Life Sciences Grade 12 P1 NSC Supplementary 2016 Memo (Eng)

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE GRADE 12 LIFE SCIENCES P1 FEBRUARY/MARCH 2016 MEMORANDUM MARKS: 150 This memorandum consists of 10 pages. Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 2 DBE/Feb.–Mar. 2016 NSC – Memorandum 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. 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

Downloaded from hlayiso.com Life Sciences/P1 3 DBE/Feb.–Mar. 2016 NSC – Memorandum 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/Feb.–Mar. 2016 NSC – Memorandum SECTION A QUESTION 1 1.1 1.1.1 C 1.1.2 D 1.1.3 C 1.1.4 B 1.1.5 B 1.1.6 C 1.1.7 A 1.1.8 D 1.1.9 B 1.1.10 A (10 x 2) (20) 1.2 1.2.1 Vivipary/Viviparous 1.2.2 Centrioles/Centrosome 1.2.3 Geotropism/Gravitropism 1.2.4 Carbon footprint 1.2.5 Puberty 1.2.6 Stimulus 1.2.7 Grommets 1.2.8 Pinna (8 x 1) (8) 1.3 1.3.1 B only 1.3.2 Both A and B 1.3.3 B only 1.3.4 None (4 x 2) (8) 1.4 1.4.1 (a) A - penis (2) (b) E - testes (2) 1.4.2 (a) D and E (2) (Mark first TWO only) (b) B and C (2) (Mark first TWO only) (8) 1.5 1.5.1 (a) E (1) (b) A (1) (c) C (1) 1.5.2 F - motor neuron (2) 1.5.3 D to E (1) (6) TOTAL SECTION A: 50 Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 5 DBE/Feb.–Mar. 2016 NSC – Memorandum SECTION B QUESTION 2 2.1 2.1.1 (a) Round window (1) (b) Cochlea (1) 2.1.2 Cristae (1) 2.1.3 (a) - Impulses from the cochlea cannot be transmitted to the brain - and therefore hearing will not occur (2) 2.1.4 (b) - Part A will not be able to vibrate - The round window will not absorb the sound waves from the cochlea - and hearing will be affected (Any 2) (2) (7) 2.2 - Mucus in the middle ear - will lead to the blockage of the Eustachian tube - which will not be able to equalise the pressure in the middle ear - resulting in pressure on the tympanic membrane - that may cause the tympanic membrane to burst - leading to hearing loss (Any 4) (4) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 6 DBE/Feb.–Mar. 2016 NSC – Memorandum 2.3 2.3.1 Graph to show the relationship between ages of women and the percentage of pregnancies per month 30 25 24 Pregnancies per month 25 20 18 15 (%) 10 6 5 2 0 22 28 34 40 46 Ages of women (years) Mark allocation of the graph Criteria Mark Allocation Correct type of graph drawn for the 1 pregnancies per month only Title of graph including the two variables (Age of women and 1 pregnancies per month) Correct label and unit for X-axis 1 and Y-axis Correct scale for X-axis and Y-axis 1 Drawing of the graph 0: No points plotted correctly 1: 1 to 4 points plotted correctly 2: All 5 points plotted correctly NOTE: If axes are transposed: marks will be lost only for labelling of X-axis and Y-axis (6) 2.3.2 The older the women, the higher the chances of having miscarriages OR The younger the women, the lower the chances of having miscarriages (2) 2.3.3 50% x 12 = 6 OR 50 x 12 = 6 100 (2) (10) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 7 DBE/Feb.–Mar. 2016 NSC – Memorandum 2.4.1 2.4.1 - As a result of the blocked Fallopian tube - the sperm cannot reach the ovum - therefore fertilisation cannot take place (Any 2) (2) 2.4.2 (a) FSH/follicle stimulating hormone (1) (Mark first ONE only) (b) Oestrogen (1) (Mark first ONE only) 2.4.3 - A zygote is formed - which divides by mitosis - forming a ball of cells - called the morula - which further divides to form a hollow ball of cells (Any 4) (4) 2.4.4 - Progesterone levels would fall - The endometrium would no longer be maintained - A miscarriage would occur (3) (11) 2.5 2.5.1 Metaphase I (1) 2.5.2 - Crossing over has taken place - and genetic material was exchanged  (2) 2.5.3 Anaphase II (1) 2.5.4 - The spindle fibres contract - The centromeres split - and pull the daughter chromosomes/chromatids - to the opposite poles of the cells - Cytokinesis begins (Any 3) (3) 2.5.5 Testes/seminiferous tubules (1) (Mark first ONE only) (8) [40] Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 8 DBE/Feb.