Life Sciences Grade 12 P2 Eastern Cape Mock 2018 Memo (Eng)

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE GRADE 12 SEPTEMBER 2018 LIFE SCIENCES P2 MARKING GUIDELINE MARKS: 150 This marking guideline consists of 10 pages.

Downloaded from hlayiso.com 2 LIFE SCIENCES P2 (EC/SEPTEMBER 2018) 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

Downloaded from hlayiso.com 3 LIFE SCIENCES P2 (EC/SEPTEMBER 2018) 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

Downloaded from hlayiso.com 4 LIFE SCIENCES P2 (EC/SEPTEMBER 2018) SECTION A QUESTION 1 1.1 1.1.1 B  1.1.2 D  1.1.3 B  1.1.4 D  1.1.5 C  1.1.6 C  1.1.7 D  1.1.8 C  1.1.9 B  1.1.10 A  (10 x 2) (20) 1.2 1.2.1 Variation  1.2.2 Autosomes  1.2.3 Fossils  1.2.4 Alleles  1.2.5 Haemophilia  1.2.6 Biotechnology  1.2.7 Phylogenetic tree  1.2.8 Foramen magnum  1.2.9 Mitochondrial DNA  (9 x 1) (9) 1.3 1.3.1 Both A and B  1.3.2 A only  1.3.3 B only  (3 x 2) (6) 1.4 1.4.1 550 mya (Accept any value between 545 and 555) (1) 1.4.2 Bacteria  (1) 1.4.3 Ferns  (1) 1.4.4 Birds  (1) 1.4.5 Reptiles  (1) 1.4.6 They share a more recent common ancestor  (1) Copyright reserved Please turn over

Downloaded from hlayiso.com 5 LIFE SCIENCES P2 (EC/SEPTEMBER 2018) 1.5 1.5.1 Cloning  (1) 1.5.2 Ovum  (1) 1.5.3 Uterus  (1) 1.5.4 46  (1) 1.5.5 - Production of children for infertile couples  - Compensating for the loss of a loved one  - Cloning of organs from a person’s tissue and used as a transplant  - Young cells cloned to prolong life / Delayed aging (Any 1) (Mark first ONE only) (1) 1.6 - Breeding at different times of the year  - Species-specific courtship behaviour  - Adaptation to different pollinators  - Infertile offspring  - Prevention of fertilisation  (Mark first FOUR only (Any 4) (4) TOTAL SECTION A: 50 Copyright reserved Please turn over

Downloaded from hlayiso.com 6 LIFE SCIENCES P2 (EC/SEPTEMBER 2018) QUESTION 2 2.1 2.1.1 UAC  (1) 2.1.2 (a) Methionine – Arginine – Glycine  (2) (b) - The corresponding mRNA codon will be AUC  - resulting in isoleucine being picked up by tRNA  - resulting in a different protein  (3) 2.2 2.2.1 (a) Black fur (1) (b) White fur (1) 2.2.2 1BB :2Bb :1 bb  (2) 2.2.3 12  (1) 2.2.4 P1 Phenotype Black X White  Genotype Bb X Bb  Meiosis G/gametes B, b X IB , i Fertilisation F1 Genotype Bb Bb; bb bb * Phenotype Black white* P1 and F1  Meiosis and fertilisation  OR P1 Phenotype Black X White  Genotype Bb X bb  Meiosis Gametes B b Fertilisation b Bb bb b Bb bb 1 mark for correct gametes 1 mark for correct genotypes * F1 Phenotype Black , white * P1 and F1  Meiosis and fertilisation  *(compulsory 2 + any 4) (6) Copyright reserved Please turn over

Downloaded from hlayiso.com 7 LIFE SCIENCES P2 (EC/SEPTEMBER 2018) 2.3.1 X – Centromere  Y – Homologous chromosomes  (2) 2.3.2 Metaphase I  (1) 2.3.3 - Homologous chromosomes / chromosome pairs - are randomly arranged  - at the equator of the cell - attached to spindle fibres  (Any 3) (3) 2.3.4 - Random arrangement of chromosomes introduces genetic variation in gametes which - may lead to organisms which are better suited  to a changing environment OR - It results in chromosomes moving apart - resulting in halving of chromosome number/haploid gametes OR - Contraction of spindle fibres  - allows chromosomes to separate  move to the poles (2) - 2.4 2.4.1 - The original population of pistol shrimp  - was separated into different populations - by a narrow strip of land* /Panama - There was no gene flow  between the populations - Each population was exposed to different environmental conditions /selection pressures - Natural selection occurred independently  in each population - The individuals of the two shrimp populations became different  from each other - genotypically and phenotypically  - Even if the two populations were to mix again  - they would not be able to interbreed  Any 6 +*1 (7) 2.4.2 - Speciation resulted in two species  / new species - thereby increasing the biodiversity  of the pistol shrimp. (2) 2.5 2.5.1 IA and IB  (2) 2.5.2 Baby Y  and Z  (2) 2.5.3 IAi  (2) [40] Copyright reserved Please turn over

