SPINE ROAD HIGH SCHOOL

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1 SPINE ROAD HIGH SCHOOL VIA AD SUCCESSORUM LIFE SCIENCES MARCH EXAMINATION 2017 GRADE 11 TIME: 2 hours MARKS: 120 EXAMINER: T.GABRIELS MODERATOR: Z. SHADE NSTRUCTIONS: Read the following instructions carefully before answering the questions. 1. Answer ALL the questions. 2. Skip a line between every sub question e.g and Start EACH question on a clean page. 4. Write ALL answers on the ANSWER SHEETS. 5. Start the answers to EACH question at the top of a NEW page. 6. Number the answers correctly according to the numbering system used in this question paper. 7. Write neatly and legibly. 8. ALL drawings should be done in pencil and labelled in blue/black ink. LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION

2 SECTION A QUESTION Various options are provided as possible answers to the following questions. Choose the correct answer and write only the letter (A to D) next to the question number (1.1.1 to 1.1.8) on your ANSWER SHEET, for example D The inner walls of the trachea and bronchi have a lining of: A. columnar epithelium B. cartilage C. ciliated epithelium D. squamous epithelium Which ONE of the following allows the lungs to move freely and without friction against the inner walls of the thorax? A. mucus within the bronchioles B. Moisture in the inhaled air C. fluid between the pleural fluid D. pulmonary blood supply Which of the following reactions would occur when there is an exchange of gas from the blood into the alveoli? A. carbon dioxide + water carbonic acid B. carbon dioxide + haemoglobin carbaminoheamoglobin C. carbonic acid hydrogen ions + bicarbonate ions D. hydrogen + bicarbonate ions carbonic acid carbon dioxide + water The maintenance of a constant internal environment in the body. A. negative feedback mechanism B. breathing C. excretion D. homeostasis The fluid that reduces fluid during inhalation and exhalation. A. interpleuaral fluid B. blood plasma C. water D. pericardial fluid LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION

3 1.1.6 The hormone which regulates the concentration sodium ions in the body. A. Aldosterone B. Antidiuretic hormone C. Adrenalin D. Thyroxin Which ONE of the following represents density dependent and density independent factors? Density dependent factors Density independent factors A fire and flood food supply and predation B disease and competition flood and drought C food supply and disease competition and predation D competition and fire flood and drought The net change in a population could be determined by. A. adding births and deaths subtracting emigration and immigration B. adding births and immigration and subtracting deaths and emigration C. adding births and emigration subtracting deaths and immigration D. adding deaths and immigration and subtracting births and emigration [8X 2][16] 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 to 1.2.6) on your ANSWER SHEET The mechanical process whereby air moves in and out of the lungs The structural and functional unit of the kidney Transport urine from the kidney to the bladder The one way movement of the organisms into an area where they become established The specific role each species plays in a community The blood vessel that transports blood towards the glomerulus. [6X 1][6] LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION

4 1.3 Indicate whether each of the statements in COLUMN I 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 to 1.3.4) COLUMN I COLUMN II Breathing muscle A intercostal muscle B diaphram Using census to determine the size of a population A direct technique B indirect technique Control the flow of urine A pyloric muscle B sphinter muscle Excess amino acids are broken down in the liver A uric acid B urea [2x 4] [8] TOTAL SECTION A: 30 LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION

5 SECTION B QUESTION A group of grade 11 learners set up the following experiment to demonstrate breathing, study the diagram below and answer the questions that follow Which parts of the human respiratory system is represented by A and D respectively? (2) Describe what will happen if the part labelled E was pulled downwards. (2) What breathing mechanism is being demonstrated when part labelled E is pulled downwards? (1) Describe ONE reason why the above model is NOT a truly accurate representation of the human respiratory system. (2) [7] LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION

6 2.2 Study the diagram alongside that shows an alveolus surrounded by a blood capillary Name the process associated with this diagram. (1) Identify the blood component labelled G. (1) State THREE ways in which the alveolus is adapted for its function (3) What kind of blood enters the capillary at A? (1) State TWO ways in which gas D is transported in the blood. (2) Name the process that occurs between B and E. (1) Explain how the process mentioned in QUESTION takes place. (3) [12] 2.3 A healthy man, with normal kidney function, is used in the following investigation. The amount of urine that he produced every 30 minutes (for an hour and half) is measured by collecting it, measuring the amount, calculating the average. He is then asked to drink one litre of water, urine is collected after 30 minute intervals. Study the results collected in table and answer the questions that follow. Time after drinking water (minutes) Urine produced (ml) LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION

