Life Sciences Grade 12 P2 NSC June 2015 Question Paper (Eng)

Downloaded from hlayiso.com SENIOR CERTIFICATE EXAMINATION LIFE SCIENCES P2 2015 MARKS: 150 TIME: 2½ hours This question paper consists of 14 pages. Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 2 DBE/2015 SCE 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. ALL drawings must be done in pencil and labelled in blue or black ink. 7. Draw diagrams, flow charts or tables 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. Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 3 DBE/2015 SCE SECTION A QUESTION 1 1.1 Various options are given as possible answers to the following questions. Choose the answer and write only the letter (A to D) next to the question number (1.1.1 to 1.1.8) in the ANSWER BOOK, for example 1.1.9 D. 1.1.1 Humans have 46 chromosomes in each somatic cell. Each gamete produced will have … A 22 autosomes and 1 gonosome. B 21 autosomes and 2 gonosomes. C 23 autosomes. D 23 gonosomes. 1.1.2 The table below shows the results of the F 1 generation after an investigation into the inheritance of eye colour in fruit flies was carried out. EYE COLOUR NUMBER OF FLIES Red 182 White 61 The genotypes of the parents were … A RR x Rr. B Rr x rr. C Rr x Rr. D RR x rr. 1.1.3 Which ONE of the following is TRUE about genes? Genes are … A codes for a particular characteristic. B made up of amino acids. C made up of RNA. D found in a ribosome. 1.1.4 Which ONE of the following is used to produce genetically identical individuals? A Stem cell research B Genetic modification C Cloning D DNA profiling Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 4 DBE/2015 SCE QUESTIONS 1.1.5 and 1.1.6 are based on the pedigree diagram below. The pedigree diagram shows the inheritance of blood groups in a family. The blood groups of the individuals are represented by the letters. OO A B 1 B O AB 2 KEY Female Male A PEDIGREE DIAGRAM 1.1.5 Which ONE of the following represents the genotype and phenotype of individual number 1 above? A ii and blood group O B IAi and blood group A C IAi and blood group O D IBi and blood group B 1.1.6 If individual 2 has a child with blood group AB, then her partner could only have blood group … A AB. B A. C O. D B. Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 5 DBE/2015 SCE 1.1.7 Which ONE of the following is CORRECT with regard to the structure of DNA and RNA? A RNA is double-stranded and DNA is single-stranded. B RNA contains uracil and DNA contains thymine. C RNA is a very long molecule while DNA is a short molecule. D RNA forms a double helix while DNA does not. 1.1.8 Which ONE of the following represents molecules that make up a single nucleotide? A Phosphate, sugar and a nitrogenous base B Sugar, protein and phosphate C Nitrogenous base, phospholipid and sugar D Adenine, sugar and a nitrogenous base (8 x 2) (16) 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 1.2.9) in the ANSWER BOOK. 1.2.1 The type of inheritance involving two alleles of a gene that are not dominant over one other 1.2.2 Characteristics controlled by genes which are located on the sex chromosomes 1.2.3 Chromosomes that are similar in structure and code for the same characteristics 1.2.4 The monomers/building blocks of proteins 1.2.5 The type of inheritance involving alleles that equally determine the phenotype of heterozygous offspring 1.2.6 Undifferentiated cells which are able to develop into any other types of cells 1.2.7 Intermediate fossils showing features of both more primitive and more advanced organisms 1.2.8 An allele that is expressed phenotypically only in the homozygous condition 1.2.9 A genetic cross involving one characteristic only (9) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 6 DBE/2015 SCE 1.3 Indicate whether each of the statements in COLUMN I applies 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 to 1.3.4) in the ANSWER BOOK. COLUMN I COLUMN II 1.3.1 Discovered the fossil of A: Raymond Dart Australopithecus sediba B: Ron Clark 1.3.2 Example of continuous variation A: Height B: Blood groups 1.3.3 Pronounced brow ridges A: African apes B: Homo sapiens 1.3.4 Discovered the structure of A: Watson DNA B: Crick (4 x 2) (8) 1.4 In tomato plants the allele for red fruit (R) is dominant over the allele for yellow fruit (r). The allele for tallness (T) is dominant over the allele for shortness (t). Plant A, which is heterozygous for red fruit and homozygous tall, was crossed with Plant B, which has yellow fruit and is short. 1.4.1 Write down the genotype of: (a) Plant A (1) (b) Plant B (1) 1.4.2 Write down ALL the possible genotypes of the gametes of plant A. (2) 1.4.3 Name the phenotype of an offspring having the genotype: (a) Rrtt (1) (b) RrTt (1) 1.4.4 Plant B was then crossed with another plant (Plant C) and all the offspring had red fruit and were tall. Use this information to write down the genotype of Plant C. (2) (8) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 7 DBE/2015 SCE 1.5 The diagram below shows cells of an organism in one of the phases of meiosis. A B E C D A PHASE OF MEIOSIS 1.5.1 Which phase of meiosis is represented in the diagram? (1) 1.5.2 Give the LETTER and NAME of the part that: (a) Is responsible for the formation of the spindle fibres (2) (b) Carries the genetic information (2) (c) Holds the chromatids together (2) 1.5.3 State the number of chromosomes that would be present in each of the cells of this organism: (a) At the beginning of meiosis (1) (b) In a gamete of this organism (1) (9) TOTAL SECTION A: 50 Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 8 DBE/2015 SCE SECTION B QUESTION 2 2.1 Diagram 1 shows variation in a species of fish living in a lake. There was a rocky island that extended across the whole length of the lake, but it was under water due to the high water level. The fish were therefore able to move freely throughout the lake. Diagram 