Life Sciences Grade 12 Paper 1 NSC June 2013 Question Paper

Downloaded from hlayiso.com guy “mle basic education Department: Basic Education REPUBLIC OF SOUTH AFRICA SENIOR CERTIFICATE EXAMINATION BIOLOGY P1 HIGHER GRADE 2013 MARKS: 200 TIME: 2 hours BIOLOGY HG: Paper 1 3061E 30611E This question paper consists of 17 pages. X@5 iI GAUTENG Please turn over | Copyright reserved

Downloaded from hlayiso.com Biology/HG/P1 2 DBE/2013 SCE INSTRUCTIONS AND INFORMATION Read the following carefully before answering the questions. 1. Answer ALL the questions. pe Write ALL the answers in the ANSWER BOOK. 7 Start EACH question at the top of a NEW page. 4. Number the answers exactly as the questions are numbered. 5: If answers are not presented according to the instructions of each question, candidates will lose marks. 6. ALL drawings should be done in pencil and labelled in ink. 7. Draw diagrams or flow charts only when requested to do so. 8. The diagrams in the question paper may NOT necessarily be drawn to scale. 9. Do NOT use graph paper. 10. You may use a non-programmable calculator, protractor and compass. 11. Write neatly and legibly. Comrie NAN Peet oe

Downloaded from hlayiso.com Biology/HG/P1 3 DBE/2013 SCE SECTION A QUESTION 1 77 Various options are provided as possible answers to the following questions. Choose the answer and write only the letter (A-D) next to the question number (1.1.1—1.1.10) in the ANSWER BOOK. 1.1.1 The gas needed for aerobic respiration is ... A nitrogen. B oxygen. Cc carbon dioxide. D hydrogen. 1.1.2 The gas required for aerobic respiration gets into an athlete's bloodstream by ... A diffusion from the lungs to the blood. B diffusion from the heart to the blood. Cc osmosis from the lungs to the blood. D osmosis from the heart to the blood. 1.1.3 The substance that makes up the rings of the trachea is ... A bone. B cartilage. Cc chitin. D calcareous. 1.1.4 Which of the following allows the lungs to move freely and without friction against the inner wall of the thoracic cavity? A Mucous within the bronchioles B Moisture in the inhaled air Cc Pulmonary blood supply D Fluid between the pleural membranes 1.1.5 Territoriality as a survival strategy ensures that: (i) The population exceeds carrying capacity (ii) There is sufficient breeding space (iii) The strongest animals provide for the next generation (iv) Interspecific competition occurs A (iand (ii) B (ii) and (iii) C (i), (i) and (iii) D (i), (iii) and (iv) cop econed NAN A Pose tm ove

Downloaded from hlayiso.com Biology/HG/P1 4 DBE/2013 SCE 1.1.6 The breathing centre in the medulla oblongata is most sensitive to changes in the ... A oxygen levels in tissue fluid. B glucose levels in blood. Cc ATP levels of mitochondria. D carbon dioxide levels in blood. 1.1.7 The sequence in which digested food moves along the alimentary canal, is ... A colon —» oesophagus —» ileum—» duodenum. B oesophagus —> ileum —» colon—» duodenum. Cc oesophagus —> duodenum —» ileum —> colon. D duodenum —» ileum —» colon —»oesophagus. 1.1.8 The first step during aerobic respiration is the ... A uptake of oxygen. B phosphorylation of glucose. Cc formation of ATP. D release of energy. The table below shows the population size of field mice in a maize field over a 5-year period. QUESTIONS 1.1.9 and 1.1.10 apply to the data shown in the table. Year Population of field mice 1990 12 1991 18 1992 76 1993 119 1994 120 1.1.9 Which of the following descriptions provides the best explanation for identifying the field mice as a population? A The group of field mice of the same species in a maize field over a 5-year period B The number of different species of field mice in a maize field Cc The group of field mice of the same species in any field over a 5-year period D The number of different species of field mice in any field Cortera ANA TIN!

Downloaded from hlayiso.com Biology/HG/P1 5 DBE/2013 SCE 1.1.10 The changes in the population size from 1992 to 1993 could be due to ... A unrestricted growth. B density-independent factors increasing. Cc the population reaching equilibrium. D environmental resistance gradually setting in. (10 x 2) (20) 1.2 Give the correct biological term for each of the following descriptions. Write only the term next to the question number (1.2.1-1.2.8) in the ANSWER BOOK. Ur The carriers of high-energy hydrogen atoms in the oxidative phosphorylation stage of respiration 1.2.2 The energy that plants absorb for photosynthesis 1.2.3 Air sacs which allow for gaseous exchange in the lungs 1.2.4 The part of the cell where the Krebs cycle occurs 1.2.5 The valve which controls movement of undigested food into the caecum 1.2.6 The opening that leads from the pharynx to the trachea 77 The type of tissue lining the air passages in the human body 1.2.8 The type of epithelium that lines the gaseous exchange surfaces (8) 1.3 Indicate whether each of the statements 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—1.3.5) in the ANSWER BOOK. COLUMN | COLUMN II 1.3.1 | Absorption of digested food A. Oesophagus B. Caecum 1.3.2 | Transports absorbed glucose to the liver A. Hepatic vein B. Hepatic-portal vein 1.3.3 | Requirements of a gaseous exchange A. Large surface area surface B. Moist 1.3.4 | Final product(s) of light phase of A. ADP photosynthesis B. Glucose 1.3.5 | Light bones projecting into nasal cavity A. Bronchioles B_Turbinates (5 x 2) (10) Copyright reserved CATA UA A Messe tm over

