Life Sciences Grade 12 Paper 2 Limpopo Mock 2022 Memo

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. com GRADE 12 LIFE SCIENCES P2 SEPTEMBER 2022 PREPARATORY EXAMINATION PREPARATORY EXAMINATION MARKS:150 TIME: 2½ HOURS This question paper consists of 17 pages.

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences/P2 2 com Limpopo PED/September 2022 INSTRUCTIONS AND INFORMATION Read the following instructions carefully before answering the questions. 1. Answer ALL the questions. 2. Write ALL the answers in your ANSWER BOOK. 3. Begin the answers to each question at the top of a NEW page. 4. Number the answers correctly according to the numbering system used in this question paper. 5. s.co Present your answers according to the instructions of each question. 6. m ALL drawings should be done in pencil and labelled in blue or black ink. si c 7. Only draw diagrams or flow charts when asked to do so. st 8. an The diagrams in this question paper are NOT all drawn to scale. 9. Do NOT use graph paper. mor 10. ep Non-programmable calculators, protractors and compasses may be used. 11. Write neatly and legibly. hy om fr oa de d do wn l Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences/P2 3 com Limpopo PED/September 2022 SECTION A QUESTION 1 1.1 Various options are provided as possible answers to the following questions. Choose the correct answer and write only the letter (A–D) next to the question number (1.1.1 to 1.1.10) in your ANSWER BOOK, for example 1.1.11 D. 1.1.1 The sequence of nitrogenous bases UCA CGA ACC GCU AAC could represent ... A a gene that codes for one protein. B a DNA strand that codes for one mRNA molecule. C D a chain of five amino acids. s. an mRNA strand that codes for five amino acids.co 1.1.2 A male who is homozygous for blood group A and a m si female with blood group B have children. Which ONE of c the following genotypes is possible in the offspring? st A IA IA an B C IA i ii mor D IB i ep 1.1.3 hy Colour blindness is a sex-linked trait and is caused by a recessive allele on the X chromosome. The pedigree diagram om below shows the inheritance of colour blindness in a family. fr KEY: oa Normal male de Affected male d Normal female do Affected female wn l Persons I and II have a child. What is the chance that the child will be colour-blind? A 0% B 25% C 75% D 100% Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences/P2 4 com Limpopo PED/September 2022 1.1.4 The diagrams below show the forelimbs of some vertebrates The type of evidence for evolution represented is... A fossil evidence B biogeography. C modification by descent D genetic evidence 1.1.5 The diagram below shows a karyotype of a human. Which statement about this karyotype is correct? A Non-disjunction has occurred, and the individual is male. B Non-disjunction has not occurred, and the individual is female. C Non-disjunction has not occurred, and the individual is male. D Non-disjunction has occurred, and the individual is female. Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences/P2 5 com Limpopo PED/September 2022 1.1.6 Changes to the genetic material of organisms can ONLY be inherited by the next generation if they ... A occur in somatic cells. B increase the survival chances of the species. C occur in reproductive cells. D increase the survival chances of an individual. 1.1.7 Below is a list of fossils discovered in South Africa: 1. Taung child 2. Little Foot 3. Karabo 4. Mrs Ples Which of the fossils above are classified in the genus Australopithecus? A 1, 2 and 3 B 1, 2, 3 and 4 C 2, 3 and 4 D 1, 3 and 4 1.1.8 DNA from the cells of an animal was analysed in a laboratory. The results are shown in the table below. Nitrogenous Base Composition X Guanine Y Z 23,4% 26,3% 26,7% 23,6% Which of the following is a possible correct identification of the bases X, Y and Z? X Y Z A cytosine adenine thymine B thymine adenine cytosine C adenine cytosine thymine D cytosine thymine adenine 1.1.9 When red shorthorn cattle are crossed with white shorthorn cattle, the offspring have both red and white fur. This cross is an example of….. A Inheritance with multiple alleles B Incomplete dominance C Dihybrid cross D Co-dominance Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences/P2 