Life Sciences Grade 10 P3 National Exemplar 2012 QP (Eng)

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE GRADE 10 LIFE SCIENCES P3 (PRACTICAL) EXEMPLAR 2012 MARKS: 60 TIME: 1 hour This question paper consists of 4 pages. Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P3 (Practical) 2 DBE/2012 NSC – Grade 10 Exemplar QUESTION 1: OBSERVATION AND DRAWING SKILLS 20 MINUTES NOTE TO TEACHER Give learners the following items: microscope, onion (with epidermis removed), slide, cover slip, dropper and a small beaker of water 1.1 Make a wet mount slide of the onion epidermis. Your teacher will assess the preparation of your slide. (6) 1.2 Set up your microscope and then observe your slide under the microscope. Your teacher will assess the way in which you set up the microscope. (5) 1.3 Draw and label TWO cells of your specimen as seen under the microscope. (7) [18] QUESTION 2: CONDUCTING A PRACTICAL/INTERPRETING DATA 15 MINUTES NOTE TO TEACHER Give learners the following items: unknown sample (white powder – you may choose whether it should contain starch or not), boiled water in a beaker, a small test tube, iodine solution, Benedict's solution/Fehlings A and B, Biuret solution/Millon's reagent, water and a dropper 2.1 Test the unknown sample for the presence of starch. Write down whether it contains starch or not. Your teacher will assess the way in which you conducted the test. (5) 2.2 Study the table below which shows the results of certain tests on FIVE different food types: A, B, C, D and E. NAME OF TEST AND COLOUR CHANGE FOOD TYPE Benedict's/ Iodine Biuret/ Fehling's test test Millon's test A Orange Yellow Pale blue/White B Blue Black Pale blue/White C Orange Yellow Purple/Brick-red D Blue Black Purple/Brick-red E Orange Black Purple/Brick-red 2.2.1 Which food type (A, B, C, D or E) contains the following: (a) Only starch (2) (b) Only glucose (2) (c) Only protein and glucose (2) (d) Starch, glucose and protein (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P3 (Practical) 3 DBE/2012 NSC – Grade 10 Exemplar 2.2.2 Rice contains starch and protein, but no glucose. Which food type (A, B, C, D or E) is probably rice? (2) [15] QUESTION 3: DRAWING A GRAPH/INTERPRETING DATA 15 MINUTES NOTE TO TEACHER Set up the apparatus as shown in the diagram below. leafy shoot cotton wool test tube with water Apparatus used to investigate water loss from a leafy shoot The apparatus above was set up to investigate water loss from a leafy shoot. The total mass of the apparatus at the beginning of the investigation was 150 g. The apparatus was then weighed at 10-minute intervals over the next 50 minutes. After 50 minutes, the apparatus was taken outdoors and weighed every 10 minutes for another 50 minutes. The table below shows the decrease in mass of the apparatus over time in relation to the original mass of 150 g. INSIDE OUTSIDE Time (minutes) 0 10 20 30 40 50 60 70 80 90 100 Decrease in mass 0 1 3 4 5 9 11 21 24 33 39 (g) 3.1 Plot a line graph of these results. (7) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P3 (Practical) 4 DBE/2012 NSC – Grade 10 Exemplar 3.2 Name TWO environmental factors that could have caused the greater decrease in mass after 50 minutes. (2) 3.3 State ONE way in which the reliability of the results could have been improved. (1) 3.4 Calculate the mass of the apparatus after 80 minutes. Show your working. (2) [12] QUESTION 4: HEART DISSECTION 10 MINUTES NOTE TO TEACHER Dissect a sheep's/pig's heart to show its longitudinal section. Insert pins with flags/labels (A, B, C, D, E) on it as follows: A – Aorta B – (Left) ventricle (label should read Chamber B) C – Pericardium D – Tendon E – (Right) atrium (label should read Chamber E) F – (Right) ventricle (label should read Chamber F) Study the dissected heart with the labels and then answer the questions below. 4.1 Label parts A, B, C, D and E. (5) 4.2 State ONE function for each of parts A, D and E. (3) 4.3 Explain why the part labelled B has thicker muscular walls than the chamber labelled F. (3) 4.4 Explain the following: 4.4.1 Why are vessels found on the surface of the heart? (2) 4.4.2 Why does blood not move back into the atria when the ventricles contract? (2) [15] TOTAL: 60 Copyright reserved