Life Sciences Grade 12 P2 Eastern Cape Mock 2023 Memo (Eng)

NATIONAL SENIOR CERTIFICATE GRADE 12 SEPTEMBER 2023 LIFE SCIENCES P2 MARKING GUIDELINE MARKS: 150 This marking guideline consists of 11 pages.

2 LIFE SCIENCES P2 (EC/SEPTEMBER 2023) 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 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 are incorrect, do not credit. If sequence and links become 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 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 recognisable, accept the answer, provided it does not mean something else in Life Sciences or if it is out of context. 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. Copyright reserved Please turn over

(EC/SEPTEMBER 2023) LIFE SCIENCES P2 3 15. If units are not given in measurements Candidates will lose marks. Marking guideline 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 appear(s) 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. Copyright reserved Please turn over

4 LIFE SCIENCES P2 (EC/SEPTEMBER 2023) SECTION A QUESTION 1 1.1 1.1.1 B ✓✓ 1.1.2 C ✓✓ 1.1.3 A ✓✓ 1.1.4 B ✓✓ 1.1.5 D ✓✓ 1.1.6 A ✓✓ 1.1.7 B ✓✓ 1.1.8 D ✓✓ 1.1.9 A ✓✓ 1.1.10 C ✓✓ (10 x 2) (20) 1.2 1.2.1 Chromosomes ✓ 1.2.2 Gene ✓ 1.2.3 (Gregor) Mendel ✓ 1.2.4 Peptide ✓ bond 1.2.5 Nucleotides ✓ 1.2.6 Stem cells ✓ 1.2.7 Prognathous ✓ 1.2.8 Punctuated equilibrium ✓ (8 x 1) (8) 1.3 1.3.1 A only ✓✓ 1.3.2 B only ✓✓ 1.3.3 A only ✓✓ (3 x 2) (6) 1.4.1 Crossing over ✓ (1) 1.4.2 Prophase 1 ✓ (1) 1.4.3 (a) Centromere ✓ (1) (b) Chromatid ✓ (1) (c) Homologous chromosomes ✓ (1) 1.4.4 Mark allocation Single chromatid drawn ✓ Chromatid white/unshaded at top and shaded at bottom ✓ p Correct letters (p q R S T) on chromatid ✓ q C R S T (3) Copyright reserved Please turn over

(EC/SEPTEMBER 2023) LIFE SCIENCES P2 5 1.5 1.5.1 Dihybrid cross ✓ (1) 1.5.2 GB Gb gB gb ✓ (1–3 correct) ✓✓(all 4 correct) (2) 1.5.3 (a) Grey ✓ (1) (b) ggbb ✓✓ (2) (c) Grey hair ✓ Black eyes ✓ (2) (8) TOTAL SECTION A: 50 Copyright reserved Please turn over

6 LIFE SCIENCES P2 (EC/SEPTEMBER 2023) QUESTION 2 2.1 2.1.1 (a) DNA ✓ (1) (b) mRNA ✓ (1) 2.1.2 Transcription ✓ (1) 2.1.3 Nucleus ✓ (1) 2.1.4 ACG✓ GCG✓ UGG✓ (3) 2.1.5 Cysteine ✓ –Valine ✓ – Threonine ✓ (3) 2.1.6 - The mRNA/codon/base is GCG/C instead of GUG/U on molecule 2 ✓ - Therefore, the tRNA/anticodon will be CGC ✓ instead of CAC. - Therefore, the amino acid will be Alanine ✓ instead of Valine - Therefore, a different protein will be coded for. ✓ (4) 2.2 2.2.1 (a) Xn ✓ (1) (b) Xn Xn ✓✓ (2) 2.2.2 - They struggle to see clearly at night ✓ - They experience visual problems like short-sightedness ✓ - Loss of visual sharpness ✓ (Mark first TWO only) (Any 2 x 1) (2) 2.2.3 (a) Normal night vision✓ (1) (b) - A man/boy has only one X chromosome ✓ - The son will get his X chromosome from his mother ✓ - If the mother’s X chromosomes are both for normal night vision ✓ then the boy will not have night blindness. (3) 2.3 2.3.1 - All the black bars of the DNA profile of the child ✓ - that do not match the DNA profile of the mother ✓ - match the DNA profile of dad 2 ✓ (3) 2.3.2 - The baby carries two recessive alleles ✓/ is ii - Dad 1 carries the allele for blood type A/ IA and the allele for blood type B/ IB. ✓ - Therefore, he cannot pass on the allele for blood type O ✓/ i to the child OR - The baby carries two recessive alleles ✓ (one from each parent) - The mother has one recessive allele ✓ - Dad 1 has no recessive allele ✓ - Therefore, he cannot pass on the allele for blood type O/I to the child (3) Copyright reserved Please turn over

(EC/SEPTEMBER 2023) LIFE SCIENCES P2 7 2.3.3 P1 Phenotype Blood type A x Blood type B male/dad female/mother Genotype IA i ✓ x IB i ✓ Meiosis G/gametes IA , i x IB , i ✓ Fertilisation F1 Genotype IA IB ; IA i ; IBi ; ii✓ Phenotype 1 AB : 1 A : 1 B : 1O They have a 25% ✓*chance of having a child with blood group O. OR P1 Phenotype Blood type A x Blood type B male/dad female/mother Genotype IA i ✓ x IB i ✓ Meiosis G/gametes IA , i x IB , i ✓ Fertilisation Gametes IA i F1 IB IA IB IB i i IA i ii Correct genotypes ✓ Phenotype 1 AB : 1 A : 1 B : 1O They have a 25% ✓*chance of having a child with blood group O. P1 and F1✓ Meiosis and fertilisation ✓ Any 5 + *1 Compulsory (6) 2.3.4 - Many people have the same blood groups ✓ - Therefore, blood groups can only tell us who is not the father ✓ (2) 2.3.5 - Determine the probability or causes of genetic defects - Establish the compatibility of tissue types for organ transplants - Identify relatives - Identify crime suspects in forensic investigations (Mark first TWO only) (Any 2 x 1) (2) Copyright reserved Please turn over