6 com Limpopo PED/September 2022 1.1.10 The diagram below shows the genotypes of two parent plants and three of their offspring for a characteristic that is controlled by a dominant allele. Parents Plant 1 Plant 2 Rr Rr Offspring Plant 3 Plant 4 Plant 5 RR Rr rr Which of the plants have the same phenotype? A 1, 2 and 4 B 1, 2, 3 and 4 C 3 and 5 D 3, 4 and 5 (10 x 2) (20) 1.2 Give the correct biological term for each of the following descriptions. Write only the term next to the question number (1.2.1 to 1.2.8) in your ANSWER BOOK. 1.2.1 A factor/variable that is changed or manipulated during an investigation 1.2.2 The law that describes how alleles are separated from one another during the formation of gametes 1.2.3 A genotype consisting of different alleles for a specific trait 1.2.4 The complete disappearance of a species from earth 1.2.5 The splitting of the cytoplasm during cell division 1.2.6 An opening on hominid skulls through which the spinal cord passes 1.2.7 The region of a chromosome where two chromatids are attached to each other (7) Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences/P2 7 com Limpopo PED/September 2022 1.3 Indicate whether each of the statements in COLUMN 1 applies to A ONLY, B ONLY, BOTH A AND B or NONE of the items in COLUMN 2. Write A only, B only, both A and B, or none next to the question number (1.3.1 to 1.3.8) in the ANSWER BOOK. COLUMN 1 COLUMN 2 1.3.1 Genetic disorder linked to a sex A Haemophilia chromosome B Sickle-cell anaemia 1.3.2 The evidence used to support the A Mitochondrial DNA “Out of Africa” hypothesis by B Y-chromosome tracing the maternal lineage 1.3.3 Examples of reproductive A Breeding at different isolation mechanisms times of the year B Adaptation to different pollinators (3 x 2) (6) 1.4 The diagram below shows a process that occurs during meiosis. • 1.4.1 Name: (a) the process occurring in the diagram above. (1) (b) the phase in meiosis during which this process occurs. (1) 1.4.2 Identify the part marked Y. (1) 1.4.3 Describe the process mentioned in QUESTION 1.4.1 (a). (3) (6) Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences/P2 8 com Limpopo PED/September 2022 1.5 In cattle, black coat colour (B) is dominant to brown coat colour (b), and long horns (H) are dominant over short horns (h). Study the following Punnett square of the cross between a cow and a bull before answering the questions that follow. FEMALE → BH Bh bH bh MALE ↓ Bh X Bh Y Bh Bh 1.5.1 State why the example above represents a dihybrid cross. (2) 1.5.2 Give the genotype of the female parent (1) 1.5.3 Give the: (a) genotype of offspring X (2) (b) phenotype of offspring Y (2) 1.5.4 What percentage of the offspring will be black with long horns? Show your working out. (3) 1.5.5 Which principle of Mendel applies to dihybrid crosses only? (1) (11) [50] TOTAL SECTION A: 50 Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences/P2 9 com Limpopo PED/September 2022 SECTION B QUESTION 2 2.1 The diagram below shows different phases of meiosis in an organism. Y X Diagram Diagram I1 DiagramII2 Diagram M Z DiagramIII Diagram 3 2.1.1 Identify structure: (a) X (1) (b) Z. (1) 2.1.2 Give TWO observable reasons why chromosomes pair Y is regarded as being homologous. (2) 2.1.3 Identify the phases shown in diagrams 1, 2 and 3. (3) 2.1.4 List TWO events in meiosis that contribute to genetic variation. (2) (9) 2.2 A blue-eyed woman marries a man who is heterozygous for brown eyes. Brown eyes (B) are dominant over blue eyes (b). Use a genetic cross to show the possible genotypes and phenotypes of their children. (6) Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences/P2 10 com Limpopo PED/September 2022 2.3 The pedigree diagram below shows the inheritance of a genetic disease caused by a single gene. 1 2 3 4 5 KEY Unaffected Unaffected male female Affected male Affected female 2.3.1 Use individuals 2 and 5 to explain why this disease is a caused by a recessive allele on the X-chromosome. (5) 2.3.2 Use the letters Xn for the recessive allele and XN for the dominant allele to give the genotypes of individual: (a) 3 (1) (b) 4 (1) 2.3.3 What percentage of the daughters produced by individuals 3 and 4 would be