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GCE JAN 2010 : (A2 1) Physiology and Ecosystems - Revised

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Sp N ec e i w ca tio n Centre Number 71 Candidate Number ADVANCED General Certificate of Education January 2010 assessing Physiology and Ecosystems [AB211] AB211 Assessment Unit A2 1 *AB211* Biology MONDAY 25 JANUARY, AFTERNOON TIME 2 hours. 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. Write your answer to Section B on the lined paper at the end of this booklet. Answer all nine questions. You are provided with Photograph 4.4 for use with Question 4 in this paper. Do not write your answers on this photograph. INFORMATION FOR CANDIDATES The total mark for this paper is 90. Section A carries 72 marks. Section B carries 18 marks. Figures in brackets printed down the right-hand side of pages indicate the marks awarded to each question or part question. You are reminded of the need for good English and clear presentation in your answers. Use accurate scienti c terminology in all answers. You should spend approximately 25 minutes on Section B. You are expected to answer Section B in continuous prose. Quality of written communication will be assessed in Section B and awarded a maximum of 2 marks. 5916 For Examiner s use only Question Marks Number 1 2 3 4 5 6 7 8 9 Total Marks BLANK PAGE 5916 2 [Turn over Section A 1 The diagram below represents the structure of a neurone. synaptic bulbs A B C D Examiner Only Marks (a) Identify the structures labelled A to D. Remark A ________________________________ B ________________________________ C ________________________________ D ________________________________ [3] (b) Draw an arrow on the diagram above to indicate the direction of a nerve impulse travelling along the neurone. [1] (c) Explain why the neurone shown above might be expected to have a high speed of impulse conduction. _______________________________________________________ _______________________________________________________ _______________________________________________________ _____________________________________________________ [2] 5916 3 [Turn over 2 Many people have an immunity to measles as a result of either infection or vaccination. Measles vaccination starts with infants at 15 months. Examiner Only Marks Remark The measles antibody levels were measured in a group of babies during the first 24 months of life. The results for mean antibody levels are shown in the graph below. 160 120 Mean antibody levels/ 80 arbitrary units 40 0 6 birth 12 18 24 Time from birth/months (a) Explain the high levels of the measles antibodies in babies at birth and for the first six months. _______________________________________________________ _______________________________________________________ _______________________________________________________ _____________________________________________________ [2] (b) Explain the low levels of the antibody in babies after 12 months. _______________________________________________________ _______________________________________________________ _______________________________________________________ _____________________________________________________ [2] 5916 4 [Turn over (c) Explain why a measles vaccine would not be successful if given within the first six months. Examiner Only Marks Remark _______________________________________________________ _______________________________________________________ _____________________________________________________ [1] 5916 5 [Turn over 3 An oat seedling has a protective sheath (the coleoptile) which is frequently used as convenient plant material for experiments on phototropism. An experiment was carried out in which the tips of oat coleoptiles were removed and placed on blocks of agar. The agar blocks underneath each coleoptile were divided by thin sheets of metal. The tips of the coleoptiles were either illuminated evenly from above or from the right during this initial treatment period. The experiment set-up is shown in the diagram below. Light Coleoptile tip Block of agar A B Thin sheet of metal C Light D After the treatment outlined above the agar blocks then were placed on decapitated coleoptiles. The diagram below shows the height of the coleoptiles, initially (just after placement of the agar blocks) and finally (after 48 hours). A A C B B C D decapitated coleoptile Initial Initial Final Initial Final Initial Final Initial Final Examiner Only Marks Remark (a) Complete the diagram above by drawing a result for agar block D. [1] 5916 6 [Turn over (b) Explain the changes in height of the four coleoptiles. Examiner Only Marks Remark _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _____________________________________________________ [4] (c) Explain the reason for the inclusion of blocks A and B in the experiment. _______________________________________________________ _______________________________________________________ _____________________________________________________ [1] 5916 7 [Turn over 4 Photographs 4.4 A, B and C show three mammalian muscle types. Examiner Only Marks Remark (a) Identify the muscle types in each photograph and state one identifying feature for each. Photograph A Muscle type _____________________________________________ Identifying feature ________________________________________ _______________________________________________________ Photograph B Muscle type _____________________________________________ Identifying feature ________________________________________ _______________________________________________________ Photograph C