2 shows the same lake many years later. A drought had caused the level of the water in the lake to drop so that the rocky island in the centre separated the lake into two smaller lakes, A and B, for a long period of time. Diagram 1 Rocky island Diagram 2 Lake A Lake B FISH POPULATION IN A LAKE 2.1.1 Define population. (2) 2.1.2 State FOUR possible causes of the variation in the fish population in Diagram 1. (4) 2.1.3 Eventually, as shown in Diagram 2, lake A and lake B contained two different species of fish. (a) Name the process that resulted in the fish population becoming two different species. (1) (b) Explain how the new species was formed. (6) (13) 2.2 A grey (G) male rabbit was mated with an albino (g) female rabbit. The entire F 1 generation was grey. Use a genetic cross to show the phenotypic ratio of their offspring if one of the males of the F 1 generation was mated with an albino female. (7) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 9 DBE/2015 SCE 2.3 The diagram below shows the process of protein synthesis. Y W Z X Process B Process A PROTEIN SYNTHESIS 2.3.1 Identify the following molecules: (a) W (1) (b) Y (1) 2.3.2 Name the part of protein synthesis indicated by process A. (1) 2.3.3 Describe how a mutation on molecule W will affect the structure of the protein formed by process B. (4) 2.3.4 The following sequence represents a part of the nitrogenous base sequence on molecule X. AGA AUG GGA triplet 1 triplet 2 triplet 3 (a) Write down the base sequence of the anticodon of triplet 1 shown above. (1) (b) The table below shows the amino acids that correspond with different DNA codes. AMINO ACID DNA CODE Arginine TCT Glycine CCT Methionine TAC Write down the correct sequence of amino acids for triplets 1 (3) to 3. (11) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 10 DBE/2015 SCE 2.4 The graph below represents the results of an investigation which compares the conviction (number of people found guilty) of criminals with the use of DNA evidence and without the use of DNA evidence from 1989 to 2003. COMPARISON OF THE CONVICTIONS WITH THE USE OF DNA EVIDENCE AND WITHOUT THE USE OF DNA EVIDENCE, FROM 1989 TO 2003 50 Number of people found guilty 40 Convictions with DNA 30 evidence (per 1 000 arrests) 20 Convictions without DNA 10 evidence 0 1989 1991 1993 1995 1997 1999 2001 2003 Year [Adapted from http://www.mindfully.org] 2.4.1 Formulate a hypothesis for this investigation. (2) 2.4.2 State the dependent variable in this investigation. (1) 2.4.3 How many more successful convictions per 1 000 arrests were made in 2003 with the use of DNA evidence? Show ALL calculations. (2) 2.4.4 A DNA database is a collection of the DNA profiles of all the citizens of a country. Explain how you would use the information in the graph to convince the government to create a DNA database. (4) (9) [40] Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 11 DBE/2015 SCE QUESTION 3 3.1 The photographs of two butterflies are provided below. Both butterflies live in the same habitat and are preyed on by predators. Although these butterflies are very similar in appearance they are two separate biological species. Amauris ochlea has an unpleasant taste while Hypolimnas deceptor does not have an unpleasant taste. Amauris ochlea Hypolimnas deceptor TWO SPECIES OF BUTTERFLY [From http://www.biodiversityexplorer.org.] 3.1.1 Explain why most predators are less likely to feed on Hypolimnas deceptor. (3) 3.1.2 Use Darwin's theory of evolution through natural selection to explain the evolution of the Hypolimnas deceptor butterfly. (6) 3.1.3 State ONE way in which natural selection differs from artificial selection. (2) (11) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 12 DBE/2015 SCE 3.2 The diagram below shows possible relationships between members of the family Hominidae. POSSIBLE RELATIONSHIPS BETWEEN HOMINIDS Present Homo sapiens Time (million years ago) Homo erectus Australopithecus robustus Australopithecus boisei Homo habilis Australopithecus africanus Australopithecus afarensis [Adapted from http://www.ideacentre.org] 3.2.1 What is the name given to the type of diagram above? (1) 3.2.2 How many of each of the following are represented in the diagram? (a) Genera (1) (b) Species (1) 3.2.3 Explain why A. robustus and A. boisei are more closely related than A. boisei and A. afarensis. (2) 3.2.4 Which of the hominids in the diagram above is considered to have been the first to use tools? (1) 3.2.5 Name TWO Australopithecus fossils found in South Africa. (2) 3.2.6 Explain how the location and the age of Homo fossils are used as evidence for the 'Out of Africa' hypothesis. (3) (11) Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 13 DBE/2015 SCE 3.3 The diagrams below represent parts of the skeletons of an African ape and a human. Diagrams A and B are drawn to scale. DIAGRAM A DIAGRAM B DIAGRAM C DIAGRAM D SKELETON PARTS OF AFRICAN APE AND HUMAN 3.3.1 Write down the LETTERS only of the diagrams (A–D) that represent bipedal organisms. (2) 3.3.2 Explain how the shape of the pelvis contributes to bipedalism. (2) 3.3.3 Explain the significance of the position of the foramen magnum in the skulls in diagram A and in diagram B. (4) 3.3.4 Tabulate THREE visible differences between the jaws/teeth of the skulls labelled A and B that indicate trends in human evolution. (7) 3.3.5 State THREE physical characteristics of the forelimb/upper limb that humans share with African apes. (3) (18) [40] TOTAL SECTION B: 80 Copyright reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 14 DBE/2015 SCE SECTION C QUESTION 4 Describe TWO types of mutations and how they lead to altered characteristics in FOUR genetic disorders you have studied. Content: (17) Synthesis: (3) NOTE: NO marks will be awarded for answers in the form of tables, flow charts or diagrams. TOTAL SECTION C: 20 GRAND TOTAL: 150 Copyright reserved