8 LIFE SCIENCES P2 (EC/SEPTEMBER 2023) 2.4 2.4.1 Anaphase 1 ✓ (1) 2.4.2 - Homologous chromosomes separate ✓ and move to the poles OR - Whole/double thread chromosomes ✓ move to the poles ✓ (Mark first answer only) (Any 1 x 2) (2) 2.4.3 (a) Forms the spindle fibre ✓ (1) (b) Pulls the chromosomes towards the poles ✓ (1) 2.4.4 Non-disjunction ✓ (1) 2.4.5 - Random arrangement ✓/ maternal and paternal chromosomes arrange randomly on the equator - This leads to a mixture of maternal and paternal information in the gametes that form ✓ - Non-disjunction ✓/homologous chromosomes do not separate/ chromosomal mutation - Therefore, one gamete will have an extra chromosome and the other will have one less ✓ - Crossing over ✓ has occurred - Therefore, chromosomes have a mixture of maternal and paternal genetic information ✓ (Mark first TWO only) (Any 2 x 2) (4) 2.4.6 3✓ (1) [50] Copyright reserved Please turn over

(EC/SEPTEMBER 2023) LIFE SCIENCES P2 9 QUESTION 3 3.1 3.1.1 Artificial Selection ✓/Selective breeding (1) 3.1.2 - Shorter and wider ✓ - Pale brown fur with black stripes ✓ - Stripes only on the front of their body ✓ (Any 2 x 1) (2) 3.1.3 - If they can interbreed ✓ - and produce fertile offspring ✓ (2) 3.1.4 - Extinction of some species opens new ecological niches ✓ - which may lead to the formation of new species ✓ (2) 3.2 3.2.1 Homo naledi ✓ (1) 3.2.2 It belongs to the same genus as modern humans ✓ (Mark first ONE only) (1) 3.2.3 - Australopithecus sediba would be bipedal if: - It had and S-shape spine ✓ - The hips were wider and shorter ✓ - The foramen magnum was in a forward position ✓ (Mark first THREE only) (3) 3.2.4 Australopithecus africanus ✓ (1) 3.2.5 - the site has produced a large number of hominin fossils ✓ - in the human linage ✓ (2) 3.2.6 - mtDNA is passed from mother to child ✓ - By following mutations in mtDNA ✓ - we can trace our female line of descent ✓ - which leads to an ancestral female who lived in East Africa about 150 000 years ago ✓ (4) 3.3 3.3.1 Biological evolution is the change in the characteristics of species over time ✓✓ (2) 3.3.2 Theory of Evolution is regarded as a scientific theory since: - various hypotheses relate to evolution ✓ - they have been tested and verified over time ✓ (2) 3.3.3 HYPOTHESIS THEORY possible prediction/explanation of scientific explanation of events phenomena after observation ✓ supported by results ✓ Based on limited data ✓ It is supported by a lot of evidence ✓ Hypothesis can either be Theories are reliable and the accepted or rejected ✓ basic ideas persist in science ✓ Any 1 x 2 + Table ✓ (Mark first ONE only) (3) Copyright reserved Please turn over

10 LIFE SCIENCES P2 (EC/SEPTEMBER 2023) 3.3.4 - genetics - biogeography - fossils - comparative anatomy (Mark first TWO only) (Any 2 x 1) (2) 3.4 3.4.1 Genetic Engineering ✓/Genetic Modification (1) 3.4.2 Recombinant DNA ✓ (1) 3.4.3 - They will use less insecticide ✓ - And therefore, save money ✓ - OR - They will have a bigger crop yield ✓ - And therefore, earn more money ✓ (Mark first ONE only) (Any 1 x 2) (2) 3.4.4 - The gene could kill other organisms ✓ - that are useful to the environment ✓and therefore, decrease biodiversity (Mark first ONE only) (2) 3.5 3.5.1 treatment ✓ / oral or injectable containing (1) 3.5.2 They used 200 participants ✓ (Mark first ONE only) (1) 3.5.3 100✓ – (28+12+2) ✓ OR 100 ✓ – 42 ✓ = 58 ✓ participants (3) 3.5.4 - They stop going to the clinic ✓* - because they are scared of injection ✓ - because they do not have transport ✓ - because they forget ✓ - because they move away ✓ (Mark first ONE only) ✓* + Any 1 (2) 3.5.5 - Some TB bacteria have resistance to rifampicin/drugs and some do not ✓ - When rifampicin/drugs is given, ✓ - the TB bacteria with resistance to rifampicin survives ✓ - While the TB bacteria with no resistance to rifampicin dies. ✓ - The TB bacteria that survive, reproduce ✓ - and thus, pass on the allele for the resistance to rifampicin to their offspring ✓ - The next generation will therefore have a higher proportion of individuals with rifampicin/drug resistance ✓ (Any 5 x 1) (5) Copyright reserved Please turn over

(EC/SEPTEMBER 2023) LIFE SCIENCES P2 11 3.5.6 - Patients should be - the same age ✓ - same economic level ✓ - same health ✓ / not have other diseases (Mark first TWO only) Any 2 (2) 3.5.7 - To ensure that the tuberculosis bacterium is completely killed ✓ - And the TB does not reoccur ✓ (2) [50] TOTAL SECTION B: 100 GRAND TOTAL: 150 Copyright reserved Please turn over