly and logically, taking into account your use of grammar, punctuation and spelling. Total This publication may be reproduced only in accordance with Edexcel Limited copyright policy. ©2006 Edexcel Limited. Printer’s Log. No. N22422A W850/R6134/57570 7/7/4/1100 Turn over *N22422A0116* BLANK PAGE 2 *N22422A0216* Leave blank Answer ALL questions in the spaces provided 1. Give the meaning of the following biological terms: (a) allele ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (2) (b) climax community ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (2) (c) abundance ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (2) Q1 (Total 6 marks) *N22422A0316* 3 Turn over Leave blank 2. The diagram below shows energy flow measured during a study of a grassland ecosystem. The values shown are kJ m–2 year–1 × 104. Values of energy lost through respiration (R) and other means (L) are shown for some organisms. The biomass of the organisms in the ecosystem remained unchanged during the study. R= 2 6 Seed eating birds L=3.7 R=3600 Grasses 44.4 R=12.5 0.07 Spiders L=25.4 1980 Other organisms Grasshoppers 11.6 Field mice (a) Name one primary consumer and one secondary consumer shown in this diagram. Primary consumer ......................................................................................................... Secondary consumer ..................................................................................................... (2) (b) (i) Calculate the gross primary productivity (GPP) for the grasses in this system. Show your working. .................................... kJ m–2 year–1 × 104 (2) (ii) Describe how this figure could be used to calculate the net primary productivity (NPP) of the grasses. ................................................................................................................................ ................................................................................................................................ (1) 4 *N22422A0416* Leave blank (c) (i) Calculate the percentage of the energy taken in by the grasshoppers that is converted into new grasshopper biomass. Show your working. Answer .............................................. (3) (ii) Give two ways in which energy is lost by the grasshoppers other than in respiration. ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ (2) (d) Use your calculated figures from parts (b)(i) and (c)(i) to explain why food chains are of limited length. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (2) Q2 (Total 12 marks) *N22422A0516* 5 Turn over Leave blank 3. The graphs below show changes in the quantities of an antibiotic used in a hospital and the percentage of infections caused by bacteria resistant to the antibiotic over the same time period. 14 Antibiotic used / 12 kg 10 8 6 4 2 0 87 88 89 90 91 92 93 94 Year 14 Resistance / 12 % 10 8 6 4 2 0 87 88 89 90 91 92 93 94 Year (a) Explain how bacteria become resistant to antibiotics. Use the information in the graphs to support your answer. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (6) 6 *N22422A0616* Leave blank (b) Bacteria were grown on an agar plate and incubated with four different antibiotics. The antibiotics were placed on paper discs. The resulting plate is shown in the diagram below. A B C D Paper with antibiotic Areas with no bacteria (i) Give one piece of evidence that suggests that antibiotic B is more effective at killing these bacteria than antibiotic C. ................................................................................................................................ ................................................................................................................................ (1) (ii) Antibiotic C is a much larger molecule than antibiotic B. Explain why this method might not be appropriate when comparing the effectiveness of antibiotics B and C. ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ (2) (iii) Antibiotic C acts by inhibiting the growth of bacterial cell walls. Antibiotic D acts by interfering with the activity of bacterial ribosomes. Use this information to explain why neither antibiotic would be effective against viruses. ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ (2) Q3 (Total 11 marks) *N22422A0716* 7 Turn over Leave blank 4. Tuberculosis (TB) is an infection of the lungs caused by the bacterium Mycobacterium tuberculosis. TB can often be overcome by the immune system. Macrophages destroy the bacteria by phagocytosis. (a) Explain how phagocytosis destroys bacteria. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (2) (b) An investigation into infection with TB was carried out on mice with very few T helper cells (CD4 depleted mice). The mice were infected with M. tuberculosis. Some of the mice were injected with T helper cells taken from mice that were immune to TB. The diagram below summarises the experiment. Result CD4 depleted mouse CD4 depleted mouse T helper cells injected TB develops No TB develops Using the information above, explain: (i) the role of T helper cells in the immune response. ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ (3) 8 *N22422A0816* Leave blank (ii) the effects of HIV infection on the ability of humans to combat TB. ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ (2) (c) In a separate investigation, T helper cells infected with HIV were exposed to fluid from the lung of a TB patient. This fluid contained chemicals secreted by macrophages, which activate T helper cells. The results are shown in the table below. Fluid taken from Rate of HIV production Healthy lung No change TB infected lung Increased Explain the results shown in the table above. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (2) (d) Many people are now infected by both M. tuberculosis and HIV (co-infection). Use the results of both studies above to suggest the effect of co-infection on the rate at which each disease develops. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (3) Q4 (Total 12 marks) *N22422A0916* 9 Turn over Leave blank 5. Following the introduction of DNA fingerprinting into forensic testing, many people have been freed from prison as a result of new evidence provided by the technique. (a) Give reasons why confidence in the new evidence was strong enough to enable the release of these prisoners. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (2) (b) Give one example of physical evidence that could be retained from the original investigation and explain why the sample is suitable for a DNA test to be carried out. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (2) (c) Explain how the results of DNA fingerprinting could be used to find the identity of a dead person. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (3) 10 *N22422A01016* Leave blank (d) Give two other ways in which the identity of a dead person could be determined. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (2) Q5 (Total 9 marks) *N22422A01116* 11 Turn over Leave blank 6. A study of mammals in West Africa has found that populations have decreased by up to 76% in 41 different species. Some species have become extinct in the area, reducing the biodiversity. Source: www.news.bbc.co.uk (a) Explain why extinction of species reduces biodiversity. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (2) (b) It is thought that this loss of biodiversity is an indirect result of European legislation which limits fishing in European waters. Rather than lose their way of life, European fishermen now fish off the West African coast, and this has reduced fish stocks dramatically. The highest density of human populations in West Africa is along the coast. (i) Suggest one reason why fish stocks are important for the human population in West Africa. ................................................................................................................................ (1) (ii) Suggest reasons why changes in European legislation have had an effect on the wild mammal populations of West Africa. ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ (2) 12 *N22422A01216* Leave blank (c) With reference to the information given, describe the importance of considering cultural issues when using legislation for conservation of organisms. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (2) (d) Explain why local legislation is likely to be less effective than international agreements for major conservation projects. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (3) Q6 (Total 10 marks) TOTAL FOR PAPER: 60 MARKS END *N22422A01316* 13 BLANK PAGE 14 *N22422A01416* BLANK PAGE *N22422A01516* 15 BLANK PAGE 16 *N22422A01616*