Life Sciences Grade 12 Eastern Cape June 2024 Memo (English)

NATIONAL SENIOR CERTIFICATE GRADE 12 JUNE 2024 LIFE SCIENCES MARKING GUIDELINE MARKS: 150 This marking guideline consists of 9 pages.

2 LIFE SCIENCES (EC/JUNE 2024) PRINCIPLES RELATED TO MARKING LIFE SCIENCES 1. If more information than marks allocated is given Stop marking when maximum marks are 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 provincial marking guideline 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/JUNE 2024) LIFE SCIENCES 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 (EC/JUNE 2024) SECTION A QUESTION 1 1.1 1.1.1 C ✓✓ 1.1.2 A ✓✓ 1.1.3 D ✓✓ 1.1.4 A ✓✓ 1.1.5 D ✓✓ 1.1.6 D ✓✓ 1.1.7 C ✓✓ 1.1.8 D ✓✓ 1.1.9 B ✓✓ 1.1.10 C ✓✓ (20 x 1) (20) 1.2 1.2.1 Haemophilia ✓ 1.2.2 Anaphase 1 ✓ 1.2.3 Non-disjunction ✓ 1.2.4 Chromosome ✓ 1.2.5 Centriole ✓/centrosome 1.2.6 Multiple sclerosis ✓ 1.2.7 Short-sightedness ✓/Myopia 1.2.8 Auditory nerve ✓ 1.2.9 Oestrogen ✓ 1.2.10 Amniotic ✓ fluid (10 x 1) (10) 1.3 1.3.1 A only ✓✓ 1.3.2 B only ✓✓ 1.3.3 B only ✓✓ (6) 1.4.1 (a) E✓ (1) (b) A✓ (1) (c) C✓ (1) 1.4 1.4.2 F ✓ motor neuron ✓/efferent neuron (2) 1.4.3 D to E ✓ (1) 1.5 1.5.1 (a) A ✓ ciliary muscle ✓ (2) (b) C ✓ iris ✓ (2) (c) D ✓ cornea ✓ (2) 1.5.2 Accommodation ✓ (1) 1.5.3 (Diagram) 2 ✓ (1) TOTAL SECTION A: 50 Copyright reserved Please turn over

(EC/JUNE 2024) LIFE SCIENCES 5 QUESTION 2 2.1 2.1.1 (James) Watson ✓ (1) 2.1.2 double helix ✓ (1) 2.1.3 Sample 1 ✓ (1) 2.1.4 • In Sample 1 the number of A/adenine equals the number of T/thymine and G/guanine is equal to C/cytosine ✓✓/In a DNA molecule A/G and T/C are complementary pairs and are therefore equal. OR • There is no U/uracil in sample 1 ✓✓/DNA does not contain U/uracil. (2) 2.1.5 Phosphate (Deoxyribose) Sugar Nitrogenous base Marking guideline for drawing a nucleotide: Criteria Mark allocation Phosphate diagram and labelled in correct position 1 mark Sugar diagram and labelled in correct position 1 mark Nitrogenous base diagram and labelled in correct position 1 mark (3) 2.1.6 DNA RNA Has thymine base ✓ Has uracil base ✓ Deoxyribose sugar ✓ Ribose sugar ✓ Table ✓ + any ONE difference ✓✓ (3) 2.2.1 A-U-G-A-G-C-G-U-A ✓✓ (2) 2.2.2 • The (double helix) DNA unwinds ✓ • The (double-stranded) DNA unzips ✓/weak hydrogen bonds break to form two separate strands. • One strand is used as a template ✓ • to form mRNA ✓ • using free floating RNA nucleotides ✓ in the nucleus • which joins to their complimentary bases ✓ / A-U and C-G (Any 4 x 1) (4) 2.2.3 C was replaced with G in DNA … • Therefore, the mRNA will change from G to C ✓ • The tRNA will change from C to G ✓ • This would code for a different amino acid ✓ • Which would code for the protein which breaks down DDT ✓ (4) Copyright reserved Please turn over

