Life Sciences Grade 12 Paper 2 Northern Cape Mock 2025 Memo

DEPARTMENT OF EDUCATION DEPARTEMENT VAN ONDERWYS LEFAPHA LA THUTO ISEBE LEZEMFUNDO [ GRADE 12 | LIFE SCIENCES PAPER 2 SEPTEMBER 2025 MARKING GUIDELINES MARKS: 150 These marking guidelines consist of 14 pages. Copyright reserved Please turn over

NC/September 2025 PRINCIPLES RELATED TO MARKING LIFE SCIENCES 1. 10. 11. 12. 13. 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. If, for example, three reasons are required and five are given Mark the first three irrespective of whether all or some are correct/incorrect. If whole process is given when only a part of it is required Read all and credit the relevant part. If comparisons are asked for, but descriptions are given Accept if the differences/similarities are clear. If tabulation is required, but paragraphs are given Candidates will lose marks for not tabulating. If diagrams are given with annotations when descriptions are required Candidates will lose marks. If flow charts are given instead of descriptions Candidates will lose marks. 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 become correct again, resume credit. Non-recognised abbreviations Accept if first defined in answer. If not defined, do not credit the unrecognised abbreviation, but credit the rest of the answer if correct. Wrong numbering If answer fits into the correct sequence of questions, but the wrong number is given, it is acceptable. If language used changes the intended meaning Do not accept. Spelling errors If recognisable, accept the answer, provided it does not mean something else in Life Sciences or if it is out of context. If common names are given in terminology Accept, provided it was accepted at the provincial memo discussion meeting. Copyright reserved Please turn over

14. 15. 16. 1s. 18. 19. 20. NC/September 2025 if only the letter is asked for, but only the name is given (and vice versa) Do not credit. If units are not given in measurements Candidates will lose marks. Memorandum will allocate marks for units separately. Be sensitive to the sense of an answer, which may be stated in a different way. Caption All illustrations (diagrams, graphs, tables, etc.) must have a caption. Code-switching of official languages (terms and concepts) A single word or two that appear(s) in any official language other than the learner's 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. Changes to the memorandum No changes must be made to the memorandum without the approval of the examiner and moderator. Official memoranda Only memoranda bearing the signatures of the provincial internal moderator and distributed by the Provincial Education Department via the districts must be used. Copyright reserved Please turn over

NC/September 2025 SECTION A QUESTION 1 1.1 Bvv Avy Dvv Dvv Avy Cvv Crs AVY CVv 0 Byv (10x 2) (20) Mets Eats Ee: Dadie Eats da BoeVourono 1.2 Cytokinesis ¥ Genome ¥ Haemophilia ~ Homologous structures ¥ Continuous V variation Homologous chromosomes ¥ Theory ¥ Phenotype ¥ Spindle fibres V/spindle threads/spindle fibrils 0 Allele Y (not multiple alleles) (10x1) (10) oe aes Sees oe ey eres NNNNNNNNNN 2OMNOONRWNH> 1.3 qari Aonly ¥¥ 1232 Both A and B Vv 1:33 None Vv¥ (3x2) (6) 1.4 1.4.1 (a) B— Adenine ¥ (1) (b) C — deoxyribose v sugar (1) (c) D— phosphate v molecule (1) 1.4.2 (weak) hydrogen “/H bond (1) 1.4.3 Interphase V (1) (5) Copyright reserved Please turn over

NC/September 2025 1.5 1.5.1 - Identify bodies v/victims of disasters/crime - Identify inherited disorders ~/organ donor - Identify criminal suspect “/forensic evidence pointing to possible suspect/exonerate falsely accused individuals - Identify different pathogens v/strands of viruses and bacteria - Identify animal/plants species v/manage conservation - Trace family history ~/discover family relationships /genealogy Trace wildlife populations v (Mark first TWO only) (2) 1.5.2 Genes V/alleles (1) 15S Mia ¥ (1) (4) 16 1.6.1 Gene Y mutation (1) 16:2 46 v chromosomes/23 (chromosome) pairs (1) 1.6.3 Males ¥ (1) 1.6.4 XKXkK vv (2) (5) TOTAL SECTION A: 50 Copyright reserved Please turn over

