NYGH 2018-S3EOY-IP Bio P2 Section B

Class Register Number Name 南洋女子中学校 NANYANG GIRLS’ HIGH SCHOOL End-of-Year Examination 2018 Secondary Three IP BIOLOGY Paper 2 Theory Paper 1 hour 45 minutes Friday 5 October 2018 1000 – 1145 Additional materials: Nil READ THESE INSTRUCTIONS FIRST Do not open this document until you are told to do so. Write your name, register number and class in the spaces at the top of this page. Section B Answer three questions. Question 8 is in the form of an Either/Or question. Only one part should be answered. Write your answers in the spaces provided on the question paper. At the end of the examination, 1. fasten all your work securely together; 2. tick 8 Either or 8 Or in the grid-box to indicate the question answered. You are advised to spend no longer than 1 hour on Section A, and no longer than 45 minutes on Section B. The intended number of marks is given in the brackets [ ] at the end of each question or part question. The use of an approved scientific calculator is expected, where appropriate. Setter: LZJ This document consists of 8 printed pages. NANYANG GIRLS’ HIGH SCHOOL [Turn over B

2018 End-of-Year Examination Secondary Three 2 Nanyang Girls’ High School IP Biology Section B Answer three questions. Question 8 is in the form of an Either/Or question. Only one part should be answered. Write your answers in the spaces provided on the question paper. 6 A student carried out an investigation on cellular respiration. Glucose was dissolved in boiled and cooled water, before the yeast culture was added. 10 cm3 of yeast culture in glucose solution was added each to test-tubes A and B. In test-tube B, three drops of oil were carefully added to form a layer on the surface of the yeast culture. The apparatus was set up as shown in Fig. 6.1. Fig. 6.1 [adapted from Biology March 2015/P6] The appearance of the yeast cultures was recorded. The numbers of bubbles released from test-tubes A and B into the water were also counted and recorded. Observations and measurements were taken at five-minute intervals, the data was recorded in Table 6.1. yeast culture in glucose solution beaker of warm water beaker to support test-tube water water layer of oil delivery tube air tight stoppers A B

2018 End-of-Year Examination Secondary Three 3 Nanyang Girls’ High School IP Biology [Turn over Table 6.1 time / min appearances of yeast culture in A and B number of bubbles released in one minute A B A B 0 some bubbles no bubbles 0 0 5 foam starting to form on top some bubbles 7 4 10 thick foam on top foam starting to form below oil 12 7 15 thicker foam on top thin foam below oil 16 9 20 foam 3.0 cm in depth foam 0.5 cm in depth 20 10 (a) (i) On the gridlines below, using the same set of axes, plot the number of bubbles released in one minute against time for test-tubes A and B. Label each graph clearly. [5]

2018 End-of-Year Examination Secondary Three 4 Nanyang Girls’ High School IP Biology (ii) Using Table 6.1, compare and explain by comparing the results and observations for test-tubes A and B. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………[4] (b) Suggest why the number of bubbles released per minute would decrease for both test-tubes A and B after a period of 24 hours. …………………………………………………………………………………………………… ……………………………………………………………………………………………...…[1] [Total: 10] 7 Ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco) is an important enzyme

2018 End-of-Year Examination Secondary Three 5 Nanyang Girls’ High School IP Biology [Turn over involved in the light-independent stage of photosynthesis. This stage combines carbon dioxide (CO2) with RuBP to form molecules essential for glucose production. The reaction steps are illustrated in Fig. 7.1. rubisco CO2 + RuBP à à à à glucose Fig. 7.1 In certain situations, the active site of rubisco becomes occupied by a sugar-phosphate group, making the enzyme inactive. Rubisco can become active again in the presence of another enzyme, rubisco phosphatase. (a) Write the overall chemical equation for photosynthesis. ……………………………………………………………………………………………...…[2] (b) Suggest how rubisco phosphatase can activate rubisco. …………………………………………………………………………………………………… ……………………………………………………………………………………………...…[1] (c) The rate of photosynthesis in some plants can be affected by a process known as photorespiration. In photorespiration, rubisco combines oxygen with RuBP. During a particular botany research at high light intensities, the following observations were recorded: • a decrease in the rate of photosynthesis, • an increase in the rate of photorespiration. Suggest possible reasons for both changes in the rate of photosynthesis and photorespiration. …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… ……………………………………………………………………………………………...…[4] (d) (i) Sketch a line graph on the axes below to show the effect of temperature on the

2018 End-of-Year Examination Secondary Three 6 Nanyang Girls’ High School IP Biology rate of photosynthesis. Assume all other factors are kept constant. [1] (ii) Explain the shape of your graph in (d) (i). …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………[2] [Total: 10] Question 8 is in the form of an Either/Or question. Only one part should be answered. rate of photosynthesis / arbitrary units temperature / OC

2018 End-of-Year Examination Secondary Three 7 Nanyang Girls’ High School IP Biology [Turn over The quality of written communication will be highly regarded in your answer to this question. 8 Either (a) Describe the role of carbonic anhydrase in the excretion of carbon dioxide. …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… ……………………………………………………………………………………………...…[4] (b) Define double circulation of blood in humans and explain its significance. …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… ……………………………………………………………………………………………...…[6] [Total: 10] 8 Or

2018 End-of-Year Examination Secondary Three 8 Nanyang Girls’ High School IP Biology (a) Explain why lipids are the preferred energy storage molecules in the human body. …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………………………………………………………………………………………… …………………