Life Sciences Grade 12 P2 Gauteng Mock 2019 QP (Eng)

Downloaded from hlayiso.com GAUTENG DEPARTMENT OF EDUCATION PREPARATORY EXAMINATION 2019 10832 LIFE SCIENCES PAPER 2 TIME: 2½ hours MARKS: 150 18 pages P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 2 (Paper 2) 10832 / 19 GAUTENG DEPARTMENT OF EDUCATION PREPARATORY EXAMINATION – 2019 LIFE SCIENCES (Paper 2) TIME: 2½ hours MARKS: 150 INSTRUCTIONS AND INFORMATION Read the following instructions carefully before answering the questions. 1. Answer ALL the questions. 2. Write ALL the answers in the ANSWER BOOK. 3. Start 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. Present your answers according to the instructions of each question. 6. Do ALL drawings in pencil and label them in blue or black ink. 7. Draw diagrams, tables or flow charts only when asked to do so. 8. The diagrams in this question paper are NOT necessarily drawn to scale. 9. Do NOT use graph paper. 10. You must use a non-programmable calculator, protractor and a compass, where necessary. 11. Write neatly and legibly. P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 3 (Paper 2) 10832 / 19 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 – 1.1.9) in your ANSWER BOOK, for example 1.1.10 D. 1.1.1 Below is a list of fossils discovered in South Africa. (i) Mrs Ples (ii) Taung child (iii) Little foot (iv) Karabo Which ONE of the following combinations of fossils is classified in the genus Australopithecus? A (i), (ii) and (iii) only B (i), (ii), (iii) and (iv) C (i) and (ii) only D (ii), (iii) and (iv) only 1.1.2 During cloning, a nucleus is taken from a somatic cell and introduced into … A a sperm cell. B an ovum. C a zygote. D another somatic cell. 1.1.3 A man who has haemophilia … A has inherited a recessive allele from his father. B has inherited a dominant allele from his mother. C can pass a recessive allele to his daughter. D can pass a dominant allele to his daughter. P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 4 (Paper 2) 10832 / 19 1.1.4 A freshly smoked cigarette was found near the body of a murdered woman. Forensic specialists made a DNA profile from traces of saliva (not belonging to the murdered victim) found on the cigarette. Four suspects were required to give DNA samples to forensic officers and the following profiles were made: Saliva Who is most likely the murderer? A Ben B Jane C Adam D Donald 1.1.5 Which ONE of the following indicates where the DNA molecule is likely to separate during DNA replication? A Cytosine and guanine B Phosphate ions and deoxyribose C Ribose and adenine D Ribose and thymine P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 5 (Paper 2) 10832 / 19 1.1.6 An autosomal genetic disorder is caused by a dominant allele R. Consider the following crosses. (i) rr x Rr (ii) rr x RR (iii) Rr x Rr (iv) Rr x RR Which ONE of the following combinations of crosses can result in offspring without the disorder? A (i) and (ii) only B (i) and (iii) only C (i) only D (ii) and (iv) only 1.1.7 Studies of four excavation sites in the same general region of Africa yielded the following data on primate fossils. Primate skeleton Cranial size Relative length of arms and number (cm3) legs I 290 arms longer than legs II 1 300 arms shorter than legs III 600 arms same length as legs IV 1 000 arms shorter than legs Which TWO individuals are probably bipedal? A I and II. B I and III. C I and IV. D II and IV. P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 6 (Paper 2) 10832 / 19 1.1.8 Study the phylogenetic tree below. Which two species are LEAST related? A Pygmy hippopotamus and blue whale B White-tailed deer and wild boar C Blue whale and white-tailed deer D Alpaca and blue whale 1.1.9 Study the pedigree diagram below which shows the inheritance of colour-blindness caused by a recessive allele in humans. homozygous Key Normal vision Normal vision Which offspring show the INCORRECT representation of the inherited trait? A I, II and III B I, IV and V C I, III and VII D I, II, III, VI and VII (9 x 2) (18) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 7 (Paper 2) 10832 / 19 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 – 1.2.8) in the ANSWER BOOK. 1.2.1 More than two alleles for the same gene 1.2.2 A section of DNA that carries the code for a particular trait 1.2.3 A genetic cross in which both alleles are expressed equally in the phenotype 1.2.4 Cells that can differentiate into many other cell types 1.2.5 A process by which