SECTION B QUESTION 2 ZF 2.1.1 2.1.2 2.1.3 2.1.4 2.2 2.2.1 Copyright reserved NC/September 2025 (a) A-—nucleus ¥ (1) (b) B-—mRNA “/messenger RNA (1) (c) C-—ribosome ¥ (1) (d) 1 -transcription “ (1) - Carries hereditary characteristics Vv - Controls the function of cells ¥ - Controls the synthesis (making/producing) of proteins ~/ acts as a template for formation of MRNA (Mark first ONE only) Any 1 (1) (James) Watson, (Francis) Crick and (Maurice) Wilkens v ¥ (2) - Translation v* - Each tRNA carries a specific amino acid. v - When the anticodon on the tRNA v - matches the codon on the MRNA v - Then tRNA brings the required amino acid to the ribosome. ¥ - Amino acids become attached to each other by peptide bonds v - to form the required protein. v *1 compulsory mark + Any 5 (6) (13) - Production of haploid gametes v/cells - The halving effect of meiosis overcomes the doubling effect of fertilisation ~/maintaining a constant chromosome number Contributes to/ensures genetic variation Vv (Mark first THREE only) (3) Please turn over

NC/September 2025 2.2.2 The DNA content during the different phases of the nuclear cycle. 250 4 N oO oO 1 150 + DNA content (%) 3 3S & & ge PY = aS) & CS ? e eS e x? 0 OS Oy NS x RY g Fe) x roy Ro & xe gt * v Phase of nuclear cycle Guideline for assessing the graph: SKILL SYMBOL MARK Type of graph: histogram T 1 Caption for graph: includes both variables o The relative amounts of DNA during mitosis and meiosis c 1 o The DNA content during the different phases of the nuclear cycle Scale for Y-axis and width of bars on X-axis s 1 Label for X-axis: Label and names of phases (accept if given in a key) L 1 Label for Y-axis: Label and unit 1: 1-5 correct bars Grewia ot Bars a 2: All bars correct NOTE: If the wrong type of graph is drawn: | - Marks willbe lost fortype _(T) If axes are transposed: -Marks will be lost for labeling (L) -Marks will be lost for scale (S) (6) 2.2.3 (a) - DNA replication will take place v - and the DNA content will double v/100 to 200 (not increase) (2) (b) - The number of chromosomes will be halved ~/ 100 to 50 chromosome pairs split (divide) - during anaphase I v /anaphase of meiosis I (2) (13) Copyright reserved Please turn over

NC/September 2025 23 2314 (a) rv (1) (b) Rrv (1) 2.3.2 50%% (1) 2.3.3 Complete VY dominance (1) 2.3.4 : Grandmother Grandfather Father Mother [ Daughter 1 Daughter 2 Son KEY: Non-roller male O Non-roller female Bw Roller male al Roller female Guideline for assessing the pedigree diagram: SKILL SYMBOL | MARK Generation 1: G 1 Correct shapes and shading of connected grandparents Generation 2: P 1 Correct shapes and shading of connected parents Generation 3: Cc 1 Correct shapes and shading of connected children Names of all individuals supplied OR No names given: Key included N 1 OR Correct caption (4) (8) Copyright reserved Please turn over

NC/September 2025 24 241 - An organism possesses two alleles ~/'factors' which separate (segregate) so that - each gamete contains only one of these alleles v/’factors’ (2) 24 242 Autosomes ¥ (1) 2.4.3 Male ¥ (1) 2.44 - The gonosomes Y/chromosome pair number 23 - are not identical v/XY OR - There is a Y V/smaller chromosome - at 23v position/pair (2) 2.4.5 - During Anaphase v‘(1 or 2) - the chromosomes pair number 23 “~/gonosomes - of the (female/male) parent does not separate ~/there is non- disjunction in the person/parent - Agamete with XX “/XY-chromosome formed v. - During fertilisation the abnormal gamete/sperm/ovum fused with a normal gamete/sperm/ovum ¥ - to form the zygote with XXY v/47 chromosomes Any4 (4) (10) Copyright reserved Please turn over

NC/September 2025 2.5 Pi phenotype (Blood group) AB X (blood group) A ¥ Do not refer to heterozygous/homozygous genotype AB xX Ow Meiosis Gametes/G A iB a i x Fertilisation = all Fi genotype JAJA 13) rye OAT Y F1 phenotype (2/50%) blood group A (1/25%) blood groupB_ fw” (1/25%) blood group AB P1 and Fiv Meiosis and fertilisation Vv OR Pi phenotype (Blood group) AB X (blood group) A v Do not refer to heterozygous/homozygous genotype Ala X lAi ¥ Meiosis Gametes 1A 18 \A AIA AB a i Vi 18j Fertilisation 1 mark for correct gametes 1 mark for correct genotypes F1 phenotype (2/50%) blood group A (1/25%) blood group B_ |v (1/25%) blood group AB P; and Fi ¥ Meiosis and fertilisation ¥ Copyright reserved Any 6 Any6 (6) [50] Please turn over

