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GCE JAN 2007 : (A2 1) Co-ordination, Biochemistry and Environment

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Centre Number 71 Candidate Number ADVANCED General Certificate of Education January 2007 Biology assessing Module 4: Co-ordination, Biochemistry and Environment A2B11 Assessment Unit A2 1 [A2B11] WEDNESDAY 10 JANUARY, MORNING 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 nine questions. You are provided with Photograph 4.6 for use with Question 6 in this paper. Do not write your answer on this photograph. For Examiner s use only Question Number 1 2 3 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. A2B1W7 2606 4 5 6 7 8 9 Total Marks Marks BLANK PAGE A2B1W7 2606 2 [Turn over Section A Examiner Only Marks 1 Remark The phytochrome pigment, found in plant leaves, exists in two forms known as P660 and P730, each of which can be converted to the other. The diagram below illustrates this relationship. light P660 660 A B P730 730 dark (a) Name the colour of light represented by A and B in the diagram. A ___________________________________ B ___________________________________ [1] (b) Describe, with reference to the phytochrome system, how flowering is controlled in short-day plants. _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _______________________________________________________ [4] A2B1W7 2606 3 [Turn over 2 The diagram below represents a nephron and associated blood vessels. Examiner Only Marks Remark afferent arteriole 1 2 3 Source: Adapted from Life Science on File: Human Biology, Facts on File Publications, Oxford 1986 Samples were removed using a micropipette from three sites labelled 1, 2 and 3 on the diagram. The samples were then tested using Benedict s reagent (a positive test indicates the presence of a reducing sugar) and Biuret reagent (a positive test indicates the presence of a protein). The results of the tests are illustrated in the table below (+++ represents a strong reaction, + represents a very weak reaction, represents no reaction). Sample site +++ +++ 2 +++ + 3 2606 Biuret test 1 A2B1W7 Benedict s test 4 [Turn over (a) Explain the Benedict s test results for the samples from sites 1, 2 and 3. Examiner Only Marks Remark _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _______________________________________________________ [3] (b) Explain the Biuret test results for the samples from sites 1, 2 and 3. _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _______________________________________________________ [3] A2B1W7 2606 5 [Turn over 3 Some of the earliest work on tissue transplantation, and specifically skin grafting, was carried out by Peter Medawar during World War II. He was working in a burns hospital, treating civilians injured in bombing raids, as well as soldiers and airmen from the battlefront. The most effective treatment for severe burns was to cover the burnt area as quickly and completely as possible with fresh skin, to prevent infection and loss of body fluids. Skin taken from another part of the patient s own body was the best solution, but was not always possible. Using skin from other donors could offer temporary relief, but the transplanted skin would always be rejected eventually. Nevertheless, non-self skin could last long enough to allow the healing process to start. In particularly bad cases, it would sometimes be necessary to apply a second transplant of skin to keep patients alive until their own healing processes could take over. Medawar noticed that a second application of non-self skin, taken from the same donor after the first graft had been rejected, would last only a few days, whereas the first may have lasted up to two weeks. Examiner Only Marks Remark 5 10 15 (a) With reference to the activity of T-lymphocytes, explain why non-self skin from a donor is rejected [line 11]. __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [4] A2B1W7 2606 6 [Turn over (b) Explain why a second application of non-self skin taken from the same donor after the first graft had been rejected, would last only a few days, whereas the first graft may have lasted up to two weeks [lines 15 to 18]. Examiner Only Marks Remark __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [3] (c) State two treatments now used to reduce the risk of tissue rejection. 1. ________________________________________________________ __________________________________________________________ 2. ________________________________________________________ _______________________________________________________ [2] A2B1W7 2606 7 [Turn over 4 Two experiments were undertaken to investigate aspects of phototropism in plant shoots. Examiner Only Marks Remark Experiment 1 light from above Shoot A Shoot B piece of glass piece of glass responses (a) Explain, as fully as possible, the responses of shoot A and B in experiment 1. _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ _______________________________________________________ [4] A2B1W7 2606 8 [Turn over Experiment 2 Examiner Only Marks Shoot C Remark Shoot D tinfoil cap ring of tinfoil unidirectional light responses (b) Explain concisely why, in unidirectional light, shoot C exhibits a tropic response while shoot D does not. _________________________________________________________ _________________________________________________________ _________________________________________________________ _______________________________________________________ [2] A2B1W7 2606 9 [Turn over 5 A local council commissioned a survey to find out how much carbon dioxide was being produced in the council area. The chart below shows the amount of carbon emitted by different sources over a one-year period. Examiner Only Marks Remark 40 CO2 production/103 tonnes y 1 35 30 25 20 15 10 5 0 people and pets domestic fuels vehicles industrial fuels (a) Calculate the proportion of the total carbon dioxide emissions that is produced by vehicles. (Show your working.) Answer __________________ [2] A2B1W7 2606 10 [Turn over The council wished to initiate a project of planting fast-growing willow trees to absorb carbon dioxide. It has been determined that, after 10 years of growth, one hectare of planted willows will absorb 50 103 tonnes of carbon dioxide. Examiner Only Marks Remark (b) Calculate the area of willow trees that would need to be planted to absorb the council area s carbon