Life Sciences Grade 12 P1 NSC November 2012 Memo (English)

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE GRADE 12 LIFE SCIENCES P1 VERSION 1 (NEW CONTENT) FOR FULL-TIME CANDIDATES NOVEMBER 2012 FINAL MEMORANDUM MARKS: 150 This memorandum consists of 12 pages. Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 2 DBE/November 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-recognized 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 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

Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 3 DBE/November 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, drawings, 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. Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 4 DBE/November 2012 NSC – Memorandum SECTION A QUESTION 1 1.1 1.1.1 D 1.1.2 C 1.1.3 B  1.1.4 C 1.1.5 C 1.1.6 C 1.1.7 C 1.1.8 D 1.1.9 B 1.1.10 C (10 x 2) (20) 1.2 1.2.1 Sympatricspeciation 1.2.2 Non-disjunction/(non-separation) 1.2.3 Homozygous 1.2.4 Polyploidy 1.2.5 Homologousstructure 1.2.6 Nucleotides 1.2.7 Cytokinesis 1.2.8 Replication (8) 1.3 1.3.1 Both A and B 1.3.2 A only 1.3.3 Both A and B 1.3.4 Both A and B 1.3.5 B only 1.3.6 Both A and B 1.3.7 B only 1.3.8 None (8 x 2) (16) 1.4 1.4.1 C- deoxyribose/(sugar) D- phosphate (2) 1.4.2 (weak) hydrogen bond (1) 1.4.3 It is doublestranded/base pairs are present/(ladder -like) (1) (Mark first ONE only) 1.4.4 nucleus/chromosomes/chromatin/mitochondrion (2) (6) TOTAL SECTION A: 50 Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 5 DBE/November 2012 NSC – Memorandum SECTION B QUESTION 2 2.1 2.1.1 X - chiasma Z - centromere (2) 2.1.2 The chromosomes are of the same structure / size/ shape/ length Crossing-over is taking place any (1) (Mark first ONE only) 2.1.3 It increases genetic variation/produces recombinant gametes (1) (Mark first ONE only) 2.1.4 Random arrangement of chromosomes /independent assortment (1) (Mark first ONE only) 2.1.5 40/20 pairs (1) (6) 2.2 2.2.1 (a) 21 (b) 6 (c) 7 (3) 2.2.2 ACU CCU GAG (sequence must be correct) (3) 2.2.3 threonine prolineglutamate (sequence must be correct) (3) 2.2.4 (a) valine (b) pointmutation (2) 2.2.5 Sickle-shaped red blood cells would carry less O 2  to cells therefore less cellular respirationleading to less energy being generated/tiredness/lethargy/fatigue OR Sickle-shaped red blood corpuscles blocks small blood vesselswhich leads to reduced blood supply/reduced O 2 therefore less cellular respiration leading to less energy being generated/tiredness/ fatigue/lethargy/damage to organs OR May prevent malaria because the parasite does not survive if it invades sickle- shaped red blood corpuscles (3) (14) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 6 DBE/November 2012 NSC – Memorandum 2.3 2.3.1 White (1) 2.3.2 Genetic cross 2 (1) (Mark first ONE only) 2.3.3 Greater proportion of plants had white corn/ 3 white : 1 yellow OR Yellow appeared in offspring yet not in parents showing that yellow is recessive/white is dominant (2) 2.3.4 P 1 /parent phenotype white maize x white maize genotype Gg x Gg Meiosis G/gametes G, g x G, g Fertilisation F 1 /offspring genotype GG, Gg, Gg & gg phenotype 3 white and 1 yellow maize Generations: Parents/P 1 and offspring /F 1  Processes: Meiosis and fertilisation any (6) OR P 1 /parent phenotype white maize x white maize genotype Gg x Gg  Meiosis Fertilisation gametes G g G GG Gg g Gg gg 1 mark for correct gametes 1 mark for correct genotypes F 1 /offspring phenotype 3 white and 1 yellow maize Generations: Parents/P 1 and offspring /F 1  Processes: Meiosis and fertilisation any (6) (10) [30] Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 7 DBE/November 2012 NSC – Memorandum QUESTION 3 3.1 3.1.1 4 (1) 3.1.2 The allele for the trait is carried on the X-chromosome/ Y chromosome does not carry the allele for the trait. Male only has one X chromosome A male needs only one recessive allele to be haemophiliac Whereas for a female to be haemophiliac both alleles must be recessive any (3) 3.1.3 (a) XH Xh (2) (b) XhY (2) 3.1.4 25% / ¼ OR 50% / ½ (2) 3.1.5 To determine if the wife is a carrier To determine the chances of having a child with haemophilia Help them evaluate whether they would cope with such a child Help them make an informed decision about whether to have children  any (2) (Mark first TWO only) (12) 3.2 3.2.1 To increase the reliability of the results (1) 3.2.2 1:1/(90:90) (1) 3.2.3 In a DNA molecule, thymine always pairs with adenine/thymine and adenine are complementary bases (1) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 8 DBE/November 2012 NSC – Memorandum 3.2.4 º º º 29 x 360 = 104,4 /104 100 º º º 31 x 360 = 111,6 /112 100  º º º 21 x 360 = 75,6 /76 100 º º º 19 x 360 = 68,4 /68 100  Type Percentage of each DNA nucleotide (in sample 1)  Title   Adenine Thymine Cytosine  Guanine  Mark allocation of the graph Calculations/working to determine the 2 marks: All four calculations correct correct proportions 1 mark: 1 to 3 calculations correct Correct type of graph (pie chart) 1 Title of graph 1 Proportions accurate for each 4 marks: All four sectors correct (use sector/slice labelled /key transparency template) (1 x mark/ sector) (8) (11) Note: If the wrong type of graph is drawn: marks will be lost for 'correct type of graph' as well as for 'drawing of sectors in correct proportion'. Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 9 DBE/November 2012 NSC – Memorandum 3.3 3.3.1 (a) New equipment/research is expensive Labour intensive Many clinical trialsmust be done/long time to produce a safe product any (2) (Mark first TWO only) (b) May easily pollinate/mate with non-GM crops/animals They might out-compete/destroy the naturally occurring organisms Reduces gene pool/variation May not be a suitable food source anymore for other organisms GMO may be poorly adapted to environment any (2) (Mark first TWO only) 3.3.2 Interfering with nature Immoral/ we cannot play God Violation of natural organism's intrinsic value Unsure of long term effects Potential health risk Domination of world food production by only a few companies (Mark first THREE only) any (3) (7) [30] TOTAL SECTION B: 60 Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 10 DBE/November 2012 NSC – Memorandum SECTION C QUESTION 4 4.1 4.1.1 Carefully analyse and verify the evidence/findings before releasing the results (2) 4.1.2 To inform people of their findings so that they can critique/verify their findings/use it for future research/acknowledge ownership of the findings (2) 4.1.3 A transitional form has characteristics of both the australopithecines and humans (2) 4.1.4 The brain was small like other Australopithecine species but the re-organisation/configuration of the brain/an expansion behind and above the eyes was more like modern humans OR Brain/hand/foot have characteristics of both modern and early pre-human (Mark first ONE only) (2) 4.1.5 Olfactory brain centres reduced/reduced sense of smell Eyes in front Binocular vision /stereoscopic vision Eyes with cones/colour vision Freely rotating arms Elbow joints allowing rotation of forearm Flat nails instead of claws/bare, sensitive finger tips Opposable thumbs Upright posture/bipedal Sexual dimorphism Long upper arms Two teats 5 Fingers Fewer offspring any (6) (Mark first SIX only) (14) 4.2 4.2.1 Palaeomastodon sp.  (1) 4.2.2 Elephas sp. Loxondonta sp. (2) (Mark first TWO only) 4.2.3 Primelaphus sp. (1) 4.2.4 (a) Miocene (b) Pleistocene (2) (6) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 11 DBE/November 2012 NSC – Memorandum 4.3 Natural selection e.g. Finches*/or any other example - Organisms of a particular species shows a great deal of variation - Some individuals may have characteristics /any example that are favourable /some individuals may be adapted to the environment - Others may have characteristics/any example that are unfavourable - Selective pressure by the environment due to competition/changing environmental conditions - Organisms with favourable characteristics survive and reproduce - to pass favourable characteristics to their offspring - while organisms with unfavourable characteristics will die out - Over time the whole population will have this favourable trait - Over time these organisms might develop genotypically and phenotypically independently - into different species which cannot interbreed *Compulsory mark Max 7 + 1 for example* (8) Artificial selection e.g. Production of improved fruit/ meat production* - Organisms of a particular species/any example show a great deal of variation - Humans select organisms - with a particular desirable characteristic - and interbreedthem - with other organisms that also have the same desirable characteristic - to improve this characteristic further in the offspring - They may also choose organisms with different desirable characteristics - to get offspring with a combination of these desirable characteristics *Compulsory mark Max 4 + 1 for example* Differences between Natural and Artificial selection (5) Natural selection Artificial selection Selective pressure by the environment Humans select the desirable characteristic Selection is in response to suitability to Selection is in response to satisfying human the environment needs Organisms can survive on their own in Organisms may often not survive on their the environment (since they were own in the environment (since they were selected on the basis of their suitability to selected on the basis of human needs and the environment) not on suitability to the environment) No human effort/cost involved Could be labour intensive/expensive any 2x2 (4) Content (17) Synthesis (3) (20) ASSESSING THE PRESENTATION OF THE ESSAY Marks Description 3 Well structured- demonstrate insight and understanding of question 2 Minor gaps or irrelevant information in the logic and flow of the answers 1 Attempted but with significant gaps and irrelevant information in the logic and flow of the answers 0 Not attempted/nothing written other than question number/no correct information TOTAL SECTION C: 40 GRAND TOTAL: 150 Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P1 (Version 1) (Full-time) 12 DBE/November 2012 NSC – Memorandum Percentage of each DNA nucleotide (in sample 1)  Title  Type G A C  T sectors Percentage of each DNA nucleotide (in sample 1)  Title  Type G A C  T sectors Percentage of each DNA nucleotide (in sample 1)  Title  Type G A C  T sectors Copyright reserved Please turn over