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PREPARATORY EXAMINATION GRADE 12 LIFE SCIENCES P2 SEPTEMBER 2016 MEMORANDUM MARKS: 150 This memorandum consists of 13 pages. Copyright reserved Please turn over Life Sciences P2 Grade 12 Prep. Exam. 2 Memorandum FS/September 2016 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 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 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. Copyright reserved Please turn over Life Sciences P2 Grade 12 Prep. Exam. 3 Memorandum FS/September 2016 13. If common names given in terminology Accept provided it was accepted at the memo discussion meeting. 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. Copyright reserved Please turn over Life Sciences P2 Grade 12 Prep. Exam. 4 Memorandum FS/September 2016 QUESTION 1 1.1.1 1.1.2 1.1.3 1.1.4 1.1.5 1.1.6 1.1.7 1.1.8 1.1.9 1.1.10 B C D B C A A C A C (10 x 2) 1.2.1 1.2.2 1.2.3 1.2.4 1.2.5 1.2.6 1.2.7 1.2.8 Dominant Hydrogen bond Chiasma Foramen magnum Population Chromatin network Nucleopores tRNA 1.3.1 1.3.2 1.3.3 B only A only B only (20) (8) (3 x 2) (6) 1.4.1 35 000 1.4.2 (a) Homo habilis (1) (b) Australopithecus africanus and Australopithecus afarensis (2) (c) Homo erectus (1) 1.4.3 Taung child Little foot Karabo Mrs Ples (Mark first ONE only) (1) Any 1 (1) (6) Copyright reserved Please turn over Life Sciences P2 Grade 12 Prep. Exam. 1.5.1 (a) (b) 1.5.2 5 Memorandum FS/September 2016 Smith's - Baby 3 (1) Jones' - Baby 2 (1) Solve crimes/criminal investigations Identify organisms from their tissues Identify family relationship Test for specific alleles that can cause a genetic disorder Establish matching tissues for organ transplants Used in research into variation in populations (Mark first THREE only) Any 3 (3) (5) 1.6.1 A B Spindle fibers (1) Centriole (1) 1.6.2 Metaphase II (1) 1.6.3 A – Pull chromosomes to poles/attachment of chromosomes C –Hold two chromatids together/attachment of spindle fibers (1) (1) (5) TOTAL SECTION A: 50 Copyright reserved Please turn over Life Sciences P2 Grade 12 Prep. Exam. 6 Memorandum FS/September 2016 QUESTION 2 2.1 2.1.1 (a) Ribosome (1) (b) tRNA (1) (c) translation (1) 2.1.2 The process is transcription* The double stranded DNA molecule unwinds/unzips When the hydrogen bonds break One strand is used as a template to form mRNA (no mark) Using free nucleotides from the nucleoplasm The mRNA is complementary to the DNA/A-U, C-G This process is controlled by enzymes *indicates a compulsory mark 1* *1+ Any (4) 2.1.3 Leucine, (Proline) Error on Paper + (2) 2.1.4 CAT 2.2 (1) (11) 2.2.1 Eyebrows not connected 2.2.2 - (5) (1) Parents A and B or C and D produce children with connected eyebrows and not connected eyebrows Only parents both carrying the dominant allele can produce offspring with both phenotypes OR - - Copyright reserved A and B or C and D have eyebrows that are not connected, produce a child with eyebrows which are connected then the allele for connected eyebrows was present in both parents, but masked, so eyebrows that are connected is recessive. Any (2) Please turn over Life Sciences P2 Grade 12 Prep. Exam. 2.2.3 Two fertilised eggs 2.2.4 - 2.2.5 2.3 7 Memorandum FS/September 2016 (1) One child is male and the other is female One child has eyebrows that are connected and the other has eyebrows that are not connected. 3/7 x 100 = 42,86% 2.3.1 - (2) (8) Her father had brown tooth enamel. Therefore his genotype must have been XbY. She could only inherit the recessive allelle Xb from her father. She had white teeth so she must have one dominant allele XB therefore she must be heterozygous. 2.3.2 P1/P2 Phenotype (2) Brown enamel Genotype x White enamel XbY x XBXb Y x XB , Meiosis G/gametes Xb , Fertilisation F1/F2 Genotype XBY, XbY, XBXb, XbXb (4) only 1 mark Xb Phenotype 1 white enamel son, 1 son with brown enamel 1 white enamel daughter, 1 daughter with brown enamel / 1:1:1:1 P1 and F1/P2 and F2 Meiosis and fertilisation 1 Compulsory + any 5 OR Copyright reserved Please turn over Life Sciences P2 Grade 12 Prep. Exam. P1 8 Memorandum Phenotype Genotype FS/September 2016 brown enamel XbY x white enamel x XBXb Gametes XB Xb Xb XBXb XbXb Meiosis Fertilisation Y XBY XbY 1 mark for correct gametes 1 mark for correct genotypes F1 Phenotype 1 son with white enamel, 1 son with brown enamel 1 daughter with white enamel, 1 daughter with brown enamel P1 and F1 Meiosis and fertilisation 1 Compulsory + any 6 2.4 2.4.1 Regulate chromosomal structure Regulate protein synthesis. /Regulate the quantity and quality of proteins made (Mark first TWO only) Any 2 - 2.4.2 95% 2.4.3 2.5 (6) (11) Contains sugar Contains the nitrogenous bases, Contains phosphate (Mark first THREE only) 2.5.1 (a) (b) (1) (3) (6) Bbll (1) White long hair (2) 2.5.2 BBLL Copyright reserved (2) (2) (4) [40] Please turn over Life Sciences P2 Grade 12 Prep. Exam. 9 Memorandum FS/September 2016 QUESTION 3 3.1 3.1.1 - stands higher to get a better view of the surroundings to search for food or spot predators free hands for hunting/to use tools, hold their young body cools faster/better thermo regulation movement became more efficient display of sex organs for courtship/attracting mate (Mark first TWO only) Any 2 (2) 3.1.2 3.1.3 3.1.4 freely rotating arms long upper arms elbow joints which allow rotation of forearms rotate hands flat nails instead of claws opposable thumbs 5 digits per limb (Mark first TWO only) Any 2 (2) Pelvis – from narrow & long wide and short and bowl shape holding the weight of the body making upright walking possible Allows for a bigger brain Development of speech/communication Higher intelligence Complex behaviour Quick processing of information Stores/Process large amounts of information (Mark first TWO only) 3.2 - Copyright reserved (4) Any 2 (2) (10) The boabab population has been separated into two groups by geographical barrier *sea/continental drift Environments on the continents may be different Each population undergoes natural selection independently and they become genotypically and phenotypically different This prevented them from interbreeding leading to the formation of new species. Any 6 (6) Geographical barrier/*compulsory mark Please turn over Life Sciences P2 Grade 12 Prep. Exam. 3.3 3.3.1 10 Memorandum Left-handers mirror writing are faster/slowly than righthanders. OR There is no difference in the speed of mirror quickly in leftand right-handers. 3.3.2 Left-handersor right-handers 3.3.3 Same age, gender/quality of insight/ mirror size/stopwatch/pen (2) (1) (First 2) (2) Left-handers speed in mirror is faster than right-handers (2) Time for mirror writing (seconds) 3.3.4 FS/September 2016 Left-handed Right-handed Mark allocation of the graph Criterion Elaboration Type of graph (T) Bar graph drawn Caption (C) Includes both variables: X-axis Equal width of bars AND correct label Y-axis Appropriate scale AND Correct label and units for Drawing of bars (P) 1-bars plotted correctly – 1 mark 2 bars plotted correctly – 2 marks NOTE: If axes are transposed: Marks will be lost for labelling of 'X-axis 'and 'Y-axis' Copyright reserved Mark 1 1 1 1 2 (6) (13) Please turn over Life Sciences P2 Grade 12 Prep. Exam. 3.4 3.4.1 3.4.2 3.4.3 Change in diet (vegetarian), larger body thicker tail longer tail longer toes bigger feet bigger bite force (Mark first THREE only) FS/September 2016 Any They do not need to move quickly to catch insects/plants are sedentary - Copyright reserved 11 Memorandum There is variation in the head size amongst wall lizards in the population some have large heads /bigger bite force and other have smaller heads /less bite force Insects became scares on the island /competition occurred for food Smaller head lizards that fed on insects struggled to obtain food and died of hunger While those with the larger heads fed on plants/ vegetation, had enough food to eat and survived Those with larger heads reproduce and pass the gene to the next generation Resulting in an increase in number in their population Any 6 (3) (2) (6) (9) Please turn over Life Sciences P2 Grade 12 Prep. Exam. 12 Memorandum FS/September 2016 SECTION C QUESTION 4 Selective breeding - E.g. farm animals, crops, dogs/(Any relevant example) Organisms of a species show variations Man selectsorganisms with traits which will be beneficial to him Interbreeds them with other organisms with the same desired characteristics to get the desired features Choose the offspring with the best combination of characteristics Allow them to breed with each other Repeat the process to improve the desired characteristics Max (5) + (1) for example (6) Similarities between natural selection, selective breeding and genetic engineering - They all involve the passing on of favourable characteristics There has to be genetic, inheritable differences All three processes lead to genotypic Phenotypic differences over time And can lead to formation of new species Max 3 (3) Differences between natural selection, selective breeding and genetic engineering Natural selection - Environmental conditions/pressure determine survival Organisms with less suitable characteristic die Organisms with more suitable survival of the best adapted No human intervention No cost involve Slow process that takes many generations Max 4 (4) Copyright reserved Life Sciences P2 Grade 12 Prep. Exam. 13 Memorandum FS/September 2016 Selective breeding and genetic engineering Characteristics that are desirable/beneficial to humansare being selected The characteristics are chosen by humans/It is an artificial process It is not necessarily beneficial for the organism Labour intensive May involve large costs Faster process Max 4 (4) Content: (17) Synthesis (3) (20) Criterion Relevance (R) In this Selective breeding essay example relevant and correct and only similarities and differences relevant to selective breeding, genetic engineering and natural selection is given. (There is no irrelevant information) Mark 1 Logical sequence (L) Selective breeding example discussed logically and only similarities and differences relevant to selective breeding, genetic engineering and natural selection is logical discussed 1 Comprehensive (C) Selective breeding example is discussed for a minimum of 4 marks similarities between the processes for 2 marks and differences between selective breeding, genetic engineering and natural selection for 6 marks. 1 TOTAL SECTION C: GRAND TOTAL: Copyright reserved 20 150 Please turn over