Muscle type _____________________________________________ Identifying feature ________________________________________ _____________________________________________________ [6] (b) (i) Name the two protein filaments present in muscle fibres. _________________________________________ _________________________________________ [1] (ii) Describe the arrangement of these protein filaments in the myofibrils of a muscle fibre. ___________________________________________________ ___________________________________________________ ___________________________________________________ _________________________________________________ [2] 5916 8 [Turn over BLANK PAGE (Questions continue overleaf) 5916 9 [Turn over 5 The diagram below represents a pyramid of energy (productivity), for a Northern Ireland beef farm. The bars are not drawn to scale though the productivity of each level is indicated (as kJ m 2 y 1). Examiner Only Marks Remark Human tissue added (350) Beef produced (4000) Grass produced (62 431) Sunlight received (263 970 000) (a) Using the figures above, calculate the percentage efficiency of energy transfer from the sunlight received by the grass to the productivity of the grass. (Show your working.) ________________ [2] (b) The percentage efficiency of energy transfer from grass to beef is 6.4% while it is 8.75% from beef to human. Account for this difference. _______________________________________________________ _______________________________________________________ _______________________________________________________ _____________________________________________________ [2] 5916 10 [Turn over Modern farming can use a variety of techniques to increase food production for human consumption. Examiner Only Marks Remark (c) (i) Describe and explain one way in which the farmer could increase the yield of grass for his beef cattle to graze. ___________________________________________________ ___________________________________________________ ___________________________________________________ _________________________________________________ [2] (ii) Describe and explain one way in which the farmer could increase the yield of beef for human consumption. ___________________________________________________ ___________________________________________________ ___________________________________________________ _________________________________________________ [2] 5916 11 [Turn over 6 The diagram below represents the carbon cycle. Examiner Only Marks A Plant tissue Remark Atmospheric carbon dioxide B B Combustion C Animal tissue Death and waste Fossil fuels (a) Identify the processes labelled A to C. A _______________________________________ B _______________________________________ C _______________________________________ [3] (b) The combustion of fossil fuels illustrated in the diagram adds extra carbon dioxide to the atmosphere. Describe the consequences of a build up of carbon dioxide in the atmosphere. _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _____________________________________________________ [5] 5916 12 [Turn over (c) (i) Other gases are liberated into the atmosphere during the combustion of fossil fuels. Name one of these other gases which can cause acid rain. Examiner Only Marks Remark _________________________________________________ [1] (ii) Describe and explain one biological problem caused by acid rain. ___________________________________________________ ___________________________________________________ ___________________________________________________ _________________________________________________ [2] 5916 13 [Turn over 7 Graph A below illustrates how the application of insecticides may protect an orchard by reducing the numbers of the potentially crop-damaging leaf roller moth, Acleris rhombana. Graph B shows how a break in the application of the insecticide protects other orchard-dwelling animals such as the mites, Tetranychus uriticae and Stethorus punctum. Examiner Only Marks Remark Insecticide sprays Relative abundance A Leaf roller moth (Acleris rhombana) B Tetranychus uriticae Stethorus punctum June July August September (a) An orchard is an example of a monoculture . Explain why monocultures are particularly susceptible to pest infestations. _______________________________________________________ _____________________________________________________ [1] The insecticide used in the orchard is biodegradable. (b) (i) Identify one piece of evidence that suggests this insecticide is biodegradable. ___________________________________________________ _________________________________________________ [1] (ii) Explain why the use of a biodegradable insecticide is safer for the environment. ___________________________________________________ _________________________________________________ [1] 5916 14 [Turn over Spraying of the insecticide does not take place during the month of July so as not to affect other orchard species such as the mites, Tetranychus uriticae and Stethorus punctum. One of these species of mite is an important pest of the fruit trees which can cause blemishing of the orchard fruit. The other species is its predator. Examiner Only Marks Remark (c) Use the information in Graph B to help you to determine which mite species is the predator. Explain your answer. _______________________________________________________ _______________________________________________________ _____________________________________________________ [2] By not spraying insecticide in July, the population of predatory mites remains high and so reduces blemishing of the orchard fruit by keeping the