Life Sciences Grade 12 Paper 2 North West Mock 2019 Memo

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE GRADE 12 LIFE SCIENCES P2 SEPTEMBER 2019 MARKING GUIDELINES MARKS: 150 These marking guidelines consists of 13 pages and a cognitive grid of 5 pages Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 2 NW/September 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 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 are 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 unrecognised 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 recognisable 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 memo discussion meeting. Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 3 NW/September 2019 NSC-Marking Guidelines 14. If only the letter is asked for, and 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 marking memoranda without consulting the provincial internal moderator. Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 4 NW/September 2019 NSC-Marking Guidelines SECTION A QUESTION 1 1.1 1.1.1 B 1.1.2 D 1.1.3 A 1.1.4 B 1.1.5 C 1.1.6 A 1.1.7 C 1.1.8 B 1.1.9 C 1.1.10 A (10 x 2) (20) 1.2 1.2.1 Allele 1.2.2 Gene 1.2.3 Centromere  1.2.4 Anaphase I 1.2.5 Haploid  1.2.6 Colour blindness (6) 1.3 1.3.1 A only 1.3.2 B only 1.3.3 A only  (3 x 2) (6) 1.4 1.4.1 47 (1) 1.4.2 Down syndrome (1) 1.4.3 Autosomes (1) 1.4.4 Female (1) 1.4.5 Chromosome pair 23/gonosomes XX (1) 1.4.6 Non-disjunction (1) (6) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 5 NW/September 2019 NSC-Marking Guidelines 1.5 1.5.1 Cloning (1) 1.5.2 (a) A (1) (b) C (1) 1.5.3 (a) 4 (1) (b) 5 6 (2) (Mark first TWO only) 1.5.4 Bone marrow Umbilical cord Amniotic fluid (2) (Mark first TWO only) (8) 1.6 1.6.1 (a) F (1) (b) D (1) (c) E/A (1) (d) C (1) (4) TOTAL SECTION A: 50 Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 6 NW/September 2019 NSC-Marking Guidelines SECTION B QUESTION 2 2.1 2.1.1 (a) DNA (1) (b) mRNA (1) 2.1.2 CGT (2) 2.1.3 GCA (2) 2.1.4 Translation - Each tRNA carries a specific amino acid - When the anticodon on the tRNA - matches the codon on the mRNA - then tRNA brings the required amino acid to the ribosome - Amino acids become attached by peptide bonds - to form the required protein Any (5) (11) 2.2 2.2.1 The sudden, random change in the genetic code of a cell (1) 2.2.2 Gene mutation (1) 2.2.3 - Gene mutation affect a single or a few base pairs in the single gene - the base sequence CCT is changed to CAT - which produces a different polypeptide Any (2) 2.2.4 (a) Glutamic acid (1) (b) Valine (1) 2.2.5 - The two strands would not separate - The DNA will not replicate - and protein synthesis will not take place Any (2) (8) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 7 NW/September 2019 NSC-Marking Guidelines 2.3 2.3.1 Cell membrane (1) 2.3.2 - To contract and pull the chromosomes to the poles - To hold the chromosomes / facilitates the attachment of the centromere  (Mark first ONE only) (1) 2.3.3 Metaphase II (1) 2.3.4 - Chromosomes are aligned in a single row - on the equator (2) 2.3.5 Crossing over Random arrangement of chromosomes Any (1) (6) 2.4 2.4.1 (a) BbNn (1) (b) bbnn (1) 2.4.2 BN, Bn, bN, bn  (All or none) (2) 2.4.3 (a) Bitter fruit with no spots (1) (b) Sweet fruit with yellow spots (1) (6) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 8 NW/September 2019 NSC-Marking Guidelines 2.5.1 - The parents have the dominant phenotype/have one dominant allele - To have children with the recessive characteristic/bb - The other allele of each parent must be recessive/ b (3) 2.5.2 P1/parent Phenotype Bent little x Straight little fingers fingers Genotype Bb x bb  Meiosis G/gametes B, b x b; b Fertilisation F1 Genotype Bb ; Bb ; bb ; bb Phenotype 2 Bent little fingers, 2 straight little fingers * Parents and offspring/P1 and F1 Meiosis and fertilisation (*compulsory mark + 5) OR P1/parent Phenotype Bent little x Straight little fingers fingers Genotype Bb x bb Meiosis G/gametes B, b x b, b  Gametes b b B Bb Bb Fertilisation b bb bb Correct genotypes  F1 Phenotype 2 bent little fingers, 2 straight little fingers * Parents and offspring/P1 and F1 (6) Meiosis and fertilisation (* compulsory mark + 5) (9) [40] Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 9 NW/September 2019 NSC-Marking Guidelines QUESTION 3 3.1 3.1.1 Ceratotherium (1) 3.1.2 - Ancestors of rhinos had very small horns - Due to the need for clearing bush/to fight with other rhinos to get mating partners, - the horns become stronger/overuse - Over time the horns would grow longer/stronger in a single rhino’s lifetime - - This trait is inherited to the next generation Any (4) (5) 3.2 3.2.1 Genetic engineering/ genetic modification/artificial selection (1) 3.2.2 - Taller plants - Having shorter life cycle - Greater yield - Able to grow in rich aluminium soil - More competitive with weeds (3) (Mark first THREE only) 3.2.3 - Expensive - Reducing variation - Health risk Any (2) (Mark first TWO only) (6) 3.3 3.3.1 - The original shrimp population was separated into two different populations - by land bridge Panama/Caribbean sea and Pacific ocean - which acted as a geographical barrier - There was no gene flow between the populations - Each population was exposed to different environmental conditions - Natural selection occurred independently in each population - and individuals of each population became different over time - genotypically and phenotypically - Even if the two populations were to mix again - they would not be able to interbreed The two populations are now different species Any (6) 3.3.2 Continental drift (1) (7) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 10 NW/September 2019 NSC-Marking Guidelines 3.4 3.4.1 (a) Colour of the rock rabbits (1) (b) Survival rate of the rock rabbits (1) 3.4.2 - It decreases survival/rock rabbits may die / is harmful / is lethal to the white rock rabbits/rock rabbits may become extinct - They will be seenon the black rock by the predators OR - They could not escape predators - as white rock rabbits did not warm up fast on cold days Any (2) 3.4.3 - To allow enough time for reproduction and survival - To be able to calculate the percentage to ensure reliability of results OR - A change in population proportions will not be seen over a shorter time period - To ensure reliability of results. Any (2) 3.4.4 - Rock rabbits must be of the same size/age - Conducted the investigation in the same habitat/ environment - Used the same sampling technique - Captured the same number of rock rabbits in each sampled generation - Took each sample at the same time of the day - Weather conditions should have been the same (1) (Mark first ONE only) 3.4.5 - There is variation to colour amongst the rock rabbits - White and brown rock rabbits - are not camouflaged / cannot warm up fast enough to have energy to run away - Are killed by predators - The black rock rabbits - are better camouflaged/ warm up faster to have energy to avoid predators - and survived/ reproduced - The allele for black colour is passed on to the next generation . Any (6) (13) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 11 NW/September 2019 NSC-Marking Guidelines 3.5 3.5.1 Homo habilis (1) 3.5.2 - Genetic/mitochondrial DNA - Cultural (Mark first TWO only) (2) 3.5.3 Ardipithecus ramidus (1) 3.5.4 (1400 - 500) = 900cm3 (2) 3.5.5 There is an overlap in their period of existence/they both (1) existed between 2 and 1,6 mya 3.5.6 - They would measure the volume - of the craniumof the fossil (2) (9) [40] TOTAL SECTION B: 80 Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 12 NW/September 2019 NSC-Marking Guidelines SECTION C QUESTION 4 Trend towards bipedalism (B) Foramen magnum, curvature of the spine and pelvic girdle - The foramen magnum was in a backward position in the ape-like beings - but in a forward position in modern humans - Modern humans have a more curved / S-shaped spine - for better balance - Ape-like beings have a less curved/ C-shaped spine - Modern humans have a short wide pelvis/cup shaped pelvis - which makes it suitable to carry the core of the body - whereas ape-like beings have a long, narrow pelvis - Decrease in length of arms in humans indicates - decreased dependency on its use in locomotion - and therefore shows a more advanced stage of bipedalism Any 8 (8) Change in diet from raw food to cooked food (D) Prognathism, Dentition/teeth, shape of palate - Humans have jaws that are non-prognathous/ flat face for eating cooked food - compared to the jaws of ape-like beings which are prognathous/sloping face for scooping the food/ to reduce dependency on arms - Brow ridges became less developed in humans - since the action of smaller jaws did not create forces great enough for skull to have increased strength from the brow ridges - Ape-like beings have stronger jaws - to break and chew raw food - Absence of gaps(diastema) in humans between incisors and canines - indicating diet that is more refined - Humans have smaller teeth/incisors and canines - and flatter molars and pre-molarsfor better chewing - compared to long and rectangular palates of ape-like beings Any 9 (9) Content: (17) Synthesis: (3) (20) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 13 NW/September 2019 NSC-Marking Guidelines ASSESSING THE PRESENTATION OF THE ESSAY Logical Criterion Relevance (R) Comprehensive (C) sequence (L) Generally All information provided is Ideas are Answered all aspects relevant to the topic arranged in a required by the essay in logical/cause- sufficient detail effect sequence In this Only information relevant All the information At least the following essay in to trend towards regarding the: points should be Q4 bipedalism and change in - Bipedalism included: diet from raw to cooked and food are discussed. - Change in diet - Bipedalism (5/8) is arranged in - Change in diet (6/9) There is no irrelevant a logical information manner Mark 1 1 1 TOTAL SECTION C: 20 GRAND TOTAL: 150 Copyright reserved Please turn over

Life Sciences/P2 Downloaded from hlayiso.com 14 NW/September 2019 NSC-Marking Guidelines Life Sciences P2 September Prep 2019 Analysis Grid Question Topic A B C D DNA Meiosis Genetics Evolution Basic Comprehension Application Analysis, code of Knowledge Synthesis, life Evaluation 1.1.1 DNA nucleotide 2 2 1.1.2 Characteristics of tRNA 2 2 1.1.3 Blood group 2 2 1.1.4 Mutation 2 2 1.1.5 DNA % of Guanine 2 2 1.1.6 Order of evolution 2 2 1.1.7 Isolating mechanisms 2 2 1.1.8 Co-dominance 2 2 1.1.9 Punctated equilibrium 2 2 1.1.10 DNA profile 2 2 TOTAL 12 4 2 2 8 0 6 6 1.2.1 Allele 1 1 1.2.2 Gene 1 1 1.2.3 Centromere 1 1 1.2.4 Anaphase I 1 1 1.2.5 Haploid 1 1 1.2.6 Colour blindness 1 1 TOTAL 6 0 0 0 0 2 4 0 1.3.1 A only 2 2 1.3.2 B only 2 2 1.3.3 A only 2 2 TOTAL 0 6 0 0 0 0 6 0 1.4.1 47 chromosomes 1 1 Copyright reserved

