Life Sciences Grade 12 Paper 2 NSC June 2013 Question Paper

Downloaded from hlayiso.com basic education Department: Basic Education REPUBLIC OF SOUTH AFRICA SENIOR CERTIFICATE EXAMINATION BIOLOGY P2 HIGHER GRADE 2013 MARKS: 200 TIME: 2 hours BIOLOGY HG: Paper 2 3061E 30612E This question paper consists of 19 pages. X05 NUT GAUTENG Please turn over | Copyright reserved

Downloaded from hlayiso.com Biology/HG/P2 2 DBE/2013 SCE INSTRUCTIONS AND INFORMATION Read the following instructions carefully before answering the questions. ile 2. 10. ie Answer ALL the questions. Write ALL the answers in the ANSWER BOOK. Start the answer to EACH question at the top of a NEW page. Number the answers correctly according to the numbering system used in this question paper. You will lose marks if answers are not presented according to the instructions for each question. Do ALL drawings in pencil and label them in ink. Draw diagrams and flow charts only when requested to do so. The diagrams in this question paper are NOT necessarily drawn to scale. Do NOT use graph paper. You may use a non-programmable calculator, a protractor and a compass. Write neatly and legibly. Coit sen TUL eee

Downloaded from hlayiso.com Biology/HG/P2 3 DBE/2013 SCE SECTION A QUESTION 1 1.1 Various options are provided as possible answers to the following questions. Choose the correct answer and write only the letter (A-D) next to the question number (1.1.1—1.1.6) in the ANSWER BOOK. 1.1.1 In the leaves of a plant that grows in a dry environment, you would expect to find ... A B c D stomata on the upper surface only. approximately an equal number of stomata on both surfaces. more stomata on the upper than on the lower surface. more stomata on the lower than on the upper surface. QUESTIONS 1.1.2 and 1.1.3 are based on the following investigation. A learner investigated fat as an insulator. The learner used two thermometers. The learner wrapped fat around the end of one thermometer. The other thermometer had no fat wrapped around it. The learner left both thermometers in a freezer at -20 °C for some time. The table below shows the readings of the two thermometers before and after placing them in the freezer. Temperature before Temperature after placing in freezer in °C | being in freezer in °C Thermometer with no fat 20 -20 Thermometer wrapped in fat 20 7 1.1.2 Which idea was the learner testing in this investigation? A __ Animals that live in the Arctic are insulated better. B Fat reduces heat loss. C The thicker the layer of fat, the better the insulation. D_ Animals with fat can survive at lower temperatures. 1.1.3 The learner wanted to calculate the rate of temperature change of the two thermometers. To do this, the learner would also need to measure ... A B c D Copyright reserved the temperature of the room and the mass of the fat. the mass of the piece of fat and the temperature of the freezer. how long the thermometers were in the freezer and the mass of the fat. the temperature of the freezer and how long the thermometers were in the freezer. UAV AOR AA Pease tum over GAUTENG

Biology/HG/P2 Downloaded from hlayiso.com 4 DBE/2013 SCE A scientist decided to investigate whether there was a link between where polar bears live and the thickness of their body fat. To obtain valid results, the scientist should survey ... A __ polar bears of the same area. B__ polar bears and brown bears. C __ only polar bears living in areas with the coldest temperatures. D__ only male polar bears. The diagram below represents a laboratory set-up used by a student during an investigation of diffusion. Tube A Tubing 10 mé of water containing 5% sugar Tube B 10 me of distilled water Dialysis membrane An investigation of diffusion Copyright reserved Which statement best explains why the liquid in tube A will rise over a period of time? A The sugar concentrations are equal on both sides of the membrane. B- The water will pass from a region with a lower sugar concentration to one with a higher sugar concentration. C Water and sugar volumes are the same in both tubes A and B. D The water will pass from a region with a higher sugar concentration to one with a lower sugar concentration. Which of the following will increase the rate of transpiration? (i) Sunken stomata (ii) Large leaf area (iii) Thickened cuticle (iv) Hairs on the leaf (v) Many stomata A (ii) and (v) B (ii) and (ii) C (ii) and (iv) D (i) and (ii). (6x2) (12) ETO AAO IEE A Pease lumn over GAUTENG

