Centre Number Candidate Number Candidate Name NAMIBIA SENIOR SECONDARY CERTIFICATE BIOLOGY ORDINARY LEVEL 4322/3 PAPER 3 Applied Practical Skills 2 hours Marks 60 2013 Additional Materials: Ruler L E V INSTRUCTIONS AND INFORMATION TO CANDIDATES • • • • • • • Candidates answer on the Question Paper in the spaces provided. Write your Centre Number, Candidate Number and Name in the spaces at the top of this page. Write in dark blue or black pen. You may use a soft pencil for any diagrams, graphs or rough working. Do not use correction fluid. You may use a non-programmable calculator. Do not write in the margin For Examiner’s Use. • Answer all questions. • The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use E L Y R A N I D R O 1 2 3 4 5 Total Marker Checker 110149 This document consists of 11 printed pages and 1 blank page. Republic of Namibia MINISTRY OF EDUCATION © MoE/DNEA 4322/3/13 723048 [Turn over 2 1 (a) For Examiner’s Use Fig. 1.1 shows the apparatus that can be used to show the loss of water from a plant. layer of oil water top pan balance Fig. 1.1 (i) Explain why oil is placed on top of the water in the flask. ............................................................................................................ ............................................................................................................ ............................................................................................................ ............................................................................................................ [2] (ii) Explain why the plant is added before the oil is carefully poured on top of the water. ............................................................................................................ ............................................................................................................ ............................................................................................................ ............................................................................................................ 4322/3/13 723048 [2] 3 For Examiner’s Use (iii) Explain how you would use this apparatus to measure the rate of transpiration, over seven days. ............................................................................................................ ............................................................................................................ ............................................................................................................ ............................................................................................................ ............................................................................................................ ............................................................................................................ ............................................................................................................ ............................................................................................................ [4] (iv) Outline the results you would expect if the experiment was repeated when the temperature is 10°C warmer. ............................................................................................................ ............................................................................................................ [1] (v) Using the same apparatus, describe how you could show that there are more stomata for water loss on the lower epidermis of the leaves than on the upper epidermis. ............................................................................................................ ............................................................................................................ ............................................................................................................ ............................................................................................................ ............................................................................................................ ............................................................................................................ ............................................................................................................ ............................................................................................................ ............................................................................................................ ............................................................................................................ [5] [14] 4322/3/13 723048 [Turn over 4 2 For Examiner’s Use Fig. 2.1 shows the apparatus that was set up in bright light and used to investigate photosynthesis in a leaf over a period of 12 hours. hydrogen carbonate indicator Fig. 2.1 The hydrogen carbonate indicator has the colour changes shown below. purple (air minus carbon dioxide) red (normal air) yellow (air plus carbon dioxide) (a) State the colour of the indicator at 0 hours.................................. and 12 hours ............................................ [2] (b) Describe how you would set up another tube to show that a leaf from the same plant respires. ....................................................................................................................... ....................................................................................................................... ....................................................................................................................... ....................................................................................................................... ....................................................................................................................... ....................................................................................................................... 4322/3/13 723048 [3] 5 For Examiner’s Use (c) (i) State the colour of the hydrogen carbonate indicator when the leaf has the same rate of respiration and rate of photosynthesis. ............................................................................................................ [1] (ii) Suggest what condition would you need to set up for the leaf to have the same rate of respiration and rate of photosythesis. ............................................................................................................ [1] [7] 4322/3/13 723048 [Turn over 6 3 (a) For Examiner’s Use A learner described the test for reducing sugars to another learner as follows. • Place a solid piece of food in a test-tube. • Quarter fill the test-tube with Benedict’s solution. • Heat the test-tube gently for 10 minutes. • A blue colour indicates the presence of a reducing sugar. The list given by the learner is incorrect in a number of ways. Describe the correct procedure for the reducing sugar test. 1..................................................................................................................... ....................................................................................................................... 