–Mar. 2016 NSC – Memorandum QUESTION 3 3.1 3.1.1 (a) ADH/antidiuretic hormone (1) (b) Hypothalamus/Pituitary gland (1) (c) Kidneys (1) 3.1.2 - An increase in ADH causes the walls of the kidney tubules - to become more permeable to water - More water is reabsorbed - and the blood volume increases - Less urine is produced - and the urine is more concentrated (Any 4) (4) (7) 3.2 3.2.1 Pancreas (1) 3.2.2 Insulin A Insulin B Glucose uptake peaks at a Glucose uptake peaks at higher level/around lower level/around 7 mg/kg/min 1 mg/kg/min All glucose uptake occurs in a Glucose uptake is gradual/ short period of time/the first sustained over a period of 5 hours 24 hours The initial uptake of glucose rises The initial uptake of glucose rapidly to a maximum within the rises slowly to the maximum first few hours over 5 hours A TABULATION IS NOT REQUIRED (Any 2 x 2) (4) (Mark first TWO only) (5) 3.3 3.3.1 (a) Amount of thyroxin (1) (b) Body weight (1) 3.3.2 - Same number of rats in each group - All rats were of the same species - All groups were investigated for the same period of time - All rats were the same gender - All groups were weighed after the same interval (Any 3) (3) (Mark first THREE only) 3.3.3 Group A (1) 3.3.4 - Low thyroxin levels - will lead to low metabolic rate - Therefore the energy from the diet is used very slowly - and more organic compounds are stored (Any 3) (3) 3.3.5 Group B (1) 3.3.6 - These rats have high levels of thyroxin in their blood - therefore pituitary gland will not be stimulatedto secrete TSH (2) (12) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 9 DBE/Feb.–Mar. 2016 NSC – Memorandum 3.4 3.4.1 - Poor infrastructure - Climate change - Wastage - Pollution of water sources (Any 2) (2) (Mark first TWO only) 3.4.2 - The need of water for irrigation will be reduced (1) 3.4.3 - Decreased production - will lead to loss of profit (2) 3.4.4 - More revenue for fixing poor infrastructure/building dams - Less water wastageby individuals and companies (2) (Mark first TWO only) (7) 3.5 3.5.1 (a) - Invasive alien plants reduce food security - since they grow rapidly and invade land - that could be used to grow crops (3) (b) - Invasive alien plants reduce water availability - since they use more water (2) 3.5.2 (a) - The new organism may become a pest itself/it may feed on indigenous plants instead of the targeted alien plant - since no natural enemy for it was brought into the area (2) (b) - Some parts that are left behind - can regrow/will cost more money to remove them again (2) (9) [40] TOTAL SECTION B: 80 Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 10 DBE/Feb.–Mar. 2016 NSC – Memorandum SECTION C QUESTION 4 Plant stems response to unilateral light - Plant stems response to light is positively phototropic - Auxins - produced in the tip of the stem - move away from unilateral light - so that there is a high concentration of auxins on the darker side - which stimulates growth/cell division/cell elongation - The low concentration of auxins on the side exposed to light - inhibits growth - This uneven growth - causes the stem to bend towards the light Max 7 How humans receive and interpret light stimuli - Light enters the eye  - through the cornea - which refracts the light - It then passes through the aqueous humour - and the pupil - The size of the pupil is adjusted by the iris - to regulate the amount of light that enters the eye - The light then passes through the lens - which also refracts the light - It then passes through the vitreous humour - and reaches the retina - which has the photoreceptors/rods and cones which convert the light stimulus into a nerve impulse Max 10 (10) Content: (17) Synthesis: (3) (20) ASSESSING THE PRESENTATION OF THE ESSAY Relevance Logical sequence Comprehensive All information provided is Ideas arranged in a logical/ Answered all aspects required by relevant to the question cause-effect sequence the essay in sufficient detail All the information provided is All the information regarding At least the following points relevant to plant stems' how plant stems respond to should be included: response to unilateral light and unilateral light and how - Plant response to unilateral how humans receive and humans receive and interpret light (4/7) interpret light stimuli. light stimuli are arranged in a - How humans receive and logical manner. interpret light stimuli (7/10) No irrelevant information. 1 mark 1 mark 1 mark TOTAL SECTION C: 20 GRAND TOTAL: 150 Copyright reserved