Downloaded from hlayiso.com Biology/HG/P2 5 DBE/2013 SCE 1.2 Give the correct biological term for each of the following descriptions. Write only the term next to the question number (1.2.1-1.2.6) in the ANSWER BOOK. 1.2.1 The tendency of liquid molecules to rise spontaneously in narrow tubes 1.2.2 The pressure which develops in plant cells due to endosmosis 1.2.3 The group of plants where the stomata are sunken into the fleshy leaves 1.2.4 The ions that are removed from the blood by the kidney when the blood becomes too alkaline 1.2.5 A tube that carries urine from the bladder to the outside 1.2.6 The exudation of water in liquid form from tiny pores on the margin of leaves (6x 1) a6 Indicate whether each of the descriptions in COLUMN | applies to A ONLY, B ONLY, BOTH A and B or NONE of the items in COLUMN II. Write A only, B only, both A and B or none next to the question number (1.3.1—1.3.6) in your ANSWER BOOK. COLUMN | COLUMN II 1.3.1 The ability of a solution to do work A _ Water potential through osmosis B-Cell wall pressure 1.3.2. Transport of water A Xylem B_ Cell walls 1.3.3. Highest water potential A Pure water B__Hypotonic solution 1.3.4 Increases with an increase in the A __ Size of vacuole water potential of the cell sap B___Cell wall pressure 1.3.5 Strengthening of the xylem vessels | A Casparian strips B__Lignin 1.3.6 Function of the nephron A __ Excretion B__ Osmoregulation (6 x 2) Copyright reserved CAV AOAH UA A Pease tun over GAUTENG (6) (12)

Downloaded from hlayiso.com Biology/HG/P2 6 DBE/2013 SCE 1.4 Reflex actions are automatic and happen very quickly in order to protect the body from harm. For example, if you step on a drawing pin, you pull your foot away quickly. Explain what happens in the nervous system by indicating what happens at 1,2 and 3. A man steps on a drawing pin. | The stimulus is detected by receptors in the skin. J 1 The stimulus is converted to ... J 2 and conducted by the ... to the ... | 3 from where it is conducted by the ... J to the muscles that contract and lift the foot off the pin. Cot sen AHA) (1) (2) (1) (4)

Downloaded from hlayiso.com Biology/HG/P2 7 DBE/2013 Sea 1.5 An instructor carried out the first fitness session with a new member of the health club. Part of the instructor's role was to ensure that the member understood the reasons for certain recommendations. The instructor emphasised the importance of maintaining water balance during exercise and showed the member a chart listing the ways in which the human body gains and loses water in a 24-hour period. Study the table below and answer the questions that follow. Activity/Substance | Water gained Water lost (cm’) (cm*) Drinking 1 450 0 Food 800 0 Metabolism 350 0 Exhalation 0 400 Sweat 0 600 Urine 0 1500 Faeces 0 100 1.5.1 Other than eating or drinking, name TWO of the gains or losses that we can expect to increase during strenuous exercise. 1.5.2 Assuming that the member has a skin surface area of 3 m?, what is the approximate rate of water loss by sweating per hour from each m? of skin? State the correct unit in your answer. 1.5.3 The member commented that even though she drank an extra 500 cm? of fluid while she was exercising, she did not need to urinate. The instructor explained that this was due to the action of a particular hormone. Explain, by naming and describing the actions of the relevant hormone, why there was no need for the member to urinate while she was exercising. Copyright reserved COUTURE ACA A Pease tum over GAUTENG (2) (3) (5) (10)