affected? (1) (8) Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences/P2 11 com Limpopo PED/September 2022 2.4 A group of grade 12 learners conducted a survey to establish the number of learners with each blood group. The graph below shows the results of the survey. Percentage of learners with each blood group 50 45 Percentage of learners (%) 40 35 30 25 20 15 10 5 0 A B AB O Blood groups Blood groups 2.4.1 State TWO planning steps that should be considered before carrying out this investigation (2) 2.4.2 Which blood group has the lowest percentage of learners? (1) 2.4.3 Give ONE reason why the data from this investigation was represented using the above type of graph. (2) 2.4.4 What conclusion can be drawn from the results presented in the graph? (2) 2.4.5 The frequency of each blood group worldwide is shown in the table below Blood type Worldwide Frequency (%) O 45 A 40 B 11 AB 4 The learners expected their results to correspond with the results in the table, but they do not. Explain why the results of the learners’ investigation are not reliable. (2) (9) Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences/P2 12 com Limpopo PED/September 2022 2.5 The table below shows the skulls of fossils of different genera. GENERA SKULL BRAIN PERIOD OF VOLUME EXISTENCE (MILLION YEARS AGO) African ape 530 cm³ 8 mya Australopithecus 430cm³ 4–2,7 mya Homo erectus 850cm³ 2–0,4 mya Homo sapiens 1450cm³ 0,2 mya–present 2.5.1 How many million years ago did Homo erectus first appear? (1) 2.5.2 Calculate the difference in brain volume between Australopithecus and Homo sapiens. Show ALL calculations. (2) 2.5.3 State TWO advantages of a larger brain volume. (2) 2.5.4 Tabulate THREE visible differences between the skulls of Homo sapiens and the African ape. (7) 2.5.5 Describe TWO structural features of the body that correspond with the evolution to bipedalism. (4) (16) Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences/P2 13 com Limpopo PED/September 2022 2.6 Genetically modified organisms (GMOs) bring new hope for medical cures, promise to increase yields in agriculture and have the potential to help solve the world's pollution and resource crisis. There are also many objections to GMOs, some stating that they are expensive to produce and are a threat to biodiversity. 2.6.1 Give ONE reason why: (a) the initial cost of production of GMOs is high (1) (b) GMOs are considered a threat to biodiversity (1) (2) TOTAL QUESTION 2: [50] Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences/P2 14 com Limpopo PED/September 2022 QUESTION 3 3.1 Read the extract. Scientists have studied the appearance, genetics and behaviours of wolves and domesticated dogs to better understand what caused them to diverge thousands of years ago. Wolves began to evolve through a process in which people selectively bred individuals with desired traits and behaviours, such as reduced aggression and willingness to submit to human social structure. Scientists have discovered that some wolves had the genes to produce amylase and digest starch and benefited from the human food they were scavenging. Domesticated dogs produce much more amylase compared to wolves and this allows dogs to benefit from a high-starch diet of humans in a way that wolves never could. 3.1.1 Using the example given in the passage, describe how a population of wolves may have evolved to form the first population of dogs. (6) 3.1.2 Although all dogs are descendants of the wolf, the use of artificial selection has allowed humans to drastically alter the appearance of dogs. For centuries, dogs have been bred for various desired characteristics, leading to the creation of a wide range of dogs, from the tiny Chihuahua to the massive Great Dane. (a) Explain why all breeds of domestic dogs belong to the same species. (3) (b) Describe how artificial selection has led to the different breeds of domestic dogs. (3) (12) Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences/P2 15 com Limpopo PED/September 2022 3.2 The diagram below represents the changes in a population of bacteria as a result of exposure to an antibiotic over time. Diagram A Diagram B Key Low High Antibiotic resistance level 3.2.1 Explain, in terms of natural selection, the change