Life Sciences Grade 12 P2 Eastern Cape Mock 2015 Memo (Eng)

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE GRADE 12 SEPTEMBER 2015 LIFE SCIENCES P2 MEMORANDUM MARKS: 150 This memorandum consists of 9 pages.

Downloaded from hlayiso.com 2 LIFE SCIENCES P2 (EC/SEPTEMBER 2015) SECTION A QUESTION 1 1.1 1.1.1 A  1.1.2 C  1.1.3 A  1.1.4 D  1.1.5 C  1.1.6 A  1.1.7 A  1.1.8 D  1.1.9 D  1.1.10 B  (10 x 2) (20) 1.2 1.2.1 Protein  1.2.2 tRNA  / transfer RNA 1.2.3 Hydrogen bond  1.2.4 Punctuated equilibrium  1.2.5 Ribosome  1.2.6 Uracil  1.2.7 Transcription  1.2.8 Ribose  (8 x 1) (8) 1.3 1.3.1 A only  1.3.2 B only  1.3.3 B only  1.3.4 A only  1.3.5 A only  1.3.6 Both A and B  (6 x 2) (12) 1.4 1.4.1 A diagrammatic representation  showing the relationship among different species.  (2) 1.4.2 Australopithecus afarensis  (1) 1.4.3 Homo sapiens  / modern man (1) 1.4.4 Australopithecus africanus,  Homo habilis,  Homo erectus  (Any 2 x 1) (2) 1.4.5 (2,0  – 0,5 ) = 1,5 million years ago (Accept 1.8 and 1.9 for Homo erectus) (3) 1.4.6 Homo erectus  (1) TOTAL SECTION A: 50 Copyright reserved Please turn over

Downloaded from hlayiso.com (EC/SEPTEMBER 2015) LIFE SCIENCES P2 3 SECTION B QUESTION 2 2.1 2.1.1 Metaphase I – chromosomes come as homologous pairs to the equator Metaphase II – individual chromosomes to the equator  (1) 2.1.2 18 min  (1) 2.1.3 (28 min – 18 min) = 10 min  (2) 2.2 2.2.1 It refers to all the DNA  in an organism including its genes.  (2) 2.2.2 It is a section of DNA with a specific sequence of bases  that acts as the instructions for producing a specific protein.  (2) 2.2.3 Regulate chromosomal structure.  Regulate protein synthesis. / Regulate the quantity and quality of proteins made. (2) 2.2.4 (a) 95%  (1) (b) It is made of repeated sequence/non-coding regions and its function is not known.  (1) 2.2.5 Number of genes on the other chromosomes = 24 000  – (2 965 + 231)  = 20 804  genes OR = 24 000  – 3 196  = 20 804  genes (3) 2.3 2.3.1 A – chromosome  B – centromere  C – chromatid  D – chiasma /chiasmata (4) 2.3.2 Crossing over  (1) 2.3.3 It introduces genetic  variation.  (2) 2.3.4 CHROMOSOME AFTER CROSSING OVER A double stranded chromosome / Strands joined by a centromere Evidence of crossing over shown  Heading  (3) Copyright reserved Pleaseturn Please turnover over

Downloaded from hlayiso.com 4 LIFE SCIENCES P2 (EC/SEPTEMBER 2015) 2.4 2.4.1 It transports amino acid / lysine to the mRNA.  UUC (anticodon) joins with AAG (codon) on mRNA.  Amino acid / lysine (on the tRNA) form a peptide bond with the polypeptide chain  to form a protein. tRNA is now free to return to cytoplasm (to join with other lysine / amino acid).  (Any 3 x 1) (3) 2.5 2.5.1 Large number of eggs produce , therefore improves reliability  simple nutrient medium  therefore reduces costs  markings on male/size of female therefore easy to identify  short generation time  therefore results obtained quickly  (Any 2 x 2) (4) 2.5.2 P1 Phenotype White eyed male X Red eyed female Genotype Xr Y X XR XR  Meiosis   Gametes Xr ; Y XR ; XR  Fertilisation F1 Genotype XP Xr ; XR Xr ; XR Y ; XR Y  Phenotype: 2 Red eyed females and 2 Red eyed males  (6) 2.5.3 Males have one allele (not chromosome), so only one recessive allele will show the phenotype,  but females need two recessive alleles to show in the phenotype.  (Any 2 x 1) (2) [40] Copyright reserved Please turn over

