Life Sciences Grade 12 P2 Gauteng Mock 2015 Memo (English)

Downloaded from hlayiso.com PREPARATORY EXAMINATION 2015 MEMORANDUM SUBJECT: LIFE SCIENCES P2 (10832)

Downloaded from hlayiso.com 10832/15 GAUTENG DEPARTMENT OF EDUCATION PREPARATORY EXAMINATION – 2015 LIFE SCIENCES (Second Paper) MEMORANDUM PRINCIPLES RELATED TO THE MARKING OF 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 is incorrect, do not credit. If sequence and links becomes correct again, resume credit. 9. Non-recognized abbreviations Accept if first defined in the 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 recognizable accept the answer provided it does not mean something else in Life Sciences or if it is out of context. 1

Downloaded from hlayiso.com 10832/15 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. 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. Changes to the marking memorandum No changes must be made to the marking memoranda without consulting the Provincial Internal Moderator. 2

Downloaded from hlayiso.com 10832/15 SECTION A QUESTION 1 1.1 1.1.1 A 1.1.2 D 1.1.3 D 1.1.4 D 1.1.5 B 1.1.6 C 1.1.7 A 1.1.8 C 1.1.9 A (20) 1.1.10 B 1.2 1.2.1 DNA profiling  1.2.2 Gene  1.2.3 Genetic engineering/genetic manipulation 1.2.4 Punctuated equilibrium  1.2.5 Anaphase I  1.2.6 Non-disjunction  1.2.7 Chromosome  1.2.8 Species (8) 1.3 1.3.1 Both A and B 1.3.2 Both A and B 1.3.3 Both A and B 1.3.4 Both A and B 1.3.5 Both A and B 1.3.6 A only (12) 1.4 1.4.1 Between 2-3 weeks (2) 1.4.2 10000-1000 = 9000 (2) 1.4.3. 20 weeks (1) (5) 1.5 1.5.1 Africa (1) 1.5.2 Fossil record Mitochondrial DNA /genetic  (2) 1.5.3 Homo erectus (2) (5) TOTAL SECTION A: [50] 3

Downloaded from hlayiso.com 10832/15 QUESTION 2 2.1. 2.1.1 (DNA) replication  (1) 2.1.2. Interphase (1) A 2.1.3 – The DNA molecule unwinds and unzips – Template forms and nucleotides and bases pair up  – Two identical DNA molecules form and rewind to form a helix (3) (5) 2.2 2.2.1 - Decide on how the information will be gathered - Draw up a tool to collect data - Decide on a suitable time and venue - (Mark first TWO) (Any) (2) 2.2.2 - Ensure that the fingers are clean before taking prints to ensure no smudging occurs - Ensure that there is no duplication of prints from the same person (Mark first ONE) (Any 1x2) (2) 2.2.3 - Repeat the investigation - Increase the sample size of individuals in survey (2) 2.2.4 (a) Main types of fingerprints  (1) (b) Number of learners  (1) (c) Rejected– most learners in sample had plain whorl fingerprints (2) (10) 2.3. 2.3.1 Australopithecus afarensis (1) 2.3.2 0,8 million yrs ago (MYA) (1) 2.3.3 MODEL 1 MODEL 2 A. afarensis is the common H. ergaster is the common ancestor for H. erectus ancestor for H. erectus A. afarensis is the common A. africanus is a common (5) ancestor for H. habilis ancestor for H. habilis + (table) 2.3.4 It has bothcharacteristics of Austraopithecus and Homo species (1) 2.3.5 - Mrs Ples - Tuang child - Little foot - Karabo(Any TWO) (2) (10) 4

Downloaded from hlayiso.com 10832/15 2.4 2.4.1 Mitosisit is a somatic cell / diploid (2) 2.4.2 It is haploidand does not have desirable genes (1) 2.4.3 Fertilisation was manipulated by scientists/not naturally fertilised (1) 2.4.4 - Cannot play God/ religious objection - May result in harmful mutations/ we don’t know about long term effects - May result in the loss of biodiversity (1) (5) 2.5 2.5.1 (a) RRGG (1) (b) rrgg (1) 2.5.2 RG, RG, RG, RG/all RG /RG (2) 2.5.3 (a) Black eyes, grey tailfeathers  (1) (b) Red eye, grey tailfeathers (1) (6) 2.6 2.6.1 Continuous variation is characterised by range of intermediate phenotypes resulting in histograms (2) 2.6.2 Discontinuous variation is characterised by unique phenotypes resulting in bar graphs (2) (4) [40] 5

