LIFE SCIENCES P1 MEMO GR11 NOV 2020 ENG

NATIONAL SENIOR CERTIFICATE GRADE 11 NOVEMBER 2020 LIFE SCIENCES P1 MARKING GUIDELINE MARKS: 150 This marking guideline consists of 10 pages.

2 LIFE SCIENCES P1 (EC/NOVEMBER 2020) PRINCIPLES RELATED TO MARKING LIFE SCIENCES 1. If more information than marks allocated is given Stop marking when maximum marks are reached and put a wavy line and ‘max’ in the right-hand margin. 2. If, for example, three reasons are required and five are given Mark the first three irrespective of whether all or some are correct/incorrect. 3. If whole process is given when only a part of it is required Read all and credit the relevant part. 4. If comparisons are asked for, but descriptions are given Accept if the differences/similarities are clear. 5. If tabulation is required, but paragraphs are given Candidates will lose marks for not tabulating. 6. If diagrams are given with annotations when descriptions are required Candidates will lose marks. 7. If flow charts are given instead of descriptions Candidates will lose marks. 8. If sequence is muddled and links do not make sense Where sequence and links are correct, credit. Where sequence and links are incorrect, do not credit. If sequence and links become correct again, resume credit. 9. Non-recognised abbreviations Accept if first defined in answer. If not defined, do not credit the unrecognised abbreviation, but credit the rest of the answer if correct. 10. Wrong numbering If answer fits into the correct sequence of questions, but the wrong number is given, it is acceptable. 11. If language used changes the intended meaning Do not accept. 12. Spelling errors If recognisable, accept the answer, provided it does not mean something else in Life Sciences or if it is out of context. 13. If common names are given in terminology Accept, provided it was accepted at the national memo discussion meeting. 14. If only the letter is asked for, but only the name is given (and vice versa) Do not credit. Copyright reserved Please turn over

(EC/NOVEMBER 2020) LIFE SCIENCES P1 3 15. If units are not given in measurements Candidates will lose marks. Memorandum will allocate marks for units separately. 16. Be sensitive to the sense of an answer, which may be stated in a different way 17. Caption All illustrations (diagrams, graphs, tables, etc.) must have a caption. 18. Code-switching of official languages (terms and concepts) A single word or two that appear(s) in any official language other than the learner's assessment language used to the greatest extent in his/her answers should be credited, if it is correct. A marker that is proficient in the relevant official language should be consulted. This is applicable to all official languages. Copyright reserved Please turn over

4 LIFE SCIENCES P1 (EC/NOVEMBER 2020) SECTION A QUESTION 1 1.1 1.1.1 B  1.1.2 B  1.1.3 D  1.1.4 A  1.1.5 C  1.1.6 A  1.1.7 D  1.1.8 B  1.1.9 D  1.1.10 A  (10 x 2) (20) 1.2 1.2.1 Excretion  1.2.2 Epiglottis  1.2.3 Pharynx  1.2.4 Osmoregulation  1.2.5 Medulla oblongata  1.2.6 ATP /Adenosine triphosphate 1.2.7 Peristalsis  1.2.8 Glycolysis  (8 x 1) (8) 1.3 1.3.1 B only  1.3.2 None  1.3.3 A only  (3 x 2) (6) 1.4 1.4.1 (a) Renal vein  (1) (b) Urethra  (1) 1.4.2 (a) Inferior vena cava  (1) (b) Aorta  (1) 1.4.3 (a) E  – (Urinary) bladder  (2) (b) C  – Renal artery  (2) (c) D  – Ureter  (2) 1.5 1.5.1 Villus  (1) 1.5.2 (a) Lacteal  (1) (b) (Network of) blood capillaries  (1) 1.5.3 A (1) 1.5.4 Diffusion  and active transport  (2) TOTAL SECTION A: 50 Copyright reserved Please turn over