7 2.3.1 State a suitable hypothesis for this investigation. (2) Identify the independent variable in this investigation. (1) Explain TWO ways could this investigation been made more accurate? (2) Draw a line graph to illustrate the results of this investigation. (6) After drinking a litre of water the man had increase of water in his blood. Describe how the water content in his blood was returned to normal. (6) QUESTION 3 [16] /35/ 3.1 The structure of the nephron can be used to determine the flow rate and composition of fluid in the human kidney. Samples of the fluid are taken at region A, B, C and D and E as shown on the diagram, which represents nephron and its associated blood vessels. F C A G H B E D Which part of the nephron is found in the medulla? (1) Explain how part C is adapted for its function? (2) Identify the blood vessels A and G respectively. (2) Which blood vessel mentioned in QUESTION contains the most urea. (1) LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION

8 The table below represent the results obtained Solute concentrations (g/100 cm 3 ) Region Flow rate (cm 3 / Plasma Glucose Urea min) proteins A ,5 0,5 0,04 B 100 0,0 0,5 0,04 C 20 0,0 0,0 0,15 D 15 0,0 0,0 0,95 E 2 0,0 0,4 1, Identify the processes associated with parts F. (1) A nephron plays a key role in homeostasis. Name any TWO homeostatic functions of a nephron. (2) Explain why part B contains no plasma proteins. (2) 3.2 Study the population growth pattern shown in the graph below and then then answer the questions that follow. [11] D E C A B Name the growth pattern shown in the above graph? (1) What does the dotted line at D represent? (1) Explain what the arrows represent and why some of the arrows are thicker than others. (3) LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION

9 3.2.4 Identify stages A and C respectively. (2) Briefly describe the growth pattern at stage B in the population growth pattern. (3) If this graph represents a sheep farm in the Karoo, what will happen to the line at D if the farmer introduces 200 sheep during stage C? (2) [12] 3.3 Study the following equation used to calculate changes in population size and answer the questions that follow. Equation: N = (B+I) (D+E) What does the letters N and E respectively in the above equation represent? (2) Explain what the following equation says about the population growth? B + I > D + E (2) Mention TWO limiting factors that regulate population growth. (2) [6] 3.2 A farmer has a game farm and wants to establish the number of impala that he has. On a set date, they build an enclosure. They then set out on horseback to round up 50 impala. Once the impala are safely in the enclosure, the animals are marked and set free. After two weeks, the animals are rounded up for the second catch of 42 impala. 10 marked impala were found in the second catch Calculate the estimated population of impala that the farmer has on his game farm. Show all your calculations (4) How will the farmer be able to improve the accuracy of the estimated population size of the impala that live on his farm? (2) [6] /35/ TOTAL SECTION B: 70 LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION

10 SECTION C QUESTION Describe the mechanism of the breathing process and explain how the correct level of the respiratory gases (carbon dioxide and oxygen) are restored soon after running a 100 m sprint. Content: 17 marks Synthesis (Relevance, the logical sequence and comprehension of facts): 3 marks NOTE: No marks will be awarded for answers in the form of flow charts, diagrams or tables. TOTAL SECTION C: 20 GRAND TOTAL: 130 LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION

11 SPINE ROAD HIGH SCHOOL VIA AD SUCCESSORUM LIFE SCIENCES MARCH EXAMINATION 2017 MEMORANDUM TIME: 2 hours MARKS: 120 EXAMINER: T.GABRIELS MODERATOR: M. FAIRBAIRN T. GABRIELS EXAMINER Z. SHADE M. FAIRBAIRN MODERATOR T.GABRIELS NSTRUCTIONS: Read the following instructions carefully before answering the questions. 9. Answer ALL the questions. 10. Skip a line between every sub question e.g and Start EACH question on a clean page. 12. Write ALL answers on the ANSWER SHEETS. 13. Start the answers to EACH question at the top of a NEW page. 14. Number the answers correctly according to the numbering system used in this question paper. 15. Write neatly and legibly. 16. ALL drawings should be done in pencil and labelled in blue/black ink. LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION

12 SECTION A QUESTION A C B D C C B D Nephron Ureter Trachea Medulla oblongata Immigration Afferent arteriole Both A and B A only B only B only [2X8] [16] [1X6] [6] [2X4] [8] TOTAL SECTION A: 30 LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION

13 SECTION B QUESTION B (1) INHALATION - The diaphragm contracts and becomes flattened. - The length of the thoracic cavity (top to bottom) is increased. - The external intercostal muscles contact and the rib cage is lifted. - The thoracic cavity is enlarged from side to side and from back to front. - The total volume of the thoracic cavity increases. - The pressure on the lungs/ interpleural pressure decreases - Since the atmospheric pressure is greater than the pressure on the lungs, air rich in oxygen is drawn in through the air passages into the lungs. (any 6) (6) Glass tube trachea rubber sheet diaphragm (2) The belljar doesn t move and so the volume inside the belljar remain the same unlike if inhalation takes place in the humans. OR When air move into the balloon it doesn t fill the entire space inside the balljar so the pressure in the belljar will remain the same and doesn t change like it does when inhalation take place in the humans (2) The balloon will not inflate and the pressure in the belljar will increase. (2) [13] X carbon dioxide Y Oxygen (2) Diffusion (1) Carbamino haemoglobin Bicarbonate ions Blood plasma (Any TWO) (2) Haemoglobin (1) [6] LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION

14 Urine production in ml during physical activity - carbon dioxide levels in the blood increase - chemoreceptors in the wall of the aorta is detects the imbalance in carbon dioxide levels - *sends a nerve impulse to the medulla oblongata - it then sends an impulse to the breathing muscles to contract and relax - the breathing rate increases and heart rate - More carbon dioxide is transported from the heart for exhalation - rate of inhalation increase - *oxygen levels in the blood increases and carbon dioxide in the blood decrease and return to normal [Mark any 4 facts + *compulsory points] [6] Drinking water increases urine production (2) Repeat this experiment Increase the sample size and include more participants Conduct this investigation on a hot and cold day and compare the results [Mark first 2 only] (2) Production of urine after drinking water for 4 hours Type 300 Plotting points Time after drinking water (minutes) Checklist for the mark allocation of the graph Correct type of graph 1 Title of graph 1 Correct label on the X and Y -axis 1 Appropriate scale for X and Y axis 1 Plotting points 2 marks if all points are plotted 1 mark if 6 points are plotted Total 6 [10] /35/ LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION

15 QUESTION Glomerular filtration / ultra filtration (1) C - Glomerulus E Cavity of the Bowmans capsule (2) Part labelled B is narrower than part labelled A. Narrow diameter of part B therefore resist the flow of blood by slowing down the rate of blood flow. This creates a higher blood pressure in part labelled C. The high blood pressure thus generated leads to leakage of blood plasma with smaller particles and other nitrogenous waste through the micro pores on the capillary network at C. Blood cells, plasma proteins and other large solutes are left behind in the blood. (Mark any 4 facts) (4) Podocytes (1) Presence of filtration slits between the podocytes act as selective filters allowing only small particles to pass through into the cavity of the bowmans capsule. (Any 2X1) (2) [10] Logistic growth form (1) Carrying capacity (1) The arrows represent environmental resistances. The thick arrows indicate the intensity of the environmental resistance, which limits population growth (3) B accelerating phase C equilibrium / stationary phase (2) The growth rate of the population is slow because the population is small - The individuals in the population are getting use to the environment - The rate of reproduction is slow - The individuals in the population are seeking mating partners - Gestation period takes time before offspring are born to increase the population size. (any 4) (4) This will cause the population to become unstable, decreasing the carrying capacity of the population caused by overgrazing. The farmer will not be able to support the same number of sheep. If the farmer relocates some of sheep to other farms and allow the land to rest (any 3). (3) [14] LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION

16 3.3.1 Mark recapture method (1) Steps to follow: 1. Decide on the method (use the butterfly net) to catch the grasshoppers 2. Mark the grasshoppers with non toxic paint on the upper thorax and record the total caught as the first catch 3. Set the grasshopper free for 2 hours to allow them to mingle in the population 4. Catch another round of the grasshopper and record the total of the second catch and the ones that were marked 5. Use the formula to determine the size of the population. (Mark first 4 only) (4) The method of catching the grasshoppers and the mark (paint used) must not change the behaviour of the grasshoppers The time between the first and second catch must be brief to prevent natality or mortality of the grasshopper population The mark (spot of paint) must not make the grasshopper visible to preditors (2X2) (4) N = M C R = 12 X 30/ 9 = 50 grasshoppers (2) [11] /35/ TOTAL SECTION B: 70 LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION

17 SECTION C QUESTION 4 When there is a shortage of water in the body due to sweating on a hot day or due to diarrhoea. The water concentration in the blood will be low. Osmoreceptors situated in the hypothalamus are stimulated. An impulse is sent to the Pituitary gland to secrete MORE ADH into the blood ADH travels in the blood to the renal tubes of the nephron. The renal tubes become more permeable to water. More water is transported out of the renal tubes into the surrounding blood vessels. Water content of the blood increases Less water remains in the renal tubes The urine is more concentrated. [max 10] Role of aldosterone in maintaining the salt balance in the blood. When the sodium concentration in the blood is low. Adrenal gland is stimulated. More aldosterone is secreted More sodium is reabsorbed from the renal tubes Salt is moved to the blood capillaries Sodium ions in the blood increases Less sodium forms part of the urine. [max 7] Content: (17) Synthesis (3) Criterion Relevance (R) Logical sequence (L) Comprehensive (c) Generally All information provided is relevant to homeostatic control of water and salt due to a shortage Ideas are arranged in a logical sequence for homeostatic control water in the blood Comprehend the role of aldosterone with regards to regulating the salt content of the blood of it. Mark TOTAL SECTION C: 20 GRAND TOTAL: 120 LIFE SCIENCE_ GRADE 11_ MARCH EXAMINATION