Downloaded from hlayiso.com 10832/15 QUESTION 3 3.1 3.1.1 - There is variation in the length of the trunks among the elephants - The elephants with the long trunks have the desirable characteristic/ long trunks can easily scoop water and grasp leaves from trees/for surviving under unfavourable or dry conditions - More of the elephants with long trunks survive - Most of the elephants with the short trunks die - Long-trunked elephants reproduce and - produce offsprings with long trunks (any 6) (6) 3.1.2 - Law of use and disuse - Inheritance of acquired characteristics (2) (8) 3.2 3.2.1 Walkingon two feet (2) 3.2.2 -Detect danger/predators easily due to being taller -Can carry their young/food as both hands are free (4) 3.2.3 - The bigger/wider/broader pelvis ensures that the attachment of the limbs is better spread - The shorterpelvis allows body to be balanced and held upright. (4) (10) 3.3 3.3.1 A (1) + table 3.3.2 A B Cranium is smaller/ has a Cranium is larger/ more ridge rounded Brow ridges more Brow ridges less pronounced pronounced (5) 3.3.3. - The jaws were prognathous/more pronounced to provide strength - Brow ridges were more pronounced  to provide strength in the chewing action - The well developed zygomatic arch provides support / strength for the muscles involved in chewing - Well developed incisors  for cutting fibrous food (any 1x2) (2) (8) 6

Downloaded from hlayiso.com 10832/15 3.4 3.4.1 (a) Normal male  (1) (b) XDY (2) 3.4.2 Both alleles are carried on the sex chromosomes (1) 3.4.3 - - Colour blindness is carried by a recessive allele - - On the X-chromosome - - Females have two X chromosomes/ Males have only one X - chromosome - - Females must inherit two copies of the recessive allele - to show the disorder / females who inherit only one of the recessive (3) - allele are still normal (any 3) 3.4.4 P1/P3 Phenotype Colour blind female x Normal male female Genotype XdXd x XDY Meiosis  G/gametes Xd, Xd XD, Y  Fertilisation F1/F3 Genotype XDXd;; XdY; XDXd XdY Phenotype 2 normal daughters : 2 colour blind sons *50% chance of having a colour blind son P1 and F1 Meiosis and fertilisation *1 compulsory +any 6 OR P1/P3 Phenotype colour blind female x Normal female  Genotype XdXd x XDY Meiosis Gametes Xd Xd Fertilisation XD XDXd XDXd Y XdY XdY 1 mark for correct gametes 1 mark for correct genotypes F1/F3 Phenotype 2 normal daughters : 2 colour blind sons *50% chance of having a colour blind son P1 and F1 Meiosis and fertilisation *1 compulsory+any 6 (7) (14) [40] 7

Downloaded from hlayiso.com 10832/15 SECTION C QUESTION 4 TRANSCRIPTION - The double stranded DNA molecule unwinds/unzips - When the hydrogen bonds break - One strand is used as a template - to form mRNA  - Using free nucleotides from the nucleoplasm - The mRNA is complementary to the DNA/A-U, C-G - This process is controlled by enzymes - this process is called transcription (max 6) (6) TRANSLATION - mRNA moves out of nucleus  - through nuclear pore into cytoplasm - and attaches itself to ribosome - The three adjacent bases on mRNA known as codons - according to the codons on the mRNA - tRNA molecules with matching complementary anticodons - bring the required amino acids to the ribosome - Amino acids link together by peptide bonds to form a protein - This process is called translation. (max 7) (7) Definition of mutation Change in the sequence of nitrogen bases brings about a change in the gene composition  and blood would not clot/absence of blood clotting factors resulting in haemophilia - or absence of pigmentation/no melanin resulting in albinism - absence of proteins - that comprise either for red and green cones/ photoreceptors - in the eye resulting in colour blindness (max 4) (4) Content: (17) Synthesis: (3) (20) ASSESSING THE PRESENTATION OF THE ESSAY Criterion Relevance (R) Logical sequence (L) Comprehensive (C) Generally All information provided is Ideas are arranged in a logical All aspects required by the relevant to the topic sequence for each process essay have been sufficiently addressed In this Only information relevant Information regarding protein At least three correct essay to protein synthesis, synthesis, mutations, points on transcription, mutations, haemophilia haemophilia, albinism and translation and mutations ,albinism and colour blindness arranged in a colourblindness is given logical way Mark 1 1 1 TOTAL SECTION C: 20 GRAND TOTAL: 150 8