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GCE MAY 2008 : (A2 1) Co-ordination, Biochemistry and Environment

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Centre Number 71 Candidate Number ADVANCED General Certificate of Education 2008 assessing Module 4: Co-ordination, Biochemistry and Environment A2B11 Biology Assessment Unit A2 1 [A2B11] TUESDAY 13 MAY, AFTERNOON TIME 1 hour 30 minutes. INSTRUCTIONS TO CANDIDATES Write your Centre Number and Candidate Number in the spaces provided at the top of this page. Write your answers in the spaces provided in this question paper. Answer all eight questions. You are provided with Photograph 4.7 for use with Question 7 in this paper. Do not write your answers on this photograph. For Examiner s use only Question Number 1 INFORMATION FOR CANDIDATES The total mark for this paper is 75. Section A carries 60 marks. Section B carries 15 marks. You should spend approximately 20 minutes on Section B. You are expected to answer Section B in continuous prose. Quality of written communication will be assessed in Section B. Figures in brackets printed down the right-hand side of pages indicate the marks awarded to each question or part question. 2 3 4 5 6 7 8 Total Marks A2B1S8 3643 Marks BLANK PAGE A2B1S8 3643 2 [Turn over Section A Examiner Only Marks 1 Remark Describe the cause and the resultant effect of the following types of pollution. Acid rain Cause _____________________________________________________ ___________________________________________________________ Effect _____________________________________________________ ___________________________________________________________ Eutrophication Cause _____________________________________________________ ___________________________________________________________ Effect _____________________________________________________ ________________________________________________________ [4] A2B1S8 3643 3 [Turn over 2 The diagram below represents the nitrogen cycle. Use the diagram to help you answer the questions that follow. atmospheric nitrogen Examiner Only Marks Remark nitrogenfixing bacteria lightning nitrogen fixation A ammonium in soil C nitrate in soil protein synthesis B nitrogen-containing organic chemicals in plants ingestion digestion absorption protein synthesis nitrogen-containing organic chemicals in animals Adapted from: Biology: Marcus Barbour, Mike Boyle, Mike Cassidy, Kathryn Senior, Collins Educational 0-00-322327-2 (a) Identify the processes labelled A, B and C. A ___________________________________ B ___________________________________ C ___________________________________ [3] (b) (i) What soil conditions would promote and encourage process C? ______________________________________________________ ___________________________________________________ [1] (ii) How could farmers develop such conditions? ______________________________________________________ ___________________________________________________ [1] A2B1S8 3643 4 [Turn over (c) (i) What group of plants can carry out nitrogen fixation? Examiner Only Marks Remark ______________________________________________________ ___________________________________________________ [1] (ii) Such nitrogen fixation involves a mutualistic relationship between the plants and nitrogen-fixing bacteria. Explain the term mutualism in this context. ______________________________________________________ ______________________________________________________ ______________________________________________________ ___________________________________________________ [2] A2B1S8 3643 5 [Turn over 3 Viruses may invade the body and infect certain host cells, in which they proliferate and are then released to infect further host cells. The diagram below represents a viral-infected host cell and free viruses that have been released from an infected cell. Examiner Only Marks Remark viral antigen free viruses viral-infected host cell (a) Explain how cell-mediated immunity within the body leads to the destruction of viral-infected cells. _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [4] A2B1S8 3643 6 [Turn over (b) Explain how antibody-mediated immunity leads to the destruction of the free viruses. Examiner Only Marks Remark _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [4] A2B1S8 3643 7 [Turn over 4 Mammals maintain a high body temperature, generally within the range 35 to 40 C, and heat is lost to the external environment by Examiner Only Marks Remark radiation conduction and convection evaporation The relative amount of heat lost by each of these processes changes at different environmental temperatures. The table below shows data for the percentage contribution of each of the processes to the total heat loss at three temperatures. Percentage contribution to the total heat loss Environmental temperature/ C Radiation Conduction and convection Evaporation 25 67 10 23 30 41 33 26 35 4 6 90 (a) At which environmental temperature will the total amount of heat loss by the mammal be greatest? Explain your answer. _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] (b) The actual amount of heat loss by radiation was the same at each of the three environmental temperatures. Explain the differences in heat loss by radiation shown in the table. _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] A2B1S8 3643 8 [Turn over (c) Explain two physiological processes by which the body may lose heat at higher environmental temperatures. Examiner Only Marks Remark 1. _______________________________________________________ _________________________________________________________ _________________________________________________________ 2. _______________________________________________________ _________________________________________________________ ______________________________________________________ [4] A2B1S8 3643 9 [Turn over 5 The light-dependent stage of photosynthesis takes place on thylakoid membranes in chloroplasts. The diagram below summarises the processes that take place on the thylakoid membrane. LIGHT thylakoid membrane LIGHT primary electron acceptor reaction centre Examiner Only Marks Remark primary electron acceptor reaction centre X photosystem II photosystem I Flow of electrons (a) In the photosystems, light is absorbed by different pigments including chlorophyll a, chlorophyll b and carotenoids. Explain the advantage