Life Sciences Grade 12 P2 Gauteng Mock 2016 Question Paper

Downloaded from hlayiso.com GAUTENG DEPARTMENT OF EDUCATION PREPARATORY EXAMINATION 2016 10832 LIFE SCIENCES SECOND PAPER MARKS: 150 TIME: 2½ hours 19 pages 3 P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 2 (Second Paper) 10832/16 GAUTENG DEPARTMENT OF EDUCATION PREPARATORY EXAMINATION LIFE SCIENCES (Second Paper) 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. 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 may 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 (Second Paper) 10832/16 SECTION A QUESTION 1 1.1 Various options are given 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. – 1.1.10) in the ANSWER BOOK, for example 1.1.11 D. 1.1.1 Which of the following is the correct base-pairing in DNA? A G-C, A-T B T-U, A-G C G-T, A-C D G-C, A-U 1.1.2 A researcher prepared a pedigree diagram (family tree) to trace a genetic disorder in a family. KEY Male has the genetic disorder. Female has the genetic disorder. Female does not have the genetic disorder. How could the allele that causes the condition best be described? A Co-dominant B Dominant C Recessive D Sex-linked 1.1.3 How many sex chromosomes does a normal human female inherit from her mother? A 1 B 2 C 23 D 46 P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 4 (Second Paper) 10832/16 1.1.4 Which of the following is true of a mutation, that produces an allele that is dominant? A It would be expected to cause death. B It would not affect a population at all. C It would give an observable functional phenotype in a heterozygous genotype. D It would give an observable functional phenotype only in a homozygous genotype. 1.1.5 The diagrams below are an artist’s impression of the appearance of several human or related species. The diagrams are drawn to scale. 1 2 3 4 List the diagrams in order from the most primitive to the least primitive. A 3, 1, 2, 4 B 2, 3, 4, 1 C 3, 2, 1, 4 D 3, 4, 2, 1 1.1.6 By whom and where was the famous Australopithecus sediba fossil found? A Lee Burger at ‘Cradle of Mankind’ B Robert Broom at ‘Cradle of Mankind’ C Raymond Dart at Taung D Louis and Mary Leaky in Tanzania P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 5 (Second Paper) 10832/16 1.1.7 The diagrams represent one pair of homologous chromosomes during meiosis. Crossing over is about to take place. 1 2 3 4 The genotypes that are produced in the chromatids numbered 1 – 4 after crossