Life Sciences Grade 12 P1 NSC November 2019 Memo (English)

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE GRADE 12 LIFE SCIENCES P1 NOVEMBER 2019 MARKING GUIDELINES MARKS: 150 These marking guidelines consist of 11 pages + the master for the transparency to mark Question 2.3.5 Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 2 DBE/November 2019 NSC – Marking Guidelines PRINCIPLES RELATED TO MARKING LIFE SCIENCES 1. If more information than marks allocated is given Stop marking when maximum marks is 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. Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 3 DBE/November 2019 NSC – Marking Guidelines 14. If only the letter is asked for but only the name is given (and vice versa) Do not credit. 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 learners' 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. 19. Changes to the memorandum No changes must be made to the memoranda without consulting the provincial internal moderator who in turn will consult with the national internal moderator (and the Umalusi moderators where necessary). 20. Official memoranda Only memoranda bearing the signatures of the national internal moderator and the Umalusi moderators and distributed by the National Department of Basic Education via the provinces must be used. Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 4 DBE/November 2019 NSC – Marking Guidelines SECTION A QUESTION 1 1.1 1.1.1 B 1.1.2 C 1.1.3 C 1.1.4 A 1.1.5 B 1.1.6 C 1.1.7 A 1.1.8 B 1.1.9 A 1.1.10 D (10 x 2) (20) 1.2 1.2.1 Chorionic villi 1.2.2 Cytokinesis 1.2.3 Invasive alien/Invasive exotic 1.2.4 Vagina 1.2.5 Deforestation 1.2.6 Prolactin 1.2.7 Gestation 1.2.8 Fallopian tubes/Oviducts 1.2.9 Puberty (9) 1.3 1.3.1 A only 1.3.2 A only 1.3.3 B only (3 x 2) (6) 1.4 1.4.1 (a) Jelly layer/Zona pellucida (1) (b) Cytoplasm/cytosol (1) (c) Acrosome (1) 1.4.2 Oogenesis (1) 1.4.3 D (1) 1.4.4 E F (2) (Mark first TWO only) (7) 1.5 1.5.1 (a) Spinal cord (1) (b) Corpus callosum (1) 1.5.2 (a) D Cerebrum (2) (b) B Medulla oblongata (2) (c) E Cerebellum (2) (8) TOTAL SECTION A: 50 Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 5 DBE/November 2019 NSC – Marking Guidelines SECTION B QUESTION 2 2.1 2.1.1 (a) Centromere (1) (b) Homologous chromosomes (1) (c) Spindle fibre/spindle threads (1) 2.1.2 Anaphase II (1) 2.1.3 2, 1, 3 (2) 2.1.4 In metaphase I, the chromosomes arrange at the equator in homologous pairs whereas in metaphase II, the chromosomes arrange at the equator singly (2) (Mark first ONE only) (8) 2.2 2.2.1 Eggs are retained/hatch in the female body and the young are born live (2) 2.2.2 2 (1) (Mark first ONE only) 2.2.3 - The egg has the highest yolk/energy content - that will allow maximum development before hatching (2) 2.2.4 1 (1) (Mark first ONE only) (6) 2.3 2.3.1 Long-sightedness (1) 2.3.2 (a) - The lens becomes opaque/milky/cloudy - and therefore does not allow the light to pass through (2) (b) Surgery (1) (Mark first ONE only) 2.3.3 - The lens is less convex/the eye ball is too short/cornea is flat - This causes the light rays to fall behind the retina - A biconvex lens increases the refractive power - Therefore light rays are focussed on the retina to form a clear image (4) 2.3.4 Astigmatism (1) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 6 DBE/November 2019 NSC – Marking Guidelines 2.3.5 Percentage of (visually impared) people suffering from different visual detects Other Blindness Short- sightedness Long- sightedness Calculations: Blindness: 2/100 x 360° = 7,2° Short-sightedness: 30/100 x 360° = 108° Long-sightedness: 64/100 x 360° = 230,4° Other: 4/100 x 360° = 14,4° Criteria for assessing the graph: Pie chart drawn (T) 1 Title of the graph shows the relationship 1 between the two variables (H) Correct calculations to determine the 2: All 4 correct proportions (C) 1: 1-3 correct Correct proportions for the labelled sectors 2: All 4 sectors correct (P) 1: 1-2 sectors correct (To be checked using prepared transparency – see Annexure A – Page 12) (6) (15) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 7 DBE/November 2019 NSC – Marking Guidelines 2.4 2.4.1 - The high levels of progesteronein the pills - will inhibit the secretion of FSHfrom the pituitary gland - No follicle will develop - and hence no oestrogen will be secreted (4) 2.4.2 - The increase in the progesterone level - indicates that corpus luteum has been formed (2) 2.4.3 - Women will stay in the habit of taking a pill every day/will not forget to take the progesterone containing pills - To allow menstruation to occur Any (1) (Mark first ONE only) (7) 2.5 - Zygote divides by mitosis - to form a ball of cells - called the morula - which further divides to form a hollow ball of cells - called the blastula/blastocyst Any (4) [40] Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 8 DBE/November 2019 NSC – Marking Guidelines QUESTION 3 3.1 3.1.1 (a) ADH/antidiuretic hormone/vasopressin (1) (b) Aldosterone (1) 3.1.2 Adrenalgland (1) 3.1.3 3 (1) 3.1.4 - The blood will have a high salt content - and therefore less/no aldosterone will be secreted - resulting in less salt reabsorbed into the blood/more salt excreted in the urine - The blood will have less water