Downloaded from hlayiso.com Biology/HG/P1 6 DBE/2013 SCE 1.4 The diagram below represents the apparatus showing the results of an investigation with a certain species of bacterium and a species of the green algae, Spirogyra. The bacteria are attracted to oxygen. dark box with a narrow opening Apparatus I Apparatus Il Results of investigation with bacteria and green algae 1.4.1 Identify the process shown in the diagram above. (1) 1.4.2 Give an explanation for each of the following observations: (a) In Apparatus | the bacteria were found around the entire algal filament. (2) (b) — In Apparatus II the concentration of bacteria was found only around the algal filament where beams of light were allowed into the dark box. (2) (5) 1.5 Two individuals X and Y suffer from two different disorders as a result of malnutrition. Some of the symptoms/signs of each disorder are listed in the table below. Person X Person Y Puffy face Increased fatty tissue Swollen belly Narrowing of arteries Stick-like arms and legs Overweight 1.5.1 Name the disorder person X suffers from. (1) 1.5.2 Describe the diet of person X. (2) 1.5.3 Give ONE reason for the narrowing of the arteries in person Y. (2) Copyright reserved CHOU AAT OG IAG A A Messe tim over GAUTENG

Downloaded from hlayiso.com Biology/HG/P1 7 DBE/2013 SCE 1.5.4 Name ONE effect which could result from the disorder that person Y suffers from. (1) 1.5.5 State ONE way in which the disorder can be prevented in person Y. (2) (8) 1.6 Four pots of the same size (A, B, C and D) were filled with the same amount of soil. Seeds were planted in the pots as follows: Pot A — 2 mealie seeds and 2 pea seeds Pot B — 4 mealie seeds and 6 pea seeds Pot C — 8 mealie seeds and 8 pea seeds Pot D — 20 pea seeds The pots were watered well and left on a window sill. After 2 weeks the number of plants in each pot was counted. The average height of the plants above the ground (aerial part) was also determined. The results are shown in the table below. Number Average height of plants of plants (cm) PotA 6 8 Pot B 12 U Pot C 12 4 Pot D 12 2 161 In which pot (A, B, C or D): (a) Is a single population found (1) (b) Will the least competition for space in the pot occur (1) (c) | Was the least growth recorded (1) 1.6.2 Using an example from the above investigation, differentiate between intraspecific and interspecific competition. (6) (9) TOTAL SECTION A: 60 Copyrgns reserved FHI AUTOM EAA A Messe tim over

Downloaded from hlayiso.com Biology/HG/P1 8 DBE/2013 SCE SECTION B QUESTION 2 2.1 Study the diagram below and then answer the questions that follow. The human digestive system -_ Name TWO features of part D which increases its surface area. (2) 2.1.2 State TWO advantages of part D having an increased surface area, that you mentioned in QUESTION 2.1.1 above. (2) Ae Name TWO functions of organ C with reference to nutrition. (4) 2.1.4 Pepsin is an enzyme that is secreted in an inactive form in organ A. Explain why it is necessary for this enzyme to be secreted in an inactive form. (2) 2.1.5 Hydrochloric acid (HCI) provides the appropriate pH for pepsin to function optimally. Name TWO other functions of HCI. (4) 2.1.6 Explain why it is important that active absorption is employed in the small intestine for the end-products of carbohydrate and protein digestion. (3) 2.1.7 Describe the relationship between organs B and C. (4) (21) Coristrmored AN! Pv