genetically identical organisms are formed using biotechnology 1.2.6 Organelle outside the nucleus of animal cells that contain DNA 1.2.7 A genotype having two non-identical alleles for a trait 1.2.8 A mapping of the exact position of all the genes in all the chromosomes within a cell (8 x 1) (8) 1.3 Indicate whether each of the descriptions in COLUMN I apply to A ONLY, B ONLY, BOTH A AND B or NONE of the items in COLUMN II. Write A only, B only, both A and B or none next to the question number (1.3.1 – 1.3.3) in the ANSWER BOOK. COLUMN I COLUMN II 1.3.1 Contains uracil A: DNA B: RNA 1.3.2 Cause of Down syndrome A: Gene mutation B: Extra copy of chromosome number 23 1.3.3 An allele for one gene could appear in A: Dihybrid cross the same gamete with any of the B: Mendel’s law of alleles of another gene independent assortment (3 x 2) (6) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 8 (Paper 2) 10832 / 19 1.4 The diagram below represents a process involving DNA. 1.4.1 Identify the process illustrated in the diagram above. (1) 1.4.2 Identify the monomer X. (1) 1.4.3 Using the key provided, give the names for 1 and 2 respectively. (2) 1.4.4 What is the natural shape of the molecule represented? (1) 1.4.5 Name the type of bond that is formed between 1 and 2. (1) (6) . P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 9 (Paper 2) 10832 / 19 1.5 The diagram below shows different phases of meiosis in an organism. B A Diagram I Diagram II C D Diagram III 1.5.1 Provide labels for A, B and D, respectively. (3) 1.5.2 Give TWO observable reasons why chromosomes B above are regarded as homologous. (2) 1.5.3 Identify the phases shown in Diagrams I, II and III, respectively. (3) 1.5.4 Give a reason for identifying the phase in Diagram III. (2) 1.5.5 Identify TWO events in meiosis that contribute to genetic variation. (2) (12) TOTAL SECTION A: 50 P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 10 (Paper 2) 10832 / 19 SECTION B QUESTION 2 2.1 Study the DNA base triplets 1, 2 and 3 below. Base triplet 1 Base triplet 2 Base triplet 3 GTC AAG CCT The table below shows the RNA codons that code for different amino acids. CODON AMINO ACID UUC Phenylalanine AUC Isoleucine AAU Asparagine GAA Glutamic acid GUA Valine CAG Glutamine CAU Histidine GGA Glycine 2.1.1 Write down the three bases of the DNA base triplet that codes for glycine. (1) 2.1.2 In base triplet 2 the first adenine was replaced by T as a result of a mutation. Describe how this mutation will affect the protein that will be formed. (3) 2.1.3 State TWO ways in which the events of transcription in protein synthesis are different from that of DNA replication. (2 x 2) (4) (8) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 11 (Paper 2) 10832 / 19 2.2 The diagram below illustrates the process of translation in protein synthesis. W amino acid X Y Z Identify: 2.2.1 The bond formed at W (1) 2.2.2 Structure X (1) 2.2.3 The anticodon that matches with Z (1) 2.2.4 Organelle Y (1) (4) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 12 (Paper 2) 10832 / 19 2.3 A set of triplets, two of which were known to be genetically identical, were separated at birth and brought up under very different circumstances. At the age of 23 the following data was recorded. Trait Tom Dick Harry Height (cm) 188 180 188 Weight (kg) 72 87 87 Blood Type O AB O IQ (measure of intelligence) 138 142 125 2.3.1 Which two boys are genetically identical? (1) 2.3.2 Give a reason for your answer to Question 2.3.1. (1) 2.3.3 If the three boys were reunited and were attempting to locate their parents, what would be the only possible blood types of each of their parents? (2) (4) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 13 (Paper 2) 10832 / 19 2.4 In an experiment, rats with white coats (W) were crossed with rats with black coats (B). The F1 were all grey. 2.4.1 What type of dominance is shown in the genetic cross above? (1) 2.4.2 If the grey offspring were interbred, use a genetic cross to determine the genotypes and phenotypic ratio of their offspring. (6) (7) 2.5 For flower colour in sweet-pea plants, the allele (A) for purple flowers is dominant over the allele (a) for white flowers. For the shape of the pollen grains, the allele (B) for long pollen grains is dominant over the allele (b) for round pollen grains. Plant X with the genotype AABb was crossed with plant Y that had white flowers and round pollen grains. 