of the photosystems being composed of different types of pigments. _________________________________________________________ ______________________________________________________ [1] (b) Explain what happens within the photosystems prior to electrons being emitted from their respective reaction centres. _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] (c) Each photosystem has the electrons lost due to photoactivation replaced from different sources. State the source of the electrons in each case. A2B1S8 Photosystem I __________________________________________ Photosystem II _______________________________________ [2] 3643 10 [Turn over (d) State the name of the molecules labelled X. Explain what happens when electrons pass along these molecules. Examiner Only Marks Remark _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] (e) Explain what happens when electrons are picked up by the electron acceptor after photosystem I. _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] (f) Suggest the advantage of the molecules of the light-dependent stage being located in the thylakoid membranes. _________________________________________________________ ______________________________________________________ [1] A2B1S8 3643 11 [Turn over 6 The diagram below shows a kidney nephron. Filtration occurs between the glomerulus and Bowman s capsule and, as the filtrate moves through the rest of the nephron, changes occur in its composition. glomerulus Bowman s capsule proximal convoluted tubule loop of Henl (a) Changes in the composition of the filtrate as it moves through the nephron can be compared with the composition of the blood plasma and expressed as a filtrate:plasma ratio for individual substances. The graph below shows changes in the filtrate:plasma ratio for a number of substances within the proximal tubule. 2.0 urea Filtrate: plasma ratio 1.5 glucose chloride 1.0 e os uc gl 0.5 ney sed kid rizini in phlo 0 Bowman s capsule end A2B1S8 3643 Distance along proximal tubule 12 Henl s loop end [Turn over (i) The graph includes the filtrate:plasma ratio for glucose in a kidney that was treated with phlorizin. Phlorizin inhibits glucose transport in cells. Suggest an explanation for the change in the filtrate:plasma ratio for glucose in phlorizinised kidney. Examiner Only Marks Remark ______________________________________________________ ______________________________________________________ ___________________________________________________ [2] (ii) Explain the results for the following substances, in an untreated kidney, taking account of your answer to (i). Glucose _____________________________________________ ______________________________________________________ ______________________________________________________ Urea _______________________________________________ ______________________________________________________ ______________________________________________________ Chloride _____________________________________________ ______________________________________________________ ___________________________________________________ [5] (b) In mammals that live in deserts, the loop of Henl is much longer than in mammals living in environments where water is plentiful. Suggest an explanation for this adaptation. _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [3] A2B1S8 3643 13 [Turn over 7 Photograph 4.7 shows a high resolution transmission electronmicrograph (colour-enhanced) of a synapse between two neurones. Examiner Only Marks Remark (a) Identify the features labelled A and B. A ___________________________________ B ___________________________________ [2] (b) Describe the sequence of events in feature A that occur as a result of an impulse arriving there. _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [3] (c) Describe the subsequent sequence of events that would lead to an impulse firing in the post-synaptic neurone. _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [3] A2B1S8 3643 14 [Turn over (d) The width of the synaptic cleft is 20 nm, while the diffusion rate of substances across it is 40 m s 1. Calculate the time delay caused by the synapse. (Show your working in the space below.) Examiner Only Marks Remark Answer _____________________ [2] (e) Following synaptic transmission, events occur at the synapse to achieve recovery. Outline two of these events. 1. _______________________________________________________ _________________________________________________________ 2. _______________________________________________________ ______________________________________________________ [2] A2B1S8 3643 15 [Turn over Section B Examiner Only Marks Remark In this section you are expected to answer in continuous prose, supported, where appropriate, by diagrams. You are reminded that up to two marks in this question are awarded for the quality of written communication. [2] 8 Give an account of anaerobic respiration as a metabolic pathway, and of its role and consequences in exercising muscle. [13] _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ A2B1S8 3643 16 [Turn over Examiner Only _____________________________________________________________ Marks Remark _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ A2B1S8 3643 17 [Turn over Examiner Only _____________________________________________________________ Marks Remark _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ A2B1S8 3643 18 [Turn over Examiner Only _____________________________________________________________ Marks Remark _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ A2B1S8 3643 19 [Turn over S 4/07 3643 A2B1S8 528-011-1 20 [Turn over [Turn over A2B1S8 3643.02 A2B11IN1 A (for use with Question 7) GCE Biology Advanced Assessment Unit A2 1 Module 4: Co-ordination, Biochemistry and Environment Summer 2008 Photograph 4.7 Source: http://www.sciencephoto.com Post-synaptic neurone B

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Additional Info : Gce Biology May 2008 Assessment Unit A2 1 - Module 4: Co-ordination, Biochemistry and Environment
Tags : General Certificate of Education, A Level and AS Level, uk, council for the curriculum examinations and assessment, gce exam papers, gce a level and as level exam papers , gce past questions and answer, gce past question papers, ccea gce past papers, gce ccea past papers

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