in the proportion (6) of antibiotic resistant bacteria in the population in diagram B 3.2.2 Explain why antibiotic resistance can become a severe health (3) problem in hospitals (9) 3.3 Read the following extract. Since 1972, biologists Peter and Rosemary Grant have studied finch populations in the Galapagos Islands. They studied one finch population on an island called Daphne Major. The table below shows the data they collected over a period of 7 years. Year 1974 1975 1976 1977 1978 1979 1980 Rainfall (mm) - - 130 20 130 70 50 Number of finches 1 100 1 300 1 100 200 350 300 250 Small seeds (mg/m2) - 800 600 90 300 70 50 Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences/P2 16 com Limpopo PED/September 2022 3.3.1 Use the information in the table to draw a line graph to show the (6) number of finches from 1974 until 1980. 3.3.2 In which year were the largest drop in rainfall, number of seeds and (1) number of finches recorded? 3.3.3 Explain how the three events mentioned in QUESTION 3.3.2 are (4) related to each other. 3.3.4 When the number of finches decreased, there were still plenty of large seeds on the island. What does this tell you about the seed- eating habits of the finches that died? (1) (12) 3.4 The diagram below shows some processes that occur during protein synthesis. 3.4.1 Identify: (a) Molecule Y (1) (b) Organelle V (1) (c) Structure Z (1) 3.4.2 Give the sequence of nitrogenous bases for the first codon on Molecule Y (1, 2, 3). (1) Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences/P2 17 com Limpopo PED/September 2022 3.4.3 Give the correct order in which molecules P, Q, R and S would attach to molecule Y. (From left to right) (2) 3.4.4 Where in a cell does stage X occur? (1) 3.4.5 If the third nitrogenous base (A) of the DNA strand was replaced by G, describe how this would affect the protein that will form. (4) 3.4.6 Describe the process of transcription (6) (17) TOTAL QUESTION 3: 50 GRAND TOTAL: 150 Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. com ERRATUM: LFSC PREP PAPER 2 MARKING GUIDELINE 2022 ENGLISH 1.2.7 Centromere  1.2.8 Delete 1.4 1.4.1 (a) Crossing over (1) (b) Prophase (1) 1.4.2 Y - Chiasma (1) 1.4.3 - Homologous chromosomes/bivalents pair up - Each chromosome has 2 chromatids - Chromatids overlap/cross over - Genetic material is exchangedbetween non-sister chromatids - After the process of crossing-over chromosomes have genes from the homologous partner Max (3) (6)

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. com NATIONAL SENIOR CERTIFICATE GRADE 12 LIFE SCIENCES P2 SEPTEMBER 2022 MARKING GUIDELINES MARKS: 150 This memorandum consists of 11 pages

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences / P2 2 comLimpopo PED/ September 2022 MARKING GUIDELINE PRINCIPLES RELATED TO MARKING LIFE SCIENCES 2022 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 part of it is required Read all and credit relevant part. 4. If comparisons are asked for and descriptions are given Accept if 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 becomes correct again, resume credit. 9. Non-recognized abbreviations Accept if first defined in answer. If not defined, do not credit the unrecognised abbreviation but credit the rest of 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 recognizable, accept, provided it does not mean something else in Life Sciences or if it is out of context. 13. If common names given in terminology Accept, provided it was accepted at the National memo discussion meeting. 14. If only letter is asked for and only name is given (and vice versa) No credit. Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences / P2 3 comLimpopo PED/ September 2022 MARKING GUIDELINE 15. If units are not given in measurements Memorandum will allocate marks for units separately, except where it is already given in the question. 16. Be sensitive to the sense of an answer, which may be stated in a different way. 17. Caption Credit will be given for captions to all illustrations (diagrams, graphs, tables, etc.) except where it is already given in the question. 