# Life Sciences Grade 12 P1 NSC Supplementary 2012 Memo (Eng) > Grade 12 Life Sciences Paper 1 memorandum from the NSC Supplementary 2012 (English), 11 pages. Read online or download the free PDF. - Page: https://www.hlayiso.com/library/life-sciences-p1-feb-march-2012-memo-eng-version-1/d7e2745b-603b-4629-a77e-018a8c8619f2 - Updated: 2026-09-27 - Subject: Life Sciences - Grade: Grade 12 - Document type: Memorandum - Year: 2012 - Exam period: NSC Supplementary - Paper: 1 - Curriculum: CAPS - Pages: 11 Breadcrumbs: [Home](https://www.hlayiso.com/) › [Library](https://www.hlayiso.com/library) › [Grade 12](https://www.hlayiso.com/library/grade-12) › [Life Sciences](https://www.hlayiso.com/library/grade-12/life-sciences) › [Life Sciences Grade 12 P1 NSC Supplementary 2012 Memo (Eng)](https://www.hlayiso.com/library/life-sciences-p1-feb-march-2012-memo-eng-version-1/d7e2745b-603b-4629-a77e-018a8c8619f2) ## About this document Life Sciences · Grade 12 · NSC Supplementary · 2012. Memorandum, 11 pages. Read online or download the PDF. Read it free online on the page above; download the PDF from there. ## Document text Text extracted from the PDF. Layout, diagrams and tables may not survive extraction. ### Page 1 Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE GRADE 12 LIFE SCIENCES P1 VERSION 1 (NEW CONTENT) FOR FULL-TIME CANDIDATES FEBRUARY/MARCH 2012 MEMORANDUM MARKS: 150 This memorandum consists of 11 pages. Copyright reserved Please turn over ### Page 2 Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 2 DBE/Feb.–Mar. 2012 NSC – Memorandum PRINCIPLES RELATED TO MARKING LIFE SCIENCES 2012 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 part of it is required Read all and credit relevant part. 4. If comparisons are asked for and descriptions are given Accept if 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 is incorrect, do not credit. If sequence and links becomes correct again, resume credit. 9. Non-recognised abbreviations Accept if first defined in answer. If not defined, do not credit the unrecognized abbreviation but credit the rest of 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 recognizable accept provided it does not mean something else in Life Sciences or if it is out of context. 13. If common names given in terminology Accept provided it was accepted at the National memo discussion meeting. Copyright reserved Please turn over ### Page 3 Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 3 DBE/Feb.–Mar. 2012 NSC – Memorandum 14. If only letter is asked for and only name is given (and vice versa) No 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 appears 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. No changes must be made to the marking memoranda without consulting the Provincial Internal Moderator who in turn will consult with the National Internal Moderator (and the External moderators where necessary) 20. Only memoranda bearing the signatures of the national Internal Moderator and the UMALUSI moderators and distributed by the National Department of Education via the Provinces must be used during training and during the marking period. Copyright reserved Please turn over ### Page 4 Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 4 DBE/Feb.–Mar. 2012 NSC – Memorandum SECTION A QUESTION 1 1.1 1.1.1 B33 1.1.2 C33 1.1.3 C33 1.1.4 A33 1.1.5 B33 1.1.6 A33 1.1.7 B33 1.1.8 D33 1.1.9 C33 1.1.10 B33 (10 x 2) (20) 1.2 1.2.1 Recessive3 1.2.2 Autosomes3 1.2.3 Cloning3 1.2.4 Polyploidy3 1.2.5 Genetic engineering3/Genetic modification/Biotechnology 1.2.6 Independent 3variable 1.2.7 Genome3 1.2.8 Locus 3 1.2.9 Extinction3 (9) 1.3 1.3.1 B only33 1.3.2 B only33 1.3.3 A only33 1.3.4 None33 1.3.5 Both A and B33 1.3.6 A only33 (6 x 2) (12) 1.4 1.4.1 A3 (1) 1.4.2 Opposable thumbs3with power and precision grip Bare fingertips3with nails Long arms3 Freely rotating arms3 Eyes in front3 Stereoscopic vision 3 Eyes with cones3 Large brain size compared to body mass3 Two mammary glands3 Sexual dimorphism3 Olfactory brain centre reduced3 (Mark first THREE only) Any 3 (3) Copyright reserved Please turn over ### Page 5 Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 5 DBE/Feb.