(EC/NOVEMBER 2020) LIFE SCIENCES P1 5 SECTION B QUESTION 2 2.1 2.1.1 (a) A – Glomerulus  (1) (b) B – Bowman’s capsule  (1) 2.1.2 (Ultra) filtration  (1) 2.1.3 (a) Proteins  (1) (b) Glucose  (1) (c) Urea  (1) 2.1.4 - The tubule is convoluted,  to allow sufficient time for re-absorption of useful nutrients / increases surface area for maximum absorption - The capillary network is in close contact with the tubule  to facilitate faster re-absorption of nutrients  - The cells of the inner wall of the tubule are richly supplied with many mitochondria  to generate energy for active absorption  (active transport) of nutrients back to the surrounding capillaries - The cells of the tubule have microvilli  to increase the surface area for maximum absorption  (Any 2 x 2) (4) 2.1.5 Patient with untreated diabetes mellitus will have glucose in the urine  (2) 2.2 2.2.1 Carbon dioxide/ oxygen is released during cellular respiration  (2) 2.2.2 Carbon dioxide  (1) 2.2.3 The clear lime water turns milky white in the presence of carbon dioxide  (1) 2.2.4 - Germinating seeds are actively growing plant parts  - therefore, the rate of respiration is higher  than in any other parts of the plant - since more energy  is required for the active growth process (Any 2) (2) 2.2.5 - No cellular respiration takes place in the dead seeds  - as a result, no carbon dioxide is released  therefore, clear lime water remains clear  (Any 2) (2) Copyright reserved Please turn over

6 LIFE SCIENCES P1 (EC/NOVEMBER 2020) 2.2.6 - There are spaces between the fibres of the cotton plug / gases can diffuse through cotton wool - allows the downward movement of carbon dioxide  OR - The rubber block does not allow the downward movement of carbon dioxide  - hence no result would be obtained  (2) 2.2.7 - Repeat the experiment several times  - use more seeds / increase sample size (Any 1) (1) 2.2.8 - Some of the cells in the seeds may contain chloroplasts  and therefore - they perform photosynthesis  - and disrupt the end result  (Any 1) (1) 2.2.9 - Temperature  - Light  (2) 2.3 2.3.1 Pancreas / Islets of Langerhans (1) 2.3.2 The glucose is a source of energy  as it is oxidised (broken down) during cellular respiration (1) 2.3.3 - When a person develops insulin resistance, - the body cells become incapable of using insulin effectively / unable to absorb sufficient amounts of glucose - This leads to an increase in the level of glucose in the blood  - which stimulates the pancreas to secrete extra insulin  - to enable the cells to absorb sufficient amounts of glucose  - Over a period of time, the pancreas’s ability to secrete extra insulin begins to decrease  - which leads to the development of type 2 diabetes (Any 4) (4) 2.3.4 - Glucose level in the blood increases above the normal levels  - The pancreas is stimulated  - to secrete insulin into the blood  - Insulin travels in the blood to the liver  - where it stimulates the conversion of excess glucose to glycogen  which is then stored - The glucose level in the blood now decreases and returns to normal (Any 4) (4) 2.4 2.4.1 To destarch  the plant / to allow plant to use up its starch reserves (1) 2.4.2 To check whether the leaf has been completely destarched / to confirm no starch (1) 2.4.3 (Diluted) iodine solution  (1) Copyright reserved Please turn over

(EC/NOVEMBER 2020) LIFE SCIENCES P1 7 2.4.4 - To prevent light from falling on covered part / shade the part from light - to serve as a control / so as to compare part in light and dark (2) 2.4.5 turns blue- turns brown  black  / / no starch contains starch Correct drawing and shading  (3) 2.5 - Surface area of the gas exchange organ must be large  in order to allow sufficient oxygen to diffuse  - Surface must be moist  gases diffuse through only in solution  - Surface must be thin  to allow for rapid diffusion of gases across it  - A transport system/ blood system must be available  to transport the - gases to and from the gas exchange surfaces  - An adequate ventilating mechanism must be present  to ensure that oxygen-laden air is brought in and carbon dioxide-laden air is driven out  - The gas exchange surface must be protected  because the gas exchange system is thin and delicate / so that it does not dry out (Mark first THREE only) (Any 3 x 2) (6) [50] Copyright reserved Please turn over