pest population low. (d) (i) Name the type of pest control illustrated by this example. ___________________________________________________ (ii) Suggest one advantage of such a pest control system. ___________________________________________________ ___________________________________________________ (iii) Suggest one possible disadvantage of this form of pest control. ___________________________________________________ _________________________________________________ [3] 5916 15 [Turn over Biologists interested in the efficiency of such a pest control system may need to estimate the population of the leaf roller moths in the orchard using the mark/recapture technique. Examiner Only Marks Remark (e) (i) Describe how the biologists would carry out the mark/recapture technique to allow them to estimate the size of the population of moths. ___________________________________________________ ___________________________________________________ ___________________________________________________ ___________________________________________________ ___________________________________________________ _________________________________________________ [3] (ii) Suggest one assumption which must be fulfilled in order to obtain a valid estimate of the population size. ___________________________________________________ _________________________________________________ [1] 5916 16 [Turn over BLANK PAGE (Questions continue overleaf) 5916 17 [Turn over 8 In an experiment to investigate the functioning of the mammalian kidney, samples were taken by micropipette from different regions. The diagram below shows the sample sites, labelled 1 to 6. 1 6 2 3 5 4 Each sample was analysed to determine the concentration of glucose, protein, urea and sodium ions. The flow rate was also measured at each of the sample sites. The results are shown in the table below. Sample sites within the kidney Concentration/g dm 3 Urea Flow rate /cm3 min 1 Protein Glucose Sodium ions 1. Plasma in afferent arteriole 80 1.2 34 0.3 600.0 2. Filtrate in Bowman s capsule 0.5 1.2 34 0.3 125.0 0 0 34 1.6 25.0 0 0 70 1.8 1.5 0 0 30 1.8 1.5 0 0 45 2.2 1.3 3. End of proximal convoluted tubule 4. Bottom of loop of Henl 5. Beginning of distal convoluted tubule 6. Beginning of collecting duct Use the information in this table and your own understanding to answer the following questions. 5916 18 [Turn over (a) Explain the changes in the composition of proteins and glucose between the plasma in the afferent arteriole (sample site 1) and the end of the proximal convoluted tubule (sample site 3). Examiner Only Marks Remark Protein _______________________________________________ _______________________________________________________ _______________________________________________________ Glucose ______________________________________________ _______________________________________________________ _____________________________________________________ [4] (b) Comment on the changes in sodium ion concentration in the different sample regions. _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _____________________________________________________ [4] (c) Explain the changes in urea concentration as it moves along the nephron. _______________________________________________________ _______________________________________________________ _______________________________________________________ _____________________________________________________ [2] 5916 19 [Turn over (d) Suggest an explanation for the fall in the flow rate as fluid moves from the plasma into and then along the nephron. Examiner Only Marks Remark _______________________________________________________ _______________________________________________________ _______________________________________________________ _____________________________________________________ [2] (e) The experiment described on page 18 was carried out at 37 C. When the experiment was repeated at 30 C, the glucose concentration at the end of the proximal convoluted tubule was 0.15 g dm 3. Suggest an explanation for this result. _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _____________________________________________________ [3] 5916 20 [Turn over BLANK PAGE (Questions continue overleaf) 5916 21 [Turn over Section B Examiner Only Marks 9 Remark Quality of written communication is awarded a maximum of two marks in this section. [2] Give an account of the functioning of the mammalian eye to include the role of the following: the iris the lens rods cones [16] __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ 5916 22 [Turn over Examiner Only Marks Remark __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ 5916 23 [Turn over Examiner Only Marks Remark __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ 5916 24 [Turn over Examiner Only Marks Remark __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ 5916 25 [Turn over Examiner Only Marks Remark __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ 5916 26 [Turn over THIS IS THE END OF THE QUESTION PAPER 5916 27 [Turn over Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright holders may have been unsuccessful and CCEA will be happy to rectify any omissions of acknowledgement in future if notified. 5916 Photographs 4.4 A, B and C (for use with Question 4) A B C Lutz Slomianka 1998-2009 School of Anatomy and Human Biology - The University of Western Australia 5916.02

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Additional Info : Gce Biology January 2010 Assessment Unit A2 1 Physiology and Ecosystems - Revised
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