–Mar. 2012 NSC – Memorandum 1.4.3 Humans3 (1) 1.4.4 Shift in the position of foramen magnum3 to a forward position Gently curved jaws3 Flat face3 Well developed chin3 Not prognathus3 Forehead less sloping3 No pronounced brow ridges3 Smaller canines3/ Spaces between teeth bigger3 Larger brain size3 (Mark first TWO only) Any 2 (2) 1.4.5 Rhesus monkey3 Gibbon3 (2) (9) TOTAL SECTION A: 50 Copyright reserved Please turn over ### Page 6 Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 6 DBE/Feb.–Mar. 2012 NSC – Memorandum SECTION B QUESTION 2 2.1 2.1.1 A – chromatid3/chromosome B – Spindle3 fibre (2) 2.1.2 Diagram 3, Diagram 2, Diagram 133 (in correct sequence) (2) 2.1.3 Crossing over3 in diagram 3 Chromosomes moving to poles3 in diagram 1 Bivalents (homologous pair of chromosomes) lie in the equator3 in diagram 2 (Mark first TWO only) Any 2 (2) (6) 2.2 2.2.1 Normal male karyotype has an X and Y chromosome 9 at 23 Klinefelter syndrome karyotype has an extra X chromosome 9/ 3 chromosomes at number 23/two X and one Y chromosomes (2) 2.2.2 During meiosis 1 9 the homologous chromosome pair 239 of the female 9parent does not separate9/there is non-disjunction OR During meiosis 2 9 the chromosome 239 of the female 9parent does not separate9/non-disjunction of chromosome and both chromatids move to same pole an ovum with 2 X chromosomes9 is produced during fertilization9 this ovum fused with a sperm cell with a Y chromosome9 to form the zygote with XXY 9/47 chromosomes Any 6 (6) (8) 2.3 Father Mother P1/parent phenotype No white forelock x White forelock 3 genotype hh x Hh 3 Meiosis Gametes H h G/gametes h, h x H, h3 h Hh hh h Hh hh Fertilisation OR 1 mark for correct gametes 1 mark for correct genotypes F1 genotype Hh , hh , Hh , hh 3 Phenotype 2 x without ‘white forelock’ & 2 x with 'white forelock' 3 Parents and offspring3/P1 and F1 Meiosis and fertilisation3 Max (6) Copyright reserved Please turn over ### Page 7 Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 7 DBE/Feb.–Mar. 2012 NSC – Memorandum 2.4 2.4.1 Co-dominance3 (1) 2.4.2 Both alleles3 expressed themselves equally3 in the phenotype3 of the offspring (3) 2.4.3 (a) RR33 (b) RW 33 (c ) WW33 (3 x 2) (6) (10) [30] QUESTION 3 3.1 3.1.1 To identify specific defective genes3/to find out if they are possible carriers (1) 3.1.2 - To be given advice on the risk of transferring the defective gene3/ to find the probability of passing on the defective gene to offspring - To be able to make decisions on whether they want to have children3 - To be given explanation of the results of DNA3 - To be given explanation of procedure to be involved in DNA testing3 (3) (Mark first THREE only) Any 3 (4) 3.2 Identify criminals3/biological evidence Identify deceased bodies3 Identify relatives3/ missing person/paternity (Mark first TWO only) Any 2 (2) 3.3 Australopithecus sediba Homo sapiens Smaller skeleton size3 Increased skeleton size3 Smaller cranium size3 Much larger cranium3 Less developed chin3 More developed chin3 3 x 2 + 1 table (7) 3.4 3.4.1 They can interbreed3 and produce fertile offspring3/puppies which can interbreed (2) 3.4.2 - there is variation in the wolves in terms of aggressive behaviour3/ feeding habits - a population of less aggressive/more tame wolves9 became scavengers9 around human settlements and were separated9 from the original wild population - each group occupying a niche undergoes natural selection3 - as a result of varying environmental conditions3 Copyright reserved Please turn over ### Page 8 Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 8 DBE/Feb.–Mar. 2012 NSC – Memorandum - and develops differently3 - genotypically3 and phenotypically3 - gene flow3/reproduction between the different populations does not occur - The differences that develop between the different populations prevent them from inter-breeding3even if they were to mix - such that one or both groups become a new species3 Max 6 (6) 3.4.3 Humans3 chose the dogs that had the best/desired characteristics3and interbred3 them Over many generations3 of careful selection a desired breed of dog was achieved Any 2 (2) (10) 3.5 3.5.1 Accepted3/not rejected (1) 3.5.2 The bacteria3/single-cell organisms appear in the oldest rock layers3/strata/multi-celled3/complex organisms appear later in Palaeozoic era3/older era3 is equivalent to older rock strata3 Any 2 (2) 3.5.3 It would indicate that complex organism did not evolve from simple organisms3 therefore the theory will be rejected3 OR It would mean that first protists and dinosaurs co-existed3 therefore dinosaurs did not evolve from protists3 (2) 3.5.4 Invertebrates have soft bodies3 which decay easily3/ do not fossilise OR Some invertebrates may have had an exoskeleton3 which decays easily3/ does not fossilise OR Earlier fossils of invertebrates3 might not yet have been discovered3 (2) (7) [30] TOTAL SECTION B: 60 Copyright reserved Please turn over ### Page 9 Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 9 DBE/Feb.