6 LIFE SCIENCES (EC/JUNE 2024) 2.3 2.3.1 FSH ✓ / oestrogen (1) 2.3.2 • FSH – follicle starts to develop ✓/grow OR • Oestrogen – endometrium starts to thicken ✓ (NB: Reason for hormone must correspond to hormone given in 2.3.1) (1) 2.3.3 • The corpus luteum does not degenerate ✓ after day 28 • and continues to produce progesterone ✓ • which maintains the endometrium after day 28 ✓/ endometrium does not degenerate (3) 2.3.4 • The zygote ✓ • divides by mitosis ✓ • to form a (solid) ball of cells ✓ • called a morula ✓ • which then develops into a hollow ball of cells ✓ • called the blastula ✓ / blastocyst (6) 2.3.5 • LH ✓ would be monitored. • Ovulation takes place when LH peaks ✓ /reaches maximum. • therefore, the ovum would be available for fertilisation ✓ (3) 2.4 2.4.1 Genetic engineering ✓/ Recombinant DNA (1) 2.4.2 • There will be no nuts as food for humans ✓/ no timber • Which will reduce the number of people ✓ OR • No habitat for wildlife ✓/ Fruit as food for wildlife • Which would reduce the number of animals ✓ (2) 2.4.3 • A plasmid is removed from the bacteria ✓ • it is spliced open ✓ using an enzyme • the desired gene is extracted ✓ • and inserted into the plasmid ✓ • the plasmid is placed back into the bacteria ✓ (5) 2.4.4 • They can become invasive ✓ because they are no longer. • controlled by the disease ✓ (2) 2.4 2.5.1 Metaphase 1 ✓ (1) 2.5.2 • Spindle fibre shorten ✓ • Centromere splits separating each chromosome into two ✓ • daughter chromosomes are pulled to opposite poles ✓ (3) 2.5.3 ovaries ✓ (1) [50] Copyright reserved Please turn over

(EC/JUNE 2024) LIFE SCIENCES 7 QUESTION 3 3.1 3.1.1 Pedigree diagram ✓ (1) 3.1.2 Mutation/gene for disease found on the X/sex chromosomes/ gonosomes ✓ (1) 3.1.3 4✓ (1) 3.1.4 recessive ✓ (1) 3.1.5 • Individuals 2 / 7 / 10 do not have Menkes syndrome ✓ • however, they (2 / 7 / 10) carry the allele ✓ • because they have a child 5 /13 / 15 who has Menkes syndrome ✓ (3) 3.1.6 (a) XR Xr ✓ (1) (b) Xr Y ✓ (1) 3.1.7 P1 Phenotype Male with Menkes Normal Female  x Syndrome Genotype Xr Y x XRXR  Meiosis G/gametes Xr , Y x XR , XR  Fertilisation F1 Genotype XRXr : XRXr : XRY : XRY  Phenotype 2 Normal females: 2 Normal males  *0% chance for the next child to have Menkes syndrome  P1 and F1  Meiosis and fertilisation  *1 compulsory + Any 5 OR P1 Phenotype Male with Menkes Normal Female  x Syndrome Genotype Xr Y x XRXR  G/gametes Xr Y Meiosis XR XR Xr XR Y XR XR Xr XR Y Fertilisation 1 mark for correct gametes  1 mark for correct genotypes  Phenotype 2 Normal females: 2 Normal males  *0% chance for the next child to have Menkes syndrome  P1 and F1  Meiosis and fertilisation  *1 compulsory + Any 5 (6) Copyright reserved Please turn over

8 LIFE SCIENCES (EC/JUNE 2024) 3.1.8 • Males only have 1 X chromosome ✓ / XY • If they carry the Menkes syndrome allele on the X chromosome they will have the disease ✓ (2) 3.2 3.2.1 (a) Eustachian tube ✓ (1) (b) Round window ✓ (1) 3.2.2 (a) G ✓ – auditory canal ✓ (2) (b) B ✓ ‒ semi-circular canals ✓ (2) 3.2.3 (a) • The fluid in the middle ear prevents the ossicles vibrating freely ✓* • Therefore less/no vibrations are transmitted to the oval window ✓ • Less/no pressure wave are set up in the inner ear ✓ • The organ or corti is stimulated less ✓/not stimulated. • Impulse is not sent on the auditory nerve to the cerebrum to be interpreted ✓ (*1 Compulsory + Any 3) (4) (b) Tympanic membrane ✓/ear drum (1) 3.3 3.3.1 (a) cerebellum ✓ (1) (b) Medulla oblongata ✓ (1) 3.3.2 Connects/allows communication between the left and right hemisphere of the cerebrum ✓✓ (2) 3.3.3 A ✓ – cerebrum ✓ (2) 3.3.4 • The cerebellum is damaged ✓ • Due to no coordination of the voluntary movements ✓ by the cerebellum • The cerebellum is responsible or balance and coordination ✓ (3) 3.4 3.4.1 to gain muscle strength, shape and performance ✓ (1) 3.4.2 (a) Male fertility ✓ (1) (b) AAS ✓ (not effect of AAS) (1) 3.4.3 same age ✓ of males same amount of AAS ✓ taken (2) 3.4.4 • Acts as a control ✓ • To show the results obtained by Group B ✓ • Are caused by the AAS ✓ • And not by the exercise ✓ (Any 3 x 1) (3) Copyright reserved Please turn over

(EC/JUNE 2024) LIFE SCIENCES 9 3.4.5 The higher the level of testosterone ✓ the higher the sperm count ✓ Testosterone stimulates the production of sperm ✓ (3) 3.4.6 High temperatures ✓ would cause sperm to not mature ✓/be deformed (2) [50] TOTAL SECTION B: 100 GRAND TOTAL: 150 Copyright reserved Please turn over