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GCE JUN 2008 : (AS 2) Physiology and Ecology

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Centre Number 71 Candidate Number ADVANCED SUBSIDIARY (AS) General Certificate of Education 2008 Biology assessing Module 2: Physiology and Ecology ASB21 Assessment Unit AS 2 [ASB21] FRIDAY 13 JUNE, AFTERNOON TIME 1 hour. 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. INFORMATION FOR CANDIDATES The total mark for this paper is 55. Section A carries 43 marks. Section B carries 12 marks. You should spend approximately 15 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. For Examiner s use only Question Number 1 2 3 4 5 6 7 8 Total Marks ASB2S8 3409 Marks Section A Examiner Only Marks 1 Remark The diagram below illustrates the structure of three types of white blood cell as seen using a light microscope. cell A cell B cell C (a) Identify the types of white blood cell A, B and C. A ___________________________________ B ___________________________________ C ___________________________________ [3] (b) Outline how white blood cell type C brings about the destruction of foreign material in the body. _________________________________________________________ ______________________________________________________ [1] ASB2S8 3409 2 [Turn over 2 The diagram below represents a transverse section through the stem of a herbaceous plant. Examiner Only Marks Remark Epidermis A B Xylem Phloem C (a) Identify the tissues labelled A to C. A ________________________ B ________________________ C ________________________ [3] (b) (i) Suggest one way in which the epidermis of a xerophytic plant would be adapted to help reduce water loss from the stem. ______________________________________________________ ___________________________________________________ [1] (ii) Explain how this adaptation of the epidermis helps prevent water loss. ______________________________________________________ ___________________________________________________ [1] ASB2S8 3409 3 [Turn over 3 The graph below shows the oxygen dissociation curve for human haemoglobin. Examiner Only Marks Remark Saturation with oxygen/% 100 75 50 25 0 0 2 4 6 Partial pressure of oxygen/kPa 8 10 (a) Explain the factors that influence the percentage saturation of haemoglobin with oxygen. (i) In the lungs ___________________________________________ ___________________________________________________ [1] (ii) In exercising muscle tissue _______________________________ ______________________________________________________ ______________________________________________________ ___________________________________________________ [2] (b) Describe and explain the affinity for oxygen of the haemoglobin of mammals living at high altitude. _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] ASB2S8 3409 4 [Turn over (c) Explain the role of myoglobin in mammals. Examiner Only Marks Remark _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] ASB2S8 3409 5 [Turn over 4 (a) The process of photosynthesis requires carbon dioxide. Describe and explain three features in a leaf that facilitate the availability of carbon dioxide for photosynthesis. Examiner Only Marks Remark 1. _______________________________________________________ _______________________________________________________ 2. _______________________________________________________ _______________________________________________________ 3. _______________________________________________________ ____________________________________________________ [3] (b) The graph below shows the effect of varying temperature and light intensity on the rate of photosynthesis. 4 Rate of photosynthesis/arbitrary units at high light intensity 3 2 at low light intensity 1 0 0 ASB2S8 3409 10 20 30 Temperature/ C 6 40 50 [Turn over (i) For the temperature range 0 C to 25 C, describe the effect of temperature and light intensity on the rate of photosynthesis. Examiner Only Marks Remark ______________________________________________________ ______________________________________________________ ______________________________________________________ ___________________________________________________ [2] (ii) Explain the effect of temperatures above 30 C. ______________________________________________________ ___________________________________________________ [1] ASB2S8 3409 7 [Turn over 5 The graph below illustrates the number of different species of young trees and the damage to the different species caused by the feeding activity of the Irish hare (Lepus timidus hibernicus) in a tree plantation in Ireland. 2000 Examiner Only Marks Remark 50 number of trees 40 30 1000 20 10 % of trees damaged by feeding hares Number of trees present in plantation % damaged 0 0 Oak Norway Spruce Alder Beech Ash Birch Larch Red Oak Tree species (a) Select two pieces of evidence from the graph to suggest that the hares are selective in their feeding and do not simply feed on what they find as they move through the plantation. 1. _______________________________________________________ _______________________________________________________ 2. _______________________________________________________ ____________________________________________________ [2] (b) Suggest one possible explanation for the hares selective feeding on the different species of trees. _________________________________________________________ ______________________________________________________ [1] ASB2S8 3409 8 [Turn over (c) Use the information in the graph to calculate the number of oak trees damaged by the hares. (Show your working in the space below). Examiner Only Marks Remark Answer ______________ [3] ASB2S8 3409 9 [Turn over 6 The diagram below shows part of the circulatory system in the human foetus. In the foetus, the placenta is the site of gaseous exchange. Examiner Only Marks Remark pulmonary artery foramen ovale aorta hepatic vein hepatic portal vein umbilical vein umbilical arteries placenta (a) The hepatic portal vein, which carries blood to the liver, originates in which organ? ______________________________________________________ [1] (b) The renal arteries are derived from which blood vessel shown above? ______________________________________________________ [1] (c) Into which heart chamber is blood returned in the foetal circulation? ______________________________________________________ [1] ASB2S8 3409 10 [Turn over The foramen ovale is an opening between the right and the left sides of the heart in the foetus. Examiner Only Marks Remark (d) Explain the effect that the foramen ovale has on the flow of blood through the heart. _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] (e) The foramen ovale closes shortly after birth. Explain why this is important. _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] ASB2S8 3409 11 [Turn over 7 Fertile grassland that is being heavily grazed by cattle has a high productivity but a low standing crop (biomass). Examiner Only Marks Remark (a) Explain how the grassland can have a high productivity and a low standing crop. _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] A typical square metre of grassland in Northern Ireland receives 1048000kJ of light energy from the sun each year. Only a small proportion of this energy is utilised in photosynthesis. Indeed, within each square metre, photosynthesis traps 21500 kJ of energy and, of this, 2000 kJ is used in respiration. (b) (i) Explain why only a small proportion of the available light energy is utilised in photosynthesis. ______________________________________________________ ___________________________________________________ [1] (ii) Determine the net primary production (NPP) over the year for one square metre of grassland. ___________________________________________________ [1] The efficiency of energy transfer to cattle feeding in grassland is approximately 5%, while about 15% of the energy in cattle is transferred to humans consuming beef. (c) Explain the difference in the efficiency of energy transfer to cattle as primary consumers and from cattle to humans as secondary consumers. _________________________________________________________ _________________________________________________________ _________________________________________________________ ______________________________________________________ [2] ASB2S8 3409 12 [Turn over There are both economic and health benefits for humans in feeding as primary consumers rather than as secondary consumers. Examiner Only Marks Remark (d) (i) Explain one economic benefit for the human population when feeding as primary consumers. ______________________________________________________ ___________________________________________________ [1] (ii) State one benefit to people s health in them feeding as primary consumers. ______________________________________________________ ___________________________________________________ [1] ASB2S8 3409 13 [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 how exchange or absorption is facilitated by each of the following surfaces. Alveoli Villi [10] Alveoli _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ ASB2S8 3409 14 [Turn over Examiner Only Marks Remark _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ Villi _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ _____________________________________________________________ ASB2S8 3409 15 [Turn over S SB2S8 531-005-1 A 2/07 0000 16 [Turn over

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Additional Info : Gce Biology June 2008 Assessment Unit AS 2 Module 2: Physiology and Ecology
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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