Downloaded from hlayiso.com Biology/HG/P1 9 SCE DBE/2013 2.2 Some dieticians claim that a low-carbohydrate diet results in weight loss and a more healthy body than a low-fat diet. Scientists carried out an investigation to see if this claim is true. They used 120 overweight volunteers divided into two equal groups. Group 1 was given a diet containing less than 20g of carbohydrates per day. e Group 2 was given a low fat diet. This contained less than 30% of energy from fat and less than 300 mg of cholesterol per day. e Both groups were given the same exercise programmes and a weekly information meeting. e Both groups were allowed only 2 000 calories per day. The results after 24 weeks are shown in the table below. Group 1 Group 2 Low-carbohydrate Low-fat diet diet Percentage of volunteers who completed the trial 76 57 Mean/Average change in body mass as a -12,9 -6,7 percentage Mean change in body fat -9,4 -4,8 mass as a percentage 2.2.1 What is the independent variable in this investigation? (1) 2.2.2 Name TWO ways in which the method used by the scientists could have led to unreliable results. 2.2.3 Does the data support the claim by the dieticians? 2.2.4 Give ONE reason for your answer to QUESTION 2.2.3. (2) (1) (2) pts Why are both types of diet NOT recommended by most dieticians? (2) 2.3 Roughage plays a major role in nutrition in humans. 2.3.1 Name TWO sources of roughage. 2.3.2 Name TWO functions of roughage. Copyright reserved GAUTENG (8) (2) (4) (6) [35] Please turn over

Downloaded from hlayiso.com Biology/HG/P1 10 DBE/2013 SCE QUESTION 3 3.1 The laboratory set-ups below were used to investigate the effect of temperature on cellular respiration in yeast. Each of the flasks containing equal amounts of a yeast-glucose solution was submerged in a water bath, one kept at 20°C and one kept at 35°C. The number of gas bubbles released from the glass tube in each setup was observed and the results were recorded every 5 minutes for a period of 25 minutes. The data summarised in the table below. Water bath at 20°C fo} <x ° ° X Apparatus showing investigation at 20 °C Yeast-glucose solution o«<i__ Gas bubble L/7 Water 4 Water bath at 35°C +——, Water Gas bubble +— Glass tube § & : Yeast-glucose solution Apparatus showing investigation at 35 °C The table below shows the results obtained in the investigation. Time Total number of bubbles released (minutes) 20°C 35°C 5 0 e 10 5 15 15 15 30 20 30 50 25 45 75 3.1.1 3.1.2 3.1.3 3.1.4 Copyright reserved Using the information in the table above, plot a line graph to display the relationship between the number of bubbles released at 35 °C in the 25-minute period. (12) State the relationship between temperature and the rate of gas production in yeast. (3) Identify the gas released in this investigation. (1) Name the chemical used to test for the presence of the gas mentioned in QUESTION 3.1.3. (1) Name TWO factors that are controlled in the investigation. (2) (19) GAUTENG Please turn over

Downloaded from hlayiso.com Biology/HG/P1 a7 DBE/2013 SCE 3.2 The model below shows a portion of the rib cage and its associated muscles in the human body. Study the model and answer the questions that follow. Ww < 8 ra iz i} a 7) > a 7) < a 4 E 7) fi > a external aetna intercostal intercostal muscles relax Muscles contract and rib lowers to raise rib 3.2.1 Identify parts A, B and C. (3) 3.2.2 Which breathing mechanisms are represented by D and E respectively? (2) 3.2.3 What happens to the volume of the rib cage during mechanisms D and E respectively? (2) (7) at NTN cra

Downloaded from hlayiso.com Biology/HG/P1 12 DBE/2013 SCE 3.3 The diagram below shows capillaries found in tissue in the human body. Study the diagram and answer the questions that follow. A blood capillary ul 3.3.1 Name the liquid found between the cells of the tissue. (1) 3.3.2 Which vessel (A or B): (a) Is avein (1) (b) Contains the most deoxygenated blood (1) (c) | Contains the least carbon dioxide (1) 3.3.3 Name the gas that will move as indicated by X and Y respectively. (2) 3.3.4 State THREE forms in which the gas represented by X will be transported by the blood. (3) (9) [35] Cort mend IN|

Downloaded from hlayiso.com Biology/HG/P1 13 DBE/2013 SCE QUESTION 4 4.1 A class of students had to determine the number of dandelions on a certain area of the school field. The area had a length of 90 m and a breadth of 60 m. The students divided the area into quadrats of 1 m* each. The table below shows the results obtained for ten sample areas (quadrats). Sample number Number of dandelions 1 é 2 3 3 6 4 2 5 1 6 2 7 0 8 3 9 2 10 0 4.1.1 Name the indirect method used to determine the number of dandelions. (1) 4.1.2 Calculate the average number of dandelions of the ten sample areas (quadrats). Show clearly how you worked out your answer. (3) ae Estimate the total number of dandelions on the school field by using the results of sample 3 and the formula below: Total number = Number in sample x Total area of field Size of quadrat (4) 4.1.4 Is the estimation in QUESTION 4.1.3 reliable? (1) 4.1.5 Give ONE reason for your answer to QUESTION 4.1.4. (2) (11) Cort msn TTT crea