Downloaded from hlayiso.com 8 LIFE SCIENCES P2 (EC/SEPTEMBER 2018) QUESTION 3 3.1 3.1.1 Pedigree  diagram (1) 3.1.2 Recessive  (1) 3.1.3 - Neither individual 1 and 2 have the disease  but (2) - they have two children 7 and 8 with the disease.  OR - Individual 3 and 4 do not have the disease  - but have child 12 with the disease.  3.1.4 (a) Nn  (1) (b) nn  (1) 3.1.5 - Individual 11 can only have genotype NN  - If crossed with individual 10 with the genotype nn  - there is no chance/ 0% probability of having a child with the disease  - as all offspring will have the genotype Nn  (Any 3) (3) 3.2 3.2.1 (a) Fruit colour  and Bird species  (2) (b) Preference of fruit colour  (1) 3.2.2 - Same number of birds captured  - Petri dish was identical - Same number of fruits in each petri dish  / 2 red and 2 orange fruits - Cages of equal size  - Only the first choice was recorded  (Any 2) (2) (Mark first TWO only) 3.2.3 - The sample size of the bird species was increased  when 10 birds were used instead of one. - improving the reliability of the investigation (2) 3.2.4 30 ✓x 100✓ = 75✓% 40 (3) Copyright reserved Please turn over

Downloaded from hlayiso.com 9 LIFE SCIENCES P2 (EC/SEPTEMBER 2018) 3.2.5 - There is variation in fruit colour ✓ in the salmonberry plants - Some are red and some are orange ✓ - Birds prefer the red fruits and disperse their seeds ✓/ red fruit are selected and their seeds are dispersed by birds ✓ - Orange fruits are not preferred, and their seeds are not dispersed ✓/ orange fruits are not selected and their seeds are not dispersed by birds - The number of orange fruit will decrease ✓ - due to there being no germination of their seeds ✓ - The seeds of red fruits germinate ✓ - more red fruits are produced ✓ - the allele for producing red fruits is passed on to offspring ✓leading to an increase in the proportion of salmonberry plants that produce red fruits over many generations (Any 6) (6) 3.3 3.3.1 (a) (Homo) erectus  (1) (b) (Homo) habilis  (1) 3.3.2 4  million years ago (1) 3.3.3 Fossil  evidence (Mark first ONE only) (1) 3.3.4 (a) Raymond Dart  (1) (b) Taung village  / Sterkfontein (1) 3.3.5 - Australopithecus has well developed brow ridges  whereas in - Homo sapiens sapiens brow ridges are not well developed.  - The jaw is more prognathous  (protruding) in Australopithecus and - less prognathous  (protruding) in Homo sapiens sapiens (4) 3.3.6 Cranial capacity increased  (1) 3.4 According to punctuated equilibrium: - Evolution involves long periods of time  - where species do not change  /change very little - This alternates with short periods of time  - where rapid changes occur  through natural selection (4) [40] TOTAL SECTION B: 80 Copyright reserved Please turn over

Downloaded from hlayiso.com 10 LIFE SCIENCES P2 (EC/SEPTEMBER 2018) SECTION C QUESTION 4 DNA Replication - is the process by which DNA makes an identical copy of itself  - It occurs during interphase  - just before cell division  (mitosis and meiosis) - It must occur so that DNA is shared amongst daughter cells during cell division  - so that each daughter cell has the same number of chromosomes as the original cell  It takes place as follows: - Double helix DNA unwinds  - and unzips  / separates when - the weak hydrogen bonds break  - and this is controlled by enzymes  - Each original DNA strand is used as a template to form a new strand - by attaching to free nucleotides  from the nucleoplasm - to form complementary strands  (A to T, C to G) - Each DNA molecule now consists one original strand and one new strand  - The result is two genetically identical DNA molecules  - The entire process is controlled by enzymes  (Max. 13) (13) Uses of DNA profiling DNA profiles are used for: - Testing for the presence of specific alleles /genes that cause a genetic disorder - Investigating crimes  - Establishing paternity / whether a person is the father of a child or not - Identifying family relationships  e.g. siblings or cousins - Identifying organisms from their remains  - Establishing matching tissues for organ transplants  (Max. 4) (4) Content: (17) Synthesis: (3) [20] ASSESSING THE PRESENTATION OF THE ESSAY Criterion Relevance (R) Logical sequence (L) Comprehensive (C) Generally All information provided Ideas are arranged in a All aspects of the is relevant to the logical sequence. essay have been question. sufficiently addressed. In this Only information relevant The description of DNA At least the essay in Q4 to the description of DNA replication and uses of following marks replication and the uses DNA profiling is should be obtained: of DNA profiling. presented in a logical - 8/13 for the No irrelevant information and sequential manner. description of included. DNA replication and - 3/4 for the uses of DNA profiling. TOTAL SECTION C: 20 GRAND TOTAL: 150 Copyright reserved Please turn over