than normal - and therefore more ADH will be secreted - making the kidney tubules more permeable - resulting in more water reabsorbed into the blood/less water will leave the body with the urine Any (5) (9) 3.2 3.2.1 Islets of Langerhans/pancreas (1) 3.2.2 Adrenalin (1) 3.2.3 Same: - Type of food given - Concentration of adrenalin - Amount of adrenalin - Measuring tools used - Person measuring the glucose concentrations - Levels of activity - Age of patients - Body mass of patients - Health condition of patients (Mark first THREE only) Any (3) 3.2.4 - Provides a baseline/starting level/point of reference/control - to compare with the effect of injecting adrenalin (2) 3.2.5 - Hormones are proteins - and will therefore be digested/denatured making it ineffective OR - Since it enters the blood directly - it will reach the target organs faster (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 9 DBE/November 2019 NSC – Marking Guidelines 3.2.6 - The blood glucose levels will increase - because an increase in adrenalin stimulates the conversion of glycogen to glucose (2) 3.2.7 Increases reliability of the results (1) (12) 3.3 3.3.1 - Biodiversity will decrease* - The flow of the river decreases/size of habitat decreases - This may affect migration patterns/spawning of fish - Opening of floodgates increases pressure of water flow 1 compulsory* + any 1 other (2) 3.3.2 - The water quality will decrease* - as the fertilisers increase the amount of nutrients/cause eutrophication - which will result in algal bloom - This will block-out the sunlight - The under-water plants cannot photosynthesise/die - Animals that feed on plants also die - This leads to an increase in decomposers feeding off the dead organisms - The decomposers deplete the oxygen in the water 1 compulsory* + any 4 others (5) 3.3.3 - Constant availability of water to increase crop yield - More food will be available and hence less money spent on buying agricultural products - More people are employed in the management of agriculture/dam/tourism therefore more income stability for the people in the community (Mark first ONE only) Any 1 x 2 (2) (9) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 10 DBE/November 2019 NSC – Marking Guidelines 3.4 3.4.1 8,7 – 3,8 OR 8,7 - (2,5 + 0,5 + 0,8) = 4,9  billion tons (2) 3.4.2 - There would be an increase in global warming* - The burning of plastic releases carbon dioxideinto the atmosphere - leading to the enhanced greenhouse effect - increasing the amount of heat trapped in the atmosphere - causing an increase in temperature 1 compulsory* + any 3 others (4) 3.4.3 - Supply special bins/garbage bags to encourage the collection of plastic - Bring recycling stations close to communitiesto increase access - Increase campaigns/ awareness/ education on the benefits of recycling - Giving incentives for collecting more plastics (Mark first TWO only) Any (2 x 2) (4) (10) [40] Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 11 DBE/November 2019 NSC – Marking Guidelines SECTION C QUESTION 4 Plant’s response to gravity (P) When a plant is placed horizontally: - auxins - are attracted by gravity Root - There is a high concentration of auxins on the lower side of the root - which inhibits growth/cell elongation/cell division on the lower side - There is a low concentration of auxins on the upper side of the root - which stimulates growth/cell elongation/cell division on the upper side - The upper side of the root grows faster/Uneven growth occurs - causing the root to grow/bend downwards - The root grows towards gravity/The root is positively geotropic Stem - There is a high concentration of auxins on the lower side of the stem - which stimulates growth/cell elongation/cell division on the lower side - There is a low concentration of auxins on the upper side of the stem - which inhibits growth/cell elongation/cell division on the upper side - The lower side of the stem grows faster/Uneven growth occurs - causing the stem to grow/bend upwards - The stem grows away from gravity/The stem is negatively geotropic (11) Maintaining balance (B) When the position of the head changes, the maculae: - are stimulated - The stimulus is converted to an impulse - which is transmitted by the auditory nerve - to the cerebellum - where the impulse is interpreted - The cerebellum sends impulses to the muscles - and balance is restored Any (6) Content (17) Synthesis (3) (20) ASSESSING THE PRESENTATION OF THE ESSAY Relevance Logical sequence Comprehensive All information provided is relevant to Ideas arranged in a logical/ Answered all aspects required by the question cause-effect sequence the essay in sufficient detail The following must be included: The sequence of events in the: All information is relevant to the: - Plant response to gravity (P) - Plant response to gravity - Plant response to gravity (7/11) - Maintenance of balance - Maintenance of balance - Maintaining balance (B) (4/6) are in a logical sequence There is no irrelevant information 1 mark 1 mark 1 mark TOTAL SECTION C: 20 GRAND TOTAL: 150 Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 12 DBE/November 2019 NSC – Marking Guidelines Annexure A – Master for transparency to mark Question 2.3.5 Copyright reserved