8 LIFE SCIENCES P1 (EC/NOVEMBER 2020) QUESTION 3 3.1 3.1.1 Between 0 – 2  arbitrary units  (2) 3.1.2 Photosynthesis  (1) 3.1.3 - No photosynthesis is taking place  - only respiration is taking place  (2) 3.1.4 6 mg /50 cm3  (2) 3.1.5 - The rate of photosynthesis equals  - the rate of respiration OR - Amount of CO2 being produced during respiration is equal to the amount of CO2 - taken up  during photosynthesis (2) 3.1.6 - The rate of photosynthesis remains constant  - because the optimum  concentration of CO2  for photosynthesis - has been taken up / - because chlorophyll molecules were saturated  - Enzymes are the limiting factor  (4) 3.2 3.2.1 (a) D – intercostal muscles  (1) (b) E – diaphragm  (1) 3.2.2 Ciliated  epithelial tissue (1) 3.2.3 The C- shaped cartilage rings keep the trachea open at all times  (1) 3.2.4 - Diaphragm contracts and becomes flattened  - The length of the thoracic cavity (i.e. top to bottom distance) is increased  - The external intercostal muscles contract and the rib cage is lifted  - This causes the thoracic cavity to be enlarged  - The total volume of the thoracic cavity increases  and - the pressure on the lungs 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 5) (5) Copyright reserved Please turn over

(EC/NOVEMBER 2020) LIFE SCIENCES P1 9 3.2.5 (a) Alveolus (1) (b) - The corona virus infection causes - the squamous epithelium  to become scarred and thickened - This prevents gaseous exchange  - between the alveolus and surrounding blood capillaries  - The accumulation of fluids in the pulmonary tube (bronchiole) prevents air flow to the alveolus  - Therefore, less oxygen is made available  - for cellular respiration  - resulting in organ failure due to lack of energy  (Any 4) (4) 3.3 3.3.1 (a) A – Duodenum  (1) (b) C – Gall bladder  (1) 3.3.2 - Secretes bile  - Is able to convert excess glucose to glycogen / stores glycogen - Stores minerals such as iron  - Stores vitamins such as A, D and B12  - Deamination of excess amino acids takes place in the liver  - Able to detoxify certain harmful substances and make them harmless  (Mark first THREE only) (Any 3) (3) 3.3.3 - The bile will not be released into the duodenum,  - therefore, no emulsification of fat is possible /not broken down into tiny droplets - This means that the enzyme lipase cannot digest fats into fatty acids and glycerol / lipase action is less effective (3) 3.3.4 - Very long  intestine/Part E ensures that the food remains in the alimentary canal for a long period for maximum absorption.  - The millions of villi  in the small intestine/Part E increase the surface area  for absorption - The walls of the villi are made up of a single row of columnar epithelial cells (thin walls) for easy absorption of digested nutrients  - The lacteal and capillaries  transport the absorbed food away quickly  - The columnar epithelial cells of the villi have microvilli  to increase the surface area for absorption  - The columnar epithelial cells have a high concentration of mitochondria  to provide energy  for active absorption of food (Any 4) (4) Copyright reserved Please turn over

10 LIFE SCIENCES P1 (EC/NOVEMBER 2020) 3.4 3.4.1 Chloroplast  (1) 3.4.2 Stroma  (1) 3.4.3 - Light phase / Light dependent phase - Dark phase / Light independent phase (2) 3.4.4 - The light phase takes place in the grana of the chloroplast  - which contain chlorophyll  - the chlorophyll absorbs light energy  - Part of the light energy is used to form ATP  - Part of the light energy is used for splitting water (photolysis) - into high energy hydrogen atoms  and - oxygen gas  which is released into the atmosphere as a by- product (Any 5) (5) 3.4.5 - At high temperatures, the protein molecules of the enzymes become denatured  - Therefore, the enzymes become functionless  - causing the metabolic process (photosynthesis) to stop  - Very low temperatures  slow down the rate at which photosynthesis takes place  (Any 2) (2) [50] TOTAL SECTION B: 100 GRAND TOTAL: 150 Copyright reserved Please turn over