Downloaded from hlayiso.com Biology/HG/P1 14 DBE/2013 SCE 4.2 Study the population growth curve given below and answer the questions that follow. I ! s 2 I 8 ! 3 Ss a ! {o} a | | I | Time 4.2.1 What type of growth curve is shown in the graph? 4.2.2 Give a reason for your answer to QUESTION 4.2.1. 4.2.3 Identify the TWO phases of this population growth curve. 4.2.4 Name ONE factor that allows for the second phase named in QUESTION 4.2.3 to occur. 4.2.5 Give TWO possible reasons why this population growth cannot continue indefinitely. 4.3 Babies find it difficult to digest proteins in their food. Baby food manufacturers use enzymes to predigest the protein in baby food. 4.3.1 Name the group of enzymes that baby food manufacturers may use to predigest the protein. 4.3.2 What final product is formed when predigestion of proteins occur. 4.3.3 Why do baby food manufacturers need to predigest the protein in baby food? Copyright reserved (1) (2) (2) (1) (4) (10) (1) (1) (2) COUT UA ined GAUTENG

Downloaded from hlayiso.com Biology/HG/P1 15 DBE/2013 SCE 4.3.4 A baby food manufacturer uses enzyme V to predigest protein. The manufacturer tries four new enzymes, W, X, Y and Z, to see if he can reduce the time taken to predigest the protein in baby food. The graph below shows the time taken for the enzymes to completely predigest the proteins. The manufacturer uses the same concentration of enzyme and the same mass of protein in each experiment. 20 = 18 = < 16 § © 14 Qa £ 12 s = % 410 2 Ss 3 8 Qa 2 6 i— G4 a o £ Foo Vv Ww x v z Enzyme used (a) How long did it take enzyme V to predigest the protein? (b) Which enzyme, other than V, would you advise the baby food manufacturer to use? (c) Give ONE reason for your answer to QUESTION 4.3.4(b). (d) Enzymes are regarded as a biological catalyst. (i) Name the group of biological compounds that enzymes belong to. (ii) | Give TWO other reasons why the group of compounds named in QUESTION 4.3.4(d)(i) are biologically important. TOTAL SECTION B: (2) (1) (2) (1) (4) (14) [35] 105 cael TENT ca

Downloaded from hlayiso.com Biology/HG/P1 16 DBE/2013 SCE SECTION C QUESTION 5 5.1 Most breakfast cereal boxes contain a small label with nutritional information per 100 g. The table below is an example of this. Component Quantity Energy 1 045,0 kJ Protein 3,19 Carbohydrate 40,19 Fat 2,29 Fibre 25,6 g Iron 9,0 mg Vitamin B complex 18,39 Vitamin D 2,8 ug Vitamin A 3 ug 5.1.1 Give ONE reason why this breakfast will be regarded as a good breakfast. (2) 5.1.2 All items in the table account for about 98 g of the 100 g sample. Name ONE other important item of the diet that is likely to form most of the remaining 2 g in the 100 g sample. (1) a6 State ONE function of each of the following in humans: (a) VitaminA (2) (b) — Vitamin D (2) 5.1.4 Iron is an essential nutrient in any diet for the formation of red blood corpuscles. (a) | Name the substance found in a red blood corpuscle that contains iron. (1) (b) Name ONE disorder that is due to a lack of iron in a person's diet. (1) (9) Conritreoed NA A Pose tm

Downloaded from hlayiso.com Biology/HG/P1 17 DBE/2013 SCE 5.2 Several sets of test tubes, A to F, each containing 10 mé starch solution, 5 mé saliva and 5 mé of iodine solution, were prepared for an investigation. The tubes were placed in a water bath kept at 37 °C and the contents of each test tube was maintained at a different pH, as indicated in the table below. The time taken for the starch solution to show its reaction with the iodine solution in each set of test tubes was recorded. The results are indicated in the table below. Sets of test tubes Ch rLUcSlhLULULCULLCL pH value in test tubes 3 15,516,2]7,2] 7,8] 12 Average time taken for starch solution to show its reaction with the iodine solution 20;10;5]3]81]X (minutes) 5.2.1 Suggest an aim for this investigation. §.2.2 Name the enzyme that is responsible for the results in test tubes A toE. a6 At which pH is the enzyme named in QUESTION 5.2.2 at its optimum level of activity? 5.2.4 Explain your answer to QUESTION 5.2.3 above. 5.2.5 X in the table indicates no change shown in the reaction. When the contents of the test tubes of set F were changed to pH 9, it was found that this made no difference to the results. Give an explanation for this observation. 5.3 Photosynthesis is an important process for all living organisms and occurs in green parts of plants, such as leaves. State how photosynthesis benefits all living organisms and explain SIX ways in which the structure of the leaves of plants helps them to carry out the process of photosynthesis efficiently. Copyright reserved GAUTENG TOTAL SECTION C: GRAND TOTAL: Factual content: Synthesis: (2) (1) (1) (2) (2) (8) (15) (3) (18) 35 200