Life Sciences/P2 Downloaded from hlayiso.com 15 NW/September 2019 NSC-Marking Guidelines Life Sciences P2 September Prep 2019 Analysis Grid Question Topic A B C D DNA Meiosis Genetics Evolution Basic Comprehension Application Analysis, code of Knowledge Synthesis, life Evaluation 1.4.2 Down syndrome 1 1 1.4.3 Autosomes 1 1 1.4.4 Female 1 1 1.4.5 Reason for a female 1 1 1.4.6 Non-disjunction 1 1 TOTAL 5 1 0 0 0 2 4 0 1.5.1 Cloning 1 1 1.5.2 A, C 2 2 1.5.3 (a) 4 1 1 1.5.4 (b) 5, 6 2 2 Umbilical cord, bone 2 2 1.5.5 marrow TOTAL 6 2 0 0 0 0 8 0 1.6.1 (a) F 1 1 (b) D 1 1 (c) E 1 1 (d) C 1 1 TOTAL 0 4 0 0 0 4 0 0 TOT Q 1 29 17 2 2 8 6 30 6 2.1.1 DNA & mRNA 2 2 2.1.2 DNA genetic codes 2 2 2.1.3 Anticodons 2 2 Copyright reserved

Life Sciences/P2 Downloaded from hlayiso.com 16 NW/September 2019 NSC-Marking Guidelines Life Sciences P2 September Prep 2019 Analysis Grid Question Topic A B C D DNA Meiosis Genetics Evolution Basic Comprehension Application Analysis, code of Knowledge Synthesis, life Evaluation 2.1.4 Describe translation 5 5 TOTAL 7 0 4 0 11 0 0 0 2.2.1 Definition mutation 1 1 2.2.2 Gene mutation 1 1 2.2.3 Explanation for a gene 2 2 mutation 2.2.4 Glutamic acid, Valine 2 2 DNA replication would 2 2 2.2.5 not TOTAL 4 0 2 2 8 0 0 0 2.3.1 Cell membrane 1 1 2.3.2 To pull the 1 1 chromosomes to the poles 2.3.3 Metaphase II 1 1 2.3.4 Explanation for 2.3.3 2 2 2.3.5 Crossing over 1 1 TOTAL 6 0 0 0 0 6 0 0 2.4.1 Genotype of A and B 2 2 Genotype of all 2 2 2.4.2 gametes Phenotype of Bbnn, 2 2 2.4.3 bbNN TOTAL 0 2 4 0 0 0 6 0 Copyright reserved

Life Sciences/P2 Downloaded from hlayiso.com 17 NW/September 2019 NSC-Marking Guidelines Life Sciences P2 September Prep 2019 Analysis Grid Question Topic A B C D DNA Meiosis Genetics Evolution Basic Comprehension Application Analysis, code of Knowledge Synthesis, life Evaluation 2.5.1 Explanation A and B 3 3 are heterozygous 2.5.2 Drawing of a genetic 6 6 cross TOTAL 0 0 6 3 0 0 9 0 TOT Q2 17 2 16 5 19 6 15 0 3.1.1 Ceratotherium 1 1 3.1.2 Lamarck and rhino horn 4 4 TOTAL 1 0 0 4 0 0 0 5 3.2.1 Genetic engineering 1 1 3.2.2 Advantages 3 3 3.2.3 Disadvantages 2 2 TOTAL 4 0 2 0 0 0 0 6 3.3.1 Speciation of shrimp 6 6 3.3.2 Continental drift 1 1 TOTAL 1 0 6 0 0 0 0 7 3.4.1 Variables 2 2 3.4.2 Effect of mutation on 2 2 survival 3.4.3 For reliability 2 2 3.4.4 Validity 1 1 Explain natural 6 6 3.4.5 selection Copyright reserved

Life Sciences/P2 Downloaded from hlayiso.com 18 NW/September 2019 NSC-Marking Guidelines Life Sciences P2 September Prep 2019 Analysis Grid Question Topic A B C D DNA Meiosis Genetics Evolution Basic Comprehension Application Analysis, code of Knowledge Synthesis, life Evaluation TOTAL 0 6 0 7 0 0 0 13 3.5.1 Brain volume 1 1 3.5.2 Evidence for evolution 2 2 3.5.3 Extinction 1 1 3.5.4 Calculation 2 2 3.5.5 Australopithecus 1 1 3.5.6 Brain volume 2 1 TOTAL 3 4 2 0 0 0 0 9 TOT Q3 9 10 10 11 0 0 0 40 TOT Q4 Essay 0 8 9 3 0 0 0 20 Q1 29 17 2 2 8 6 30 6 Q2 17 2 16 5 19 6 15 0 Q3 9 10 10 11 0 0 0 40 Q4 0 8 9 3 0 0 0 20 MARKS 55 37 37 21 27 12 45 66 % 37.0 25.0 25.0 14.0 18.0 8.0 30.0 44.0 NORM 60 38 30 22 27 12 45 66 MARKS NORM % 40 25 20 15 18 8 30 44 Copyright reserved