NC/September 2025 QUESTION 3 3.1 - The insulin producing gene is cut/isolated from the DNA of a human/ healthy pancreas Y and is inserted into the gene of bacterial DNA “/DNA of E. coli/plasmid this is recombinant DNA v/this bacterium is genetically modified and causes the bacterium/E. coli/culture to produce insulin ~ 3.2 3.241 Homo sapiens ¥ 3.2.2 (Skull) B ¥ 3.2/3 - Allows total awareness V of the environment/sees further over Copyright reserved high grass to sense danger W/look for food - Enables hands to be free ¥ to use implements “/carry objects/protect offspring - Exposes a large surface area ¥ for thermoregulation Y/losing body heat to surroundings in hot conditions/reduces overheating/uses less water - Small surface area exposed to the sun, ¥ reducing overheating V/use less water - Displays (male/female) sex organs ¥ as part of courtship behaviour ¥ (Mark first THREE only) Any 3 x2 (4) (1) (1) (6) Please turn over

3.2.4 NC/September 2025 (Organism) A/Gorilla (Organism) B/Homo Sapiens/ Humans Cranial ridge Y present No cranial ridge V present Smaller) cranium “ Large(r) cranium ¥ (Not *brain/skull') Browridge well developed ” Browridge less developed ¥ (Not ‘no browridge’) Large/well developed canines “ fangs Small/underdeveloped canines “ ino fangs Jaws are prognathous “/Longer jaws/More protruding jaws Jaws are non-prognathous v/ Shorter jaws/Less protruding jaws (Not ‘less prognathous') More pronounced zygomatic arches ¥ Less pronounced zygomatic arches ¥ Foramen magnum is more backward ¥ Foramen magnum is more forward ¥ Sloping face “/forehead Flat face V /forehead (Mark first THREE only) 1v Table+Any3x2 _ (7) (15) 3.3 3.3.1 - The change in characteristics of a species ¥ - over time ¥ (2) 3:312 - Squirrels with sparse hair V resulted in lower(cooler) body temperatures V - Good digging claws v enabled them to dig (make tunnels) in the deep/cool sand.“ (4) Copyright reserved Please turn over

3.4 Copyright reserved NC/September 2025 3.3.3 - The original/ancestral population of the (ground) squirrels ¥ - became separated by the canyon V*/Grand Canyon/deep eroded Colorado River - the population split into two “/divided into a north and south population - the squirrels stopped crossing the canyon because there was no shelter “/shade/temperature too high/desert habitat - there is no gene flow between the north and south population v/between the two squirrel populations - In the south side it was warmer, with less shade v/the squirrels were exposed to heat - inthe north side it was cooler with more shade v/the squirrels were less exposed to heat/the exposure to heat differed in the north and south side - natural selection occurs independently in each of the two populations ¥ - such that the individuals of the two populations become different V from each other - genotypically and phenotypically ~ - even if the two populations were to mix again ¥ - they will not be able to interbreed ¥ - the two populations are the Abert and Kaibab squirrels “/are different species *1 compulsory mark + Any 7 3.3.4 - Breeding at different times of the year ¥ - Species-specific courtship behavior ~ - Plant adaptation to different pollinators Vv Infertile offspring ¥ (Mark first TWO only) Any 2 There is a great deal of variation amongst the offspring ¥ Some had favourable characteristics and some did not ¥ There is a change in the environmental conditions W Whilst organisms with unfavourable characteristics, which made them less suited, died W Whilst organisms with favourable characteristics made them more suited, survived Y and Reproduce(d) “ the allele for favourable characteristic is passed on to their offspring W The next generation will therefore have a higher proportion of individuals with the favourable characteristics Vv Any 7 (8) (2) (7) Please turn over

NC/September 2025 3.5 3.51 (a) (Exposure to) DDT ~/insecticide (1) (b) Resistance of mosquitoes ¥ (1) 3.6.2 (a)- Decide on the duration v of the investigation - Decide on the area V to capture mosquitoes - Decide on the sample size ¥ - Decide on date “/time of capturing mosquitoes - Decide on the concentration of DDT v used - Decide how long the mosquitoes must be exposed to DDT v¥ - Decide how to record the results Y/on the form to record the results - Decide on type of mosquitoes V/species of mosquitoes - Ask permission Y (from authorities/land-owner) to conduct the investigation - Select apparatus vY to capture mosquitoes Train research assistants V (Mark first TWO only) Any2 = (2) (b) - Same time (1 hour per day) “ for the duration of the investigation - Same laboratory conditions Y for the full period of the investigation - Same dose (4%) of DDT VY for the full period of the investigation - All mosquitos must be healthy for the full period of the investigation (Mark first TWO only) Any2 = (2) (c)- Mosquitoes developed a resistance to DDT Vv/ resistance to DDT will increase over time OR - DDTis annotan effective insecticide to control the spread of mosiquitoes VV (2) (8) [50] TOTAL SECTION B: 100 GRAND TOTAL: 150 Copyright reserved