GMSS 2018 Bio Prelim P2 QP

1 GMS(S)/BiologyP2/Prelim/2018/4Exp GMS(S)/BiologyP2/Prelim/2018/4Exp Candidate Name Class Index Number ____________________________________________________________________ BIOLOGY Paper 2 6093/02 Sec 4 Express Additional materials:Nil 1 hour 45 minutes Setter: Mrs Cheryl Tang 20 Aug 2018 READ THESE INSTRUCTIONS FIRST Write your name, index number and class on all the work you hand in. Write in dark blue or black penin both sides of the paper. Do not use staples, paper clips, highlighters, glue or correction fluid. Section A Answer all questions in the spaces provided on the question paper. Section B Answer allthe questions. Write your answers in the spaces provided on the Question Paper. Write an E(for Either) or an O(for Or) next to the number 10in the grid below to indicate which question you have answered. You are advised to spend no longer than one hour on Section A and no longer than 45 minutes for Section B. At the end of the examination, hand in the question paper. The number of marks is given in brackets [ ] at the end of each q u e s t i o n o r p a r t question. For Examiner’s Use Section A Section B 8 9 10 Total This document consists of 20printed pages and 2blank pages. [Turn over Geylang Methodist School (Secondary) Preliminary Examination 2018 www.KiasuExamPaper.com 298

2 GMS(S)/BiologyP2/Prelim/2018/4Exp Section A (50 marks) Answer allquestions. Write your answers in the spaces provided. 1 A group of students investigated the effect of soaking small onion bulbs in different concentrations of sodium chloride solution. They peeled off the outer papery leaves of the onion bulbs and divided the onions into 6 batches, e a c h w i t h 1 0 onions. The onions were surface dried with paper towels and weighed. The mean mass of the onions in each batch was calculated. The onions were then left in sodium chloride solutions for three hours. After three hours the students surface dried the onions and weighed them again. Their results are given in Table 1.1. Table 1.1 concentration of sodium chloride solution / g dm-3 mean mass of onions / g percentage change in mass/ %before soaking after soaking for 3 hours 0 147 173 +17.7 25 153 165 +7.8 50 176 172 -2.3 100 154 149 -3.2 150 149 142 -4.7 200 183 175 (a) (i) Explain why the students calculated the percentage change in mass of the onions. [2] (ii) Calculate the percentage change in mass of the onions that were in the most concentrated solution of sodium chloride. Show your working. Write your answer in Table 1.1. [1] www.KiasuExamPaper.com 299

3 GMS(S)/BiologyP2/Prelim/2018/4Exp (b)The students plotted a graph of the results as shown in Fig. 1.1. Fig. 1.1 (i) Complete the graph using your answer to (b)(i). [1] (ii) Use the graph in Fig. 1.1 to estimate the concentration of the sodium chloride solution that has the same water potential as the onions. [1] (c) Using the term water potential, explain why the onions change in mass when soaked in dilute solutions of sodium chloride. [2] [Total: 7] www.KiasuExamPaper.com 300

4 GMS(S)/BiologyP2/Prelim/2018/4Exp 2 Fig. 2.1 shows parts of the alimentary canal that lie in the upper part of the human body. Fig. 2.1 (a) (i) Name the part labelled E [1] (ii) Name the process that carries food from Fto G. [1] (b) Suggest why the walls of part Hare normally coated with mucus. [4] www.KiasuExamPaper.com 301

5 GMS(S)/BiologyP2/Prelim/2018/4Exp (c) Sometimes, particularly when a person is lying flat, partly digested food returns into structure Ethrough the valve at G. This can cause discomfort known as heartburn. (i) Suggest why heartburn is not a biologically accurate name for this condition. [1] (ii)Suggest and explain why medications for this condition are often alkaline in nature. [2] [Total: 9] www.KiasuExamPaper.com 302

6 GMS(S)/BiologyP2/Prelim/2018/4Exp 3 The menstrual cycle involves monthly changes in the ovary and the uterus. (a) Fig. 3.1 shows the sequence of changes within the ovary that occur during the menstrual cycle. Fig. 3.1 (i) Name structures Rand S. R S [2] (ii) State the name of the process that is occurring at T. [1] (b) The ovary secretes hormones that control the growth and maintenance of the lining of the uterus. Name the hormone that stimulates: (i) the growth of the lining of the uterus during the first half of t h e menstrual cycle [1] (ii) the maintenance of the lining of the uterus during the second half of the menstrual cycle. [1] [Total: 5] www.KiasuExamPaper.com 303

7 GMS(S)/BiologyP2/Prelim/2018/4Exp 4 There are many different drugs available to treat high blood pressure. Fig. 4.1 shows the mean heart rates of two groups of people, Jand K, over a five-year period. From the start, and throughout the period, group Kwere treated with a drug called a beta-blocker. Group Jdid not take any form of medication. Fig. 4.1 (a) (i) State the term used to describe group J. [1] (iii)Using information from Fig. 4.1, describe the effect on the heart of taking beta-blockers. [3] www.KiasuExamPaper.com 304

8 GMS(S)/BiologyP2/Prelim/2018/4Exp (b) On Fig. 4.1, draw a curve to show the expected effect on the mean heart rate of Group Jif, after three years, half of them started to take beta- blockers. [3] (c) Some other drugs reduce blood pressure by having an effect on b lood vessels. Suggest how these drugs may cause a decrease in blood pressure. [2] [Total:9] www.KiasuExamPaper.com 305

9 GMS(S)/BiologyP2/Prelim/2018/4Exp 5 A particular type of flower displays co-dominance and has multiple alleles. The alleles for purple (P) and red (R) are co-dominant and both the red and purple alleles are completely dominant to the white allele (W). Plant1produces purple flowers with patches of red. Plant2produces pure purple flowers. (a) Explain how you use the results of a test cross with Plant 2to determine if Plant2is heterozygous or homozygous for flower colour. [3] (b) Suppose the results of the test cross displayed that Plant 2is heterozygous. Using a genetic diagram, determine the ratios of the phenotype from a cross of Plant 1and Plant 2. [4] [Total: 7] www.KiasuExamPaper.com 306

10 GMS(S)/BiologyP2/Prelim/2018/4Exp 6 Fig. 6.1 shows a sloth. The sloth is a mammal that lives in the trees of the South American rainforests. Fig. 6.1 Sloths have the following features: • They are extremely slow moving. • Some tear leaves from trees using their lips and the teeth at the back of their mouths. • They have no front teeth. • They climb down the tree to deposit their faeces in a hole they dig near the foot of the tree. • They lose over a quarter of their body weight when they defaecate, which may be once every 6–8 days. • Their fur is often green since it contains single-celled, plant-like organisms (algae). • Their fur also contains blood-sucking mosquitoes and many small animals such as adult moths that feed on the algae and on the hair of the sloth. • Moths lay their eggs in the faeces of the sloth on which the moth larvae feed. • The major predators of the sloth are jungle cats and the harpy eagle. www.KiasuExamPaper.com 307