dioxide emissions over a 10-year period. (Show your working.) Answer __________________ [2] (c) Explain the purpose of the council s willow project. _________________________________________________________ _________________________________________________________ _________________________________________________________ _______________________________________________________ [2] A2B1W7 2606 11 [Turn over 6 (a) The diagram below summarises the light-independent stage of photosynthesis (Calvin cycle). Examiner Only Marks Remark CO2 ribulose bisphosphate X triose phosphate ribulose phosphate (i) Indicate on the diagram, with the letter A, where ATP from photophosphorylation is used in the cycle. [2] (ii) Identify compound X in the cycle. ____________________________________________________ [1] (iii) How many molecules of triose phosphate are required to make three molecules of ribulose phosphate? ______________________________________________________ ____________________________________________________ [1] (b) Photograph 4.6 is an electronmicrograph of part of a chloroplast. (i) Name the structures labelled 1 to 3. 1 ___________________________________ 2 ___________________________________ 3 ___________________________________ [3] (ii) Where in the chloroplast does each of the following processes take place? A2B1W7 2606 Photophosphorylation __________________________________ Fixation of carbon dioxide ____________________________ [2] 12 [Turn over 7 (a) In the mammalian eye, the iris adjusts the amount of light which enters. The diagram below shows the iris under different light conditions. Examiner Only Marks Remark muscle pupil (i) Describe how the circular and radial muscles function to adjust the amount of light entering the eye. _____________________________________________________ _____________________________________________________ _____________________________________________________ ___________________________________________________ [2] (ii) Explain why it is important that the amount of light entering the eye is adjusted to the light intensity available. _____________________________________________________ _____________________________________________________ _____________________________________________________ ___________________________________________________ [2] A2B1W7 2606 13 [Turn over (b) Light of high intensity stimulates the cones of which there are three types, each with a different type of iodopsin. The graph below shows the absorption of different wavelengths of light by the iodopsin contained within the different types of cone cell. iodopsin in blue absorbing cones Remark iodopsin in green absorbing cones 100 sensitivity of cone (amount of light absorbed as % of maximum) Examiner Only Marks iodopsin in red absorbing cones 75 50 25 0 400 500 wavelength of light/nm 600 700 Using the information in the graph, explain why the brain perceives light of wavelength 440 nm as blue __________________________________________________________ __________________________________________________________ light of wavelength 580 nm as orange __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [4] (c) State one reason for cone cells only functioning at high light intensity. __________________________________________________________ _______________________________________________________ [1] A2B1W7 2606 14 [Turn over 8 The diagram below shows the structure of an ATP molecule. Examiner Only Marks Remark NH2 N P P P C HC CH2 C X CH C N N N Y OH OH (a) (i) Name the nitrogenous base labelled X. ____________________________________________________ [1] (ii) Name the sugar labelled Y. ____________________________________________________ [1] ATP is the immediate source of energy for cellular processes. Energy is made available when ATP is hydrolysed and a bond is broken. (b) Show on the diagram, with an arrow, the bond that is broken during hydrolysis. [1] ATP is synthesised in mitochondria (during oxidative phosphorylation) and in chloroplasts (during photophosphorylation). (c) Describe four similarities in the way in which ATP is synthesised during oxidative phosphorylation and photophosphorylation. __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ __________________________________________________________ _______________________________________________________ [4] A2B1W7 2606 15 [Turn over (d) Identify two differences between oxidative phosphorylation and photophosphorylation. Examiner Only Marks Remark 1. ________________________________________________________ __________________________________________________________ 2. ________________________________________________________ _______________________________________________________ [2] (e) Name one other metabolic process in which ATP is synthesised. _______________________________________________________ [1] A2B1W7 2606 16 [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] 9 Give an account of the sequence of events which occurs as an impulse is propagated along an axon and is subsequently transmitted across a synapse. [13] _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ A2B1W7 2606 17 [Turn over Examiner Only _____________________________________________________________ Marks Remark _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ 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_____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ A2B1W7 2606 19 [Turn over Examiner Only _____________________________________________________________ Marks Remark _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ A2B1W7 2606 20 [Turn over Examiner Only _____________________________________________________________ Marks Remark _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ A2B1W7 2606 21 [Turn over THIS IS THE END OF THE QUESTION PAPER A2B1W7 2606 22 [Turn over A2B1W7 2606 23 [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 noti ed. S 2B1W7 2606 A 3/06 2600 9-031-1 24 [Turn over A2B1W7 2606.02 A2B11IN1 3 2 1 GCE Biology Advanced Assessment Unit A2 1 Module 4: Co-ordination, Biochemistry and Environment January 2007 Photograph 4.6 (For use with Question 6) Source: Sinclair Stammers/Science Photo Library

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Additional Info : Gce Biology January 2007 Assessment Unit A2 1 - Module 4: Co-ordination, Biochemistry and Environment
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