Zhonghua 2019 Bio Prelim P2 QP

ZHONGHUA SECONDARY SCHOOL PRELIMINARY EXAMINATION 2019 SECONDARY 4E Candidate’s Name Class Register Number 4E4 BIOLOGY 6093 /02 19 September 2019 1 hour 45 minutes Additional Materials: READ THESE INSTRUCTIONS FIRST Write your name, index number and class in the spaces at the top of this page and on all separate answer paper used. Write in dark blue or black pen. You may use a pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Section A Answer allquestions. Write your answers in the spaces provided on the question paper Section B For Examiner’s Use Answer all three questions, the last question is in the form either/or. Write your answers in the spaces provided on the question paper. Section A 50 B8 10 You are advised to spend no longer than one hour on Section Aand no longer than 45 minutes on Section B. B9 10 B10 10 At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. All essential working must be shown clearly. Total 80 Setter: Ms Rozianna Vetter: Mr Goh Tze Mian This document consists of 18printed pages, including this cover page. www.KiasuExamPaper.com 548

2 Total marks Section A Answer allthe questions. Write your answers in the spaces provided on the question paper. 1Large trees produce sun leaves on the outside of the canopy and shade leaves inside the canopy. Fig. 1.1 shows the rate of carbon dioxide uptake or production of a sun leaf and a shade leaf when exposed to increasing light intensity. Fig. 1.1 (a)Draw a line and letter X to label the light intensity at which the rate of respiration is equal to the rate of photosynthesis in the shade leaf on Fig. 1.1. [1] (b)With reference to Fig. 1.1, describe two ways in which the sun and shade leaf differ in their response to increasing light intensity. 1 2 [2] www.KiasuExamPaper.com 549

3 Total marks (c)Fig. 1.1 shows the results taken at a temperature of 20°C. Describe the effect on the sun leaf if the temperature was increased to 25°C. [3] (d)Outline an experimental plan to investigate the effect of carbon dioxide concentration on rate of photosynthesis. [3] [Total: 9] 2Fig.2.1 shows the series of events in a cardiac cycle of a man. The outer ring of the circle (Ato H) represents the sequence of events in the ventricles, while the inner ring (ato h) represents events in the atria. Fig. 2.1 systole (contraction) diastole (relaxation) 0.1 s AB C D E F G H a bc d e f g h www.KiasuExamPaper.com 550

4 Total marks (a)Calculate the heart rate of the man in beats per minute. Show your working. [1] (b)Identify the period (AtoH), at which (i) blood flows from the atria into the ventricles [1] (ii)the semi-lunar valves close [1] (c)Describe the events that occur in the heart during the period Ato C. [3] (d)An atrial septal defect is a condition where there is a small hole found in the wall of the heart between the left and right atria. Suggest why doctors advise patients with atrial septal defect to avoid vigorous sports. [1] [Total: 7] www.KiasuExamPaper.com 551

5 Total marks 3Table 3 shows the clearance time of some substances for a patient undergoing kidney dialysis. Table 3 substance in blood concentration in blood / mg/l time = 0 h time = 0.5 h time = 6 h urea 176 144 126 creatinine 3.4 2.7 2.5 glucose 134 128 138 potassium 4.3 4.1 4.1 sodium 143 137 135 chloride 108 107 (a) Complete Table 3 to show the estimated concentration of chloride at time = 0.5 h. [1] (b)Calculate the average hourly rate at which urea is removed from the blood of the kidney dialysis patient. Show your working. [2] (c) Explain the results when t = 6 h for potassium. [1] www.KiasuExamPaper.com 552

6 Total marks (d)The table did not show the concentration of proteins in blood. Predict how the trend of proteins would look like between t = 0 h to t = 6 h. Give a reason for your answer [2] (e) During each treatment, a patient has to undergo dialysis for a few hours. Suggest one way the time can be shortened. [1] [Total: 7] 4Fig. 4.1 shows the tissues of a mother and her fetus in a human placenta. The maternal blood and fetal blood remain separate. Fig. 4.1 (a) State a reason why there must be no mixing of fetal and maternal blood. [1] www.KiasuExamPaper.com 553

7 Total marks (b)The placenta is often described as “a small intestine, a lung a nd a kidney”. Explain how the placenta functions like the abovementioned organs. small intestine lung kidney [3] (c) Suggest two ways in which a pregnant mother could help in the healthy development of her fetus. [2] [Total: 6] www.KiasuExamPaper.com 554

8 Total marks 5Scientists are able to treat people with some types of brain damage. They may do this by injecting a patient with cells taken from another person (donor). These cells then migrate to the brain where they divide and specialise to become groups of fully functioning brain cells. (a) State the type of cell division that takes place when the injected cells reach the patient’s brain. [1] (b)State the term used to describe a group of cells that are specialised to perform a specific function. [1] (c) Female patients were injected with cells from male donors. After a period of time, the scientists examined brain cells from these patients and looked for groups of brain cells containing the Y chromosome. Explain why finding groups of brain cells containing the Y chromosome would suggest to the scientists that the treatment may have been successful. [3] [Total: 5] www.KiasuExamPaper.com 555

9 Total marks 6In the inheritance of the colour of cat fur, the allele for yellow fur (A) is dominant to the allele for grey fur (a). (a) Two heterozygous yellow-coloured cats produced offspring. Use a fully labelled genetic diagram to show how the colour of cat fur is inherited by the offspring. State the expected ratios of genotypes and phenotypes in the offspring. [5] A particular combination of these alleles is known as a ‘lethal’ combination. Young that inherit this combination die in the uterus during the very early stages of development. This results in a 2:1 ratio of fur colour in the surviving offspring. (b)Identify the lethal combination of alleles and explain how you reached this answer. lethal combination explanation [3] [Total: 8] www.KiasuExamPaper.com 556

10 Total marks 7Fig. 7.1 shows some of the interactions that take place in an aquatic ecosystem. Fig. 7.1 (a)Use the information in Fig. 7.1 to state the trophic level of aquatic plant trophic level of fish [2] (b)Explain one way, other than for food, that the fish may depend on the aquatic plant. [2] (c) Yrepresents the nitrification process responsible for the conver sion of nitrogenous compounds into nitrate ions. State the name of process Xand suggest the type of microorganism which carries out both processes Xand Y. process X type of microorganism [1] fish aquatic plant www.KiasuExamPaper.com 557