–Mar. 2012 NSC – Memorandum SECTION C QUESTION 4 4.1 4.1.1 One3 (1) 4.1.2 Blood groups are controlled by three alleles3/ IA , IB , I which when in combination provide four phenotypes3/A, AB, B, O. (2) 4.1.3 Percentage distribution of blood groups in a province Blood group A Blood group O A O 35% 40% Blood group B Blood group AB AB B 10% 15% 10% 15% Blood group A: 35 x 360 100 1 = 126˚ Blood group B: 15 360 x 100 1 = 54˚ Blood group AB: 10 x 360 100 1 = 36˚ Blood group O: 40 360 x 100 1 = 144˚ Copyright reserved Please turn over ### Page 10 Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 10 DBE/Feb.–Mar. 2012 NSC – Memorandum Rubric for the mark allocation of the calculations Marks Calculations 1 1–3 correct 2 4 correct Rubric for the mark allocation of the pie chart Caption 1 Correct proportion of slices 1: 1–2 correct 2: 3–4 correct Label / key for each slice 1: 1 correct label 2: 2 correct label 3: 3–4 correct labels (8) NOTE: If the wrong type of illustration is drawn: marks will be lost for drawing the slices in correct proportions (11) 4.2 4.2.1 The average height 3of the plants decreases3 as the altitude3 increases3 OR The average height 3of the plants increases 3as the altitude3 decreases3 Max 3 (3) 4.2.2 All seeds from different altitudes were planted under the same environmental conditions3 Same number of seeds for each level was used3 (Mark first TWO only) (2) 4.2.3 - There is variation in the height of this plant population3/ some plants are tall and some are short - More short plants survived3 at high altitude to reproduce the next generation - Because the short plants are not easily broken by wind at high altitude3/ harsh environmental conditions at high altitude - Tall plants did not survive the strong winds/environmental conditions at high altitude3/ Fewer tall plants survived3 at high altitude Max 4 (4) (9) Copyright reserved Please turn over ### Page 11 Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 11 DBE/Feb.–Mar. 2012 NSC – Memorandum 4.3 Possible answer GENE MUTATIONS - Errors3/mistakes/changes may occur during transcription3/ DNA replication - Point mutations: replacing/substituting one base of a codon with another3 - Small change that may possibly result in one amino acid 3changing in a protein - Frame-shift mutations: addition/deletion of one or more bases of a codon3 - Resulting in changing the order/sequence of all the bases of the codons 3 - Resulting in forming a different protein3 with different functions3 - Lead to different phenotypes3 Max (6) MEIOSIS Crossing–over9 - Homologous chromosomes9/bivalents pair up - Each chromosome has 2 chromatids9 - Non-sister chromatids overlap/cross over9 - Points at which crossing-over takes place are referred to as chiasmata9 - Genetic material is exchanged9 between non-sister chromatids9 - After the process of crossing-over chromosomes have alleles from its homologous partner 9 -This means that each gamete formed will have a mix of alleles from both parents9 - Brings about variation in the gametes 9formed and also the offspring Max (7) Random arrangement of chromosomes 9at the equator - Each pair of homologous chromosomes 9may line up either way up on the equator of the spindle 9 - Independently of what the other pairs are doing9 -This means that gametes will have differing number/mix of both parental chromosomes 9 Max (4) (17) ASSESSING THE PRESENTATION OF THE ESSAY Marks Descriptions 3 Well structured – demonstrates insight and understanding of question 2 Minor gaps in the logic and flow of the answer 1 Attempted but with significant gaps in the logic and flow of the answer 0 Not attempted/nothing written other than question number Synthesis (3) (20) TOTAL SECTION C: 40 GRAND TOTAL: 150 Copyright reserved ## Related documents - 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