Downloaded from hlayiso.com (EC/SEPTEMBER 2015) LIFE SCIENCES P2 5 QUESTION 3 3.1 3.1.1 P1 Phenotype Black short fur x White long fur  Genotype BbSs x bbss Meiosis   Gametes BS ; Bs ; bS ; bs x bs ; bs ; bs ; bs  (OR only one bs) Fertilisation F1 Gametes BS Bs bS bs bs BbSs Bbss bbSs bbss  bs BbSs Bbss bbSs bbss bs BbSs Bbss bbSs bbss bs BbSs Bbss bbSs bbss (6) 3.1.2 Phenotype: 1 black short fur ; 1 black long fur  1 white short fur ; 1 white long fur  (2) 3.2 3.2.1 Most people  have a poor knowledge about GM foods.  Only a very small percentage believed that they are knowledgeable about GM foods.  (3) 3.2.2 People in the rural areas would have been even less knowledgeable  about GM foods because they are less educated and have less access to knowledge.  (2) OR People in rural areas are often farmers  so they will be more knowledgeable about GM foods.  3.2.3 Plants that have had their genes manipulated  to make it better in some  way. (2) 3.2.4 (a)  It will allow for the production of medication or other resources more cheaply.   Pest resistant and drought resistant plants can be produced.   Crop yield can be increased  thereby increasing food security.  The shelf life of fruit and vegetable can be increased  thus decreasing wastage. (Any 2 x 1) (2) (b)  Initially it is an expensive process.  The money could be used for other needs.  We are interfering with nature as we are trying to play God.   It may have potential health impacts.   We are unsure of long term effects of using GMOs.  (Any 2 x 1) (2) Copyright reserved Pleaseturn Please turnover over

Downloaded from hlayiso.com 6 LIFE SCIENCES P2 (EC/SEPTEMBER 2015) 3.3 3.3.1 Skull B  (1) 3.3.2  Sloping forehead   Pronounced brow ridge   No chin   Protruding jaw / prognathous  Large cranium   Sloping face   Small cranium  (Any 5 x 1) (5) 3.4  Free hands for carrying tools, food, and weapons.   Reduced exposure of their bodies to the hot sun. / Faster cooling of body.  Able to see further distances,  for example over long grass.  Easier to gather food from bushes or low branches.   Upright posture is easier for hunting or fighting.   Increased height to intimidate predators.   Easier carrying of offspring.   A more efficient way of moving than swinging through the trees.   Display of male sex organs for courtship behaviour.  (Any 3 x 1) (3) 3.5.1 Average brain volume of different hominids 1600 1450 1400 1200 1100 Average brain 1000 800 575 volume (cm3) 600 440 450 400 200 0 Hominids Guideline for the assessing of the graph Correct type of graph 1 Title of graph 1 Correct label and scale X-axes 1 Correct label and scale Y-axes 1 Plotting of points 1 mark: 1 to 3 points plotted correctly 2 marks: all 5 points plotted correctly Copyright reserved Please turn over

Downloaded from hlayiso.com (EC/SEPTEMBER 2015) LIFE SCIENCES P2 7 NOTE: If the wrong type of graph is drawn, 1 mark will be lost for:  ‘Correct’ type of graph. If labels of the axes are transposed then 2 marks will be lost for:  ‘Correct’ label and scale for X-axis and Y-axis 3.5.2 Homo sapiens  (1) 3.5.3 The earlier hominids had a smaller brain volume.  As the hominids evolved,  their brain volume increased.  (3) 3.5.4  Process large amount of information   Development of speech / communication  Higher intelligence   Quickly process information   Complex behaviour  (Any 2 x 1) (2) [40] TOTAL SECTION B: 80 Copyright reserved Pleaseturn Please turnover over

Downloaded from hlayiso.com 8 LIFE SCIENCES P2 (EC/SEPTEMBER 2015) SECTION C QUESTION 4 4.1 Mutation - Mutation is any change in the genetic composition of an organism, - resulting in a change in the structure /sequence of the genes. - It influences the process of protein synthesis,  resulting in a different protein  or no protein being formed. - This will then lead to different characteristics  in the organisms resulting in a change in the phenotype. Max. 6 Effects of mutation - The effects can be harmful /lethal, harmless /neutral and useful/beneficial.  - It is the useful mutations and sometimes the harmful mutations that contribute to genetic variation  and - if mutation occurs in a somatic cell,  no genetic variation occurs  because these are not inherited. - If the mutation occurs in a gamete  or in cells that give rise to gametes, it will be transmitted to the offspring, i.e. it must be an inheritable variation for a particular trait  Max. 4 Natural selection - Mutations form evolution. - Organisms produce a large number of offspring,  with a great deal of variation amongst the offspring.  - Some of these will have favourable characteristics / advantages to survive a changing environment.  - This will enable them to survive  - Then they pass on their favourable characteristics to their offspring, which will then result in the formation of a new species /speciation occurs. - Those with the unfavourable  characteristics will not adapt  to the environment and die out /extinct. Max. 7 (17) Copyright reserved Please turn over

Downloaded from hlayiso.com (EC/SEPTEMBER 2015) LIFE SCIENCES P2 9 Marking guidelines for the essay Criterion Relevance (R) Logical Comprehensive sequence (L) (C) In this Only information relevant Logical flow in Mutation, its effect essay to mutation, its effects answer with and influence on and influence on regards to how variation and variation and natural mutation leads natural selection selection are given. to variation, are explained with and natural a clear selection understanding. explained. Mark 1 1 1 Synthesis (3) TOTAL SECTION C: 20 GRAND TOTAL: 150 Copyright reserved Pleaseturn Please turnover over