Downloaded from hlayiso.com Biology/HG/P2 8 DBE/2013 SCE 1.6 Camels live in the desert and are adapted to cope with dry conditions and high temperatures. A scientist investigated the hypothesis that a camel that drinks lots of water can control its body temperature better than a camel that drinks little water. e He measured the body temperatures of two camels during the same day. e One camel did not have enough water to drink and the other had plenty of water available. e The living conditions of the camels were the same. The results are shown in the graph below. Body temperature of two camels during the same day 42 m1 TTT 40 eee 4 my, 38 | 36 34 Body temperature of camel in °C aan nnn sinensis pense 2 4 6 8 10 14 16 18 20 22 ” > om] i) 3 e) 5 g 5 = = = Time of day Key ---- Camel with plenty of water —— Camel with not enough water 1.6.1 What was the maximum body temperature of the camel who did not have enough water? (2) Copyrant reserved CHOU ATO EU A A Pease lum over

Biology/HG/P2 9 DBE/2013 SCE 1.6.2 Why is the camel with not enough water a suitable control in this investigation? 1.6.3 State TWO ways in which the results of the investigation can be improved. 1.6.4 Why did the body temperature of the camel with plenty of water vary less than that of the camel with too little water? 7 A learner carried out an investigation to determine the best plant growth Downloaded from hlayiso.com substance concentration for the development of adventitious roots. The learner took four stem cuttings and placed each in water with a different concentration of plant growth substance. The table below shows the results that the learner obtained. Plant growth substance Number of adventitious concentration in water (mg/) roots 0,10 3 1,00 10 10,00 5 100,00 1 1.7.1 1.7.2 1.7.3 7 1.7.5 Copyright reserved Name a plant growth substance that controls the growth of adventitious roots. State where the plant growth substance, named _ in QUESTION 1.7.1, is produced in plants. What is the best plant growth substance concentration for the cuttings? What conclusions can you draw from this investigation? State TWO other functions of plant growth substances. TOTAL SECTION A: EIU UAT UAE Pease turn over GAUTENG (2) (2) (2) (8) (1) (1) (1) (3) (2) (8) 60

Downloaded from hlayiso.com Biology/HG/P2 10 DBE/2013 SCE SECTION B QUESTION 2 2.1 Elodea is a freshwater plant. The diagram below represents one Elodea leaf cell in its normal freshwater environment. cell wall oO ao cytoplasm am Qi 2 & -——= organelles Elodea cell in fresh water _ Show, by drawing a labelled diagram of the Elodea cell, how the contents of the Elodea cell would change if the cell was placed in salt water for several minutes. (5) 2.1.2 Name the process you have illustrated in your diagram in QUESTION 2.1.1. (1) (6) Conreseved NAN A Pease tn oe

Biology/HG/P2 2.2 Downloaded from hlayiso.com 11 SCE DBE/2013 The masses of six sections of dialysis tubing, each containing 20 mf of a 25% sugar solution, were recorded. They were then placed in beakers each containing 100 mé solutions of varying sugar concentrations, as shown in the diagram below. 0% sugar 7 solution 25% sugar [ solution 15% sugar -- solution |_ 25% sugar solution Six sections of dialysis tubing placed in beakers 5% sugar -— solution 25% sugar [solution |. 20% sugar solution _. 25% sugar solution 10% sugar solution 25% sugar solution 25% sugar solution 25% sugar solution The sections of tubing remained in the beakers for 30 minutes. They were then removed and the outside of each section of tubing was blotted dry. Then the mass of each section of tubing was measured again. The mass change of each section of tubing in the different sugar solutions is indicated in the table below. 2.2.1 2.2.2 2.2.3 2.3 Copyright reserved Change in mass of in different dialysis tubing sections sugar solutions Sugar concentration Change in mass of in the beaker (%) the tubing (g) 0 5,1 5 4,7 10 4,4 15 2,5 20 1,4 25 0,0 Identify the process responsible for the change in mass of the dialysis tubing in the beakers. Describe the trend shown by the data in the table above. Use the data in the table to plot a line graph. GAUTENG Explain how the guard cells help to increase the rate of transpiration Please turn over (1) (2) (11) (14) (6)

Downloaded from hlayiso.com Biology/HG/P2 12 DBE/2013 SCE 2.4 A learner conducted an investigation to determine the effect of various environmental factors on the rate of transpiration in plants. The learner prepared four groups of plants. Each group contained 10 plants of the same species and leaf area. Each group was exposed to different environmental factors. The apparatus shown in the diagram below was constructed to measure water loss by the plants over time in 10-minute intervals for 30 minutes. NOTE: The water was topped up after each reading. plant water = -tube scaled in me Apparatus to investigate water loss through the leaves The results are shown in the data table below. Environmental factors Average total water loss in m@ over time O minutes | 10 minutes | 20 minutes | 30 minutes Classroom conditions 0,0 2,2 46 6,6 Classroom conditions + 0,0 4,2 7,6 11,7 Floodlight Classroom conditions + 0,0 4,5 7,6 11,0 Fan Classroom conditions + 0,0 13 2,4 “hy/ Mist (Moisture) 2.4.1 Identify ONE environmental factor that resulted in the lowest rate of transpiration. (1) 2.4.2 Identify the control group of plants in this experiment. (1) 2.4.3 Calculate the difference in total water loss in m? between the conditions with floodlights and fan conditions. Show your workings. (3) 2.4.4 Explain TWO precautions you would take in setting up the apparatus. (2x2) (4) (9) [35] Copyright reserved CAO Pease lum over GAUTENG

Downloaded from hlayiso.com Biology/HG/P2 QUESTION 3 13 SCE DBE/2013 3.1 Diagrams | and Il illustrate the lens and its associated structures as well as the pupil in front of the lens. The graph shows the changes in the shape of the lens over time. Diagram | 4 Most convex O a c 2 = te} o Q a = 7) G Least convex Diagram II Graph showing changes in the shape of the lens over time 2 4 6 Time in seconds 3.1.1 Identify parts A and B. Cont eseved NAN Please turn over (2)

Downloaded from hlayiso.com Biology/HG/P2 14 DBE/2013 SCE 3.1.2 Which Diagram (I or Il) shows the part of the eye: (a) Where the ciliary muscles are contracted. Give a reason for your answer. (b) Under dim light conditions. Give a reason for your answer. 3.1.3 Which letter on the graph indicates each of the following: (a) The eye looking at a nearby stationary object (b) The eye looking at an object moving towards the viewer 7. Explain the significance of the elastic nature of the lens. 3.2 Study the diagrams below and answer the questions that follow. Structure of a part of the human eye and a part of the human central nervous system 3.2.1 After only the sensitive coverings of the brain were injected to make them insensitive to pain, part B of a normal person was pierced with a sharp object, but the person did NOT experience any pain. (a) Give a possible explanation why the person did not experience a pain sensation. (b) Explain a possible disadvantage if a body part is pierced with a sharp object, but the person does not experience any pain. 2 (a) Identify parts A and C. (b) Give the letter of the part of the central nervous system that will interpret impulses conducted along part A. 3.2.3 Explain why damage to part D may lead to immediate death. Cont see A ALE, es mn (3) (3) (1) (1) (3) (13) (3) (5) (2) (1) (3)

Downloaded from hlayiso.com Biology/HG/P2 15 DBE/2013 SCE 3.2.4 Write down the letter of the part that is associated with the following: (a) Memory (1) (b) Muscle tone (1) (16) 3.3 Emperor penguins have adaptations that help them to survive in very cold and icy conditions. Oily feathers Streamlined body Layer of fat under the skin Emperor penguin Emperor penguins catch fish in the sea for food. Use this information and information from the drawing to explain how the Emperor penguin is adapted to survive in very cold and icy conditions. (6) [35] Coy oaed TUNA) Pes cr