2.5.1 Identify the phenotype of plant X. (1) 2.5.2 Write down all the possible gametes of plant Y. (2) 2.5.3 Write down all the expected phenotypes of the offspring in a cross between plant X and Y. (2) (5) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 14 (Paper 2) 10832 / 19 2.6 The table below shows the mass gain of two babies during an investigation on the type of milk used for feeding the babies until they were one year old. One was fed on milk from a genetically modified cow and the other on milk from a normal cow. Both babies were two months old and had the same mass at the beginning of the study. Mass of babies (kilograms) Time Milk source from Milk source from (months) genetically modified cows normal cows 2 4,0 4,0 4 6,7 5,8 6 9,0 8,0 8 12,0 10,5 10 14,0 11,0 12 15,8 11,5 [Adapted from Woman’s Weekly 2009] 2.6.1 Identify: (a) ONE independent variable (1) (b) The dependent variable (1) 2.6.2 Identify ONE factor that was kept constant in this investigation. (1) 2.6.3 Calculate the percentage increase in mass over the period of the investigation, for the baby fed on genetically modified milk. Show all calculations. (3) 2.6.4 Draw a bar graph to show the trend in mass gain of both babies, from ages 2 – 8 months. (6) (12) [40] P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 15 (Paper 2) 10832 / 19 QUESTION 3 3.1 There are different explanations for evolution. 3.1.1 Describe the TWO laws used by Lamarck to explain evolution. (4) 3.1.2 Describe punctuated equilibrium. (4) 3.1.3 Darwin explained evolution through natural selection. Tabulate TWO differences between artificial selection and natural selection. (5) (13) 3.2 Read the following extract following a survey done by naturalist Colin Donihue on the effects of hurricane Irma on the populations of an endemic species of lizard on two islands in the West Indies. Colin and his team visited the islands after hurricane Irma had struck. They captured as many as possible of the endemic lizards, Anolis scriptus. The captured lizards all had the following features: Bigger toepads, longer arms and shorter hind legs. The first two observations made sense as these were known to increase clinging ability in Anolis but the third did not. Wouldn’t longer hind legs cling to vegetation better? – So why did more lizards with shorter hind legs survive? Colin realized that the longer hind legs of the lizards, once they lost their grip on a branch, acted as ‘sails’, catching the wind, and thus carrying the lizard away into the sea. 3.2.1 What is the scientific name of the lizard that was studied? (1) 3.2.2 Give TWO characteristics that were favourable for the survival of the lizard. (2) 3.2.3 Explain ONE characteristic that was unfavourable for the survival of the lizard. (2) (5) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 16 (Paper 2) 10832 / 19 3.3 As a result of a mutation, bacteria with three varieties of cell wall exist as shown below. cell wall with cell wall with round spikes square spikes cell wall with triangular spikes An antibiotic destroys the bacteria by binding with it. The antibiotic has two binding sites, one triangular and the other square. Use Darwin’s theory of evolution through natural selection to explain why the bacteria with round spikes on their cell walls will increase in proportion in future generations. (6) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 17 (Paper 2) 10832 / 19 3.4 The diagram below shows the skulls of three organisms. 3.4.1 Label part X and the type of teeth at Y. (2) 3.4.2 Explain the significance of the location of structure X in organism C. (3) 3.4.3 Which of the skulls (A, B or C) belongs to: (a) An australopithecine (1) (b) A quadripedal primate (1) 3.4.4 Explain how the change in the skull from B to C could indicate a change in intelligence. (3) 3.4.5 Describe the significance of the shape of each of the following as a trend in human evolution: (a) Spine (2) (b) Shape of the pelvis (2) 3.4.6 Describe the significance of Homo erectus to the ‘Out of Africa’ hypothesis. (2) (16) [40] TOTAL SECTION B: 80 P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 18 (Paper 2) 10832 / 19 SECTION C QUESTION 4 The formation of new species contributes to an increase in biodiversity. Describe how speciation occurs through geographic isolation and describe FOUR reproductive isolating mechanisms that keep species separate. Content: (17) Synthesis: (3) [20] NOTE: NO marks will be awarded for answers in the form of flow charts, tables or diagrams. TOTAL SECTION C: 20 TOTAL: 150 END