18. Code-switching of official languages (terms and concepts) A single word or two that appears 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 Downloaded f rom St anmorephysics. NSC Life Sciences / P2 4 comLimpopo PED/ September 2022 MARKING GUIDELINE SECTION A QUESTION 1 1.1 1.1.1 D 1.1.2 B 1.1.3 B 1.1.4 C 1.1.5 A 1.1.6 C 1.1.7 B 1.1.8 C 1.1.9 D 1.1.10 B (10 x 2) (20) 1.2 1.2.1 Independentvariable 1.2.2 (Law of) segregation 1.2.3 Heterozygous 1.2.4 Extinction 1.2.5 Cytokinesis 1.2.6 Foramen magnum 1.2.7 Centromere (7) 1.3 1.3.1 A only 1.3.2 A only 1.3.3 Both A and B (3 x 2) (6) 1.4 1.4.1 (a) Crossing over (1) (b) Prophase (1) 1.4.2 Y - Chiasma (1) 1.4.3 - Homologous chromosomes/bivalents pair up - Each chromosome has 2 chromatids - Chromatids overlap/cross over - Genetic material is exchangedbetween non-sister chromatids - After the process of crossing-over chromosomes have genes from the homologous partner Max (3) (6) Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences / P2 5 comLimpopo PED/ September 2022 MARKING GUIDELINE 1.5 1.5.1 This is a Dihybrid cross: It is a cross between two individuals with two observed traits/ coat colour and horn length that are controlled by two distinct genes. (2) 1.5.2 BbHh  (1) 1.5.3 (a) BBHh  (2) (b) BBhh = black coat colour; short horns  (2) 1.5.4 BBHh = 4 8 x Black coat; Long horns BbHh = 4  Bbhh = 4 8 x Black coat; Short horns BBhh = 4 8 x 100 = 50 % 16 (3) 1.5.5 (Principle of) Independent Assortment (1) (11) TOTAL SECTION A: 50 Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences / P2 6 comLimpopo PED/ September 2022 MARKING GUIDELINE SECTION B QUESTION 2 2.1 2.1.1 (a) Cell membrane  (b) Spindle fibres (2) 2.1.2 The chromosomes are of the: - Same size - Same shape - Same length Any (2) (Mark first TWO only) 2.1.3 1 - Metaphase 1 2 - Prophase 1 3 - Metaphase 2 (3) 2.1.4 - Crossing over  (2) - Random arrangement of chromosomes (Mark first TWO only) (9) 2.2 P1/parent phenotype blue eyes x brown eyes genotype bb x Bb  Meiosis G/gametes b, b x B, b Fertilisation F1/offspring genotype Bb, bb, Bb & bb  phenotypes 2 blue eyes and 2 brown eyes genotypes Bb, bb, Bb, bb Parents and offspring/P1 and F1 Meiosis and fertilisation Any (6) OR P1/parent phenotype blue eyes x brown eyes 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/offspring: phenotype 2 blue eyes and 2 brown eyes Parents and offspring/P1 and F1 Meiosis and fertilisation Any (6) Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences / P2 7 comLimpopo PED/ September 2022 MARKING GUIDELINE 2.3 2.3.1 - Individual 5 is an affected male✓ and - He must have one Y chromosome✓ and - the recessive allele on the X chromosome✓ - which he would have inherited from his mother (individual 2) ✓ - But she does not have the disorder✓, which means it is caused by a recessive allele (5) 2.3.2 (a) 3: XnXn✓ (b) 4: XNY ✓ (2) 2.3.3 0% ✓ (1) (8) 2.4 2.4.1 Planning: • Get permission from all stakeholders/ the learners and their parents  • Decide on the sample size/ composition/ participants  • Decide on the method to use to determine the blood groups/ ensure that the learners know their blood groups  • Determine the apparatus and equipment needed to test for the different blood groups  • Design a record sheet  • Set a date/ time for the investigation  • Arrange venue  (Mark first TWO only) Any (2) 2.4.2 B (1) 2.4.3 Represent separate/discrete/different entities/blood groups /units OR Discontinuous variable / No  intermediate groups (2) 2.4.4 45 %  /Majority of the sample group have blood group A OR 10 %  /Minority of the sample group have blood group B OR 20 % of the sample group have blood group AB OR 35 % of the sample group have blood group O (2) 2.4.5 The sample group was very small/ only one group of learners from an entire school and is therefore not representative of the world population  (2) (9) Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences / P2 8 comLimpopo PED/ September 2022 MARKING GUIDELINE 2.5 2.5.1 2 mya (1) 2.5.2 1450 cm3 – 430 cm3 (1450 – 430)  cm3 = 1020 cm3 (2) 2.5.3 Have better co-ordination of movement Process large amount of information Processing information faster Development of spoken and written languages to communicate (Mark first TWO only) (2) 2.5.4 Table (1) Homo sapiens African ape/Gorilla Large cranium Small cranium Smaller jaw Bigger jaw Non-prognathous Prognathous Smaller teeth/canines Bigger teeth/canines Brow ridge reduced/ Brow ridge large/ absent pronounced Well-developed chin Less developed chin (Mark first THREE only) (6) (7) 2.5.5 • The foramen magnum moved from a backwards position to a more forward position in the modern human • The curvature of the spinechanged from C-shaped to S-shaped • The pelvis changed from long and narrow to wider and shorter.  (Mark first TWO only) (4) (16) 2.6 2.6.1 (a) new equipment is expensive labour intensive many clinical trialsmust be done/long time to produce a safe product (Mark first ONE only) Any (1) (b) may easily pollinate non-GM crops/may mate with non-GM animals they might out-compete the naturally occurring organisms (Mark first ONE only) Any (1) (2) TOTAL QUESTION 2: [50] Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences / P29 comLimpopo PED/ September 2022 MARKING GUIDELINE QUESTION 3 3.1 3.1.1 • there is variation in the wolves • in terms of their behaviour/ reduced aggression • and genetics / ability to produce amylase/ digest starch • A population of less aggressive/more tame wolves✓ were separated✓from the original wild population • They became scavengers✓ around human settlements because they could digest the starch in human food ✓ • and were more suited for survival ✓amongst a human population • The genes for producing more amylase were passed on to their offspring✓ • The next generation had a higher proportion of individuals with the favourable characteristic ✓ Max 6 (6) 3.1.2 (a) They can interbreedwith different domestic dog breeds to produce fertile offspring (3) (b) Humans chose desired characteristics✓ and bred dogs with those phenotypes and genotypes to create dogs that suit their needs ✓/ e.g. hunters, companions, helpers. (3) (12) 3.2 3.2.1 - Due to a mutation - some bacteria are resistant to the antibiotic and - others are not - There is a large degree of variation in the bacteria population - When the antibiotic was first used, - the non-resistant bacteria died  - The resistant bacteria survived - to reproduce thereby - increasing the population of antibiotic-resistant bacteria Any Max 6 (6) Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences / P2 10 comLimpopo PED/ September 2022 MARKING GUIDELINE 3.2.2 - Overuse/ frequent use of antibiotics - may lead to the development of antibiotic resistant strains of bacteria /Infections caused by these bacteria are no longer affected by the antibiotic treatment - Antibiotic resistance leads to higher medical costs, prolonged hospital stays, and increased mortality.  (3) (9) 3.3 3.3.1 Number of finches from 1974 to 1980 Number of finches 1400 1200 1000 800 600 400 200 0 1974 1975 1976 1977 1978 1979 1980 Time (years) Rubric for awarding marks for the graph Correct type of graph 1 Title of graph 1 Correct label for X and Y-axes 1 Correct scale and units for X and 1 Y-axes Plotting points 1: 1 - 4 correctly plotted 2: All 7 correctly plotted NOTE: If the wrong type of graph is drawn: marks will be forfeited for "correct type of graph" as well as for the ''joining of points''. (6) 3.3.2 1977 (1) 3.3.3 A drop in rainfall/ drought causes a drop in seed production/plant growth causing less food to support fewer finches (4) 3.3.4 the beaks of these finches were too small/ not strong enough to be able to eat the large seeds (1) (12) Copyright reserved Please turn over

Downloaded from hlayiso.com Downloaded f rom St anmorephysics. NSC Life Sciences / P2 11 comLimpopo PED/ September 2022 MARKING GUIDELINE 3.4 3.4.1 (a) Molecule Y: mRNA (b) Organelle V: ribosome (c) Structure Z: nuclear membrane (3) 3.4.2 First codon on molecule Y: AGU (1) 3.4.3 R; S; P; Q (must be in correct order)  (2) 3.4.4 Cytoplasm  (1) 3.4.5 If nitrogenous base A is replaced by G, the codon will change to AGC  This will code for another anticodon/ UCA instead of AGU And may result in coding for another amino acid which may change the protein that is formed (4) 3.4.6 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 RNA nucleotides from the nucleoplasm.  The mRNA is complementary to the DNA.  mRNA now has the coded message for protein synthesis  (Any 6) (6) (17) TOTAL QUESTION 3: 50 GRAND TOTAL: 150 Copyright reserved Please turn over