Downloaded from hlayiso.com Biology/HG/P2 16 DBE/2013 SCE QUESTION 4 4.1 The human body loses water in several ways. The pie chart below shows the volume of water lost, in cm’, by amanona cold day. Pie chart showing volume of water lost in different ways on a cold day faeces (100 cm’) breathed urine (2 000 cm’) out el (300 cm’) ; YY sin — 4.1.1 The total volume of water lost by the man was 3 000 cm®. Be 4.1.3 Copyright reserved Calculate how much cm’ of water was lost through his skin. The same man lost 1 200 cm? of water through his skin on a warm day. Explain ONE reason for the different volumes of water lost on the two days. To maintain water balance in the body, the total volume of water taken in must equal the total volume of water lost. Give TWO ways in which this is achieved on a hot day, compared to on a cold day. FOTO A A A Pease un over (3) (2) (2) (7)

Biology/HG/P2 Downloaded from hlayiso.com 17 DBE/2013 SCE 4.2 On a hot sunny afternoon: * Man A sat in the shade, drinking a cold drink * Man B went jogging in the desert Man A Man B 4.2.1 Compare the volume and concentration of urine produced by the kidneys of the two men. 4.2.2 Explain the reasons for your answer to QUESTION 4.2.1 according to the information shown in the diagrams. 4.3 Study the table below which shows the concentrations of dissolved substances in the urine of a healthy person and in the urine of a person with a kidney disease. 4.3.1 4.3.2 4.3.3 Copyright reserved Concentration in grams per cm* ciel Urine of a healthy Urine of a person person with kidney disease Protein 0 6 Glucose 0 0 Amino acids 0 0 Urea 21 21 Mineral ions 19 19 Give an explanation for the difference in composition of the urine of the healthy person and the urine of the person with a kidney disease. State TWO processes that prevent glucose from being excreted in the urine. Explain why the urea concentration is higher in the urine than in the blood of a person. GAUTENG Please turn over (4) (4) (8) (4) (2) (2) (8)

Downloaded from hlayiso.com Biology/HG/P2 18 DBE/2013 SCE 4.4 Study the diagram below and answer the questions that follow. blood blood from back to patient patient coiled 7 bathing tubing [liquid Part of an artificial kidney machine 4.4.1 Explain why the tubule is coiled rather than straight. (2) 4.4.2 Explain why the bathing liquid must be replaced frequently with fresh liquid. (2) 4.4.3 Explain why the bathing liquid in the artificial kidney machine is normally kept at 37 °C. (2) (6) 4.5 Draw a labelled diagram to illustrate a Malphighian body of a human nephron. (6) [35] TOTAL SECTION B: 105 Conroe AA A A Pease tum over

Downloaded from hlayiso.com Biology/HG/P2 19 DBE/2013 SCE SECTION C QUESTION 5 5.1 Study the graph below and answer the questions that follow. Growth rates in boys and girls boys girls Growth rate (kg/year) 0 +++ ++ +++ 0 2° 4 G 8:10:12) 14°16 18 20. 22 Age (years) 5.1.1 Between which TWO years did the growth rate for boys and girls slow down the most? (2) _ Calculate the decrease in growth rate of girls during the period mentioned in QUESTION 5.1.1. (2) | At what ages did the growth rates for boys and girls reach a maximum? (3) 5.1.4 Between which years was the growth rate in girls higher than that of boys? (2) 5.1.5 Name ONE hormone involved in human growth. (1) 5.1.6 At what age, in years, did the girls reach their final adult size? (1) 5.1.7 Describe the differences between growth in males and females between the ages of four and eighteen years. (6) (17) 5.2 Discuss the concept of homeostasis by referring to the role played by the pituitary gland, the thyroid gland and the autonomic nervous system in regulating the metabolic rate of the body. Content: 15 Synthesis: 3 (18) TOTAL SECTIONC: 35 GRAND TOTAL: 200 Copmoreseres NNN HA