2..................................................................................................................... ....................................................................................................................... 3..................................................................................................................... ....................................................................................................................... 4..................................................................................................................... ....................................................................................................................... [4] (b) Eight solutions, labelled A to H were tested for the presence of starch, protein, fat and vitamin C. The observations from these tests are given in Table 3.1. Table 3.1 solution colour after performing food test starch protein fat vitamin C A brown purple clear colourless B brown blue clear dark blue C brown blue cloudy dark blue D black blue cloudy dark blue E black blue clear dark blue F brown blue clear dark blue G black purple clear dark blue H brown blue clear colourless (i) Which solution(s) were found to contain 1 starch but no fats?............................................................................ [1] 2 protein but no vitamin C?................................................................. [1] 4322/3/13 723048 7 For Examiner’s Use (ii) Which solutions were obtained from plant extract? ................................................................................................................ [1] (iii) Which solution(s) might you consider to be pure water? ................................................................................................................ ................................................................................................................ [1] (iv) A learner suggested that solution D would provide the most energy. Explain the reasons why this learner selected this solution. ................................................................................................................ ................................................................................................................ ................................................................................................................ ................................................................................................................ [2] (v) Two other learners suggested that solution C or solution E would provide the most energy. Using the information in Table 3.1, explain why it is not possible to know which of the three learners is correct? ................................................................................................................ ................................................................................................................ ................................................................................................................ ................................................................................................................ ................................................................................................................ ................................................................................................................ [3] [13] 4322/3/13 723048 [Turn over 8 4 (a) For Examiner’s Use Fig. 4.1 is a photograph of insect A. X Y X5 Fig. 4.1 Make a large labelled drawing of the head of insect A. [6] (b) Fig. 4.2 is a photograph of insect B. Fig. 4.2 (i) List three similarities which are visible in the photograph of the two insects. 1.............................................................................................................. 2.............................................................................................................. 3.............................................................................................................. [3] 4322/3/13 723048 9 For Examiner’s Use (ii) Construct a table, with ruled lines, and record four visible differences, between insect A and insect B. [6] (c) The photograph in Fig. 4.1 shows insect A magnified X5. Measure the distance between points X and Y on Fig. 4.1 and use this measurement to calculate the magnification of your drawing, allowing for the X5 magnification of the photograph. Distance between points X and Y:................................................................. Magnification of your drawing:....................................................................... [4] [19] 4322/3/13 723048 [Turn over 10 5 The effect of pH on the activity of two protease enzymes, pepsin and trypsin, was investigated. An enzyme solution, adjusted to the required pH, was placed in a hole made in the middle of a layer of gelatin in a petri dish. Gelatin is a jelly made of protein. After one hour the activity of the enzymes was estimated by measuring the area of gelatin digested by the enzyme. The results are shown in Fig. 5.1 200 160 x area of gelatin digested 120 /mm2 x 80 x x x 40 x 0 1 2 3 x 4 5 6 pH Key Pepsin Trypsin Fig. 5.1 4322/3/13 723048 7 8 9 10 11 For Examiner’s Use 11 For Examiner’s Use Fig. 5.2 shows the apparatus used at the start of the experiment and after an hour. petri dish containing gelatin petri dish containing gelatin hole in gelatin containing enzyme solution 1 hour hole in gelatin containing enzyme solution 0 hour Fig. 5.2 (a) State the pH at which both enzymes had the same activity. ....................................................................................................................... [1] (b) One of the results was due to an experimental error. (i) Identify the enzyme ............................................................................................ and pH........................................................................................................... [1] (ii) Suggest three possible explanations for this experimental error. 1.............................................................................................................. ................................................................................................................ 2.............................................................................................................. ................................................................................................................ 3.............................................................................................................. ................................................................................................................ [3] (c) The optimum pH for pepsin is pH 2. This condition is found in the stomach. Explain how this condition is created in the stomach. ....................................................................................................................... ....................................................................................................................... ....................................................................................................................... ....................................................................................................................... [2] [7] 4322/3/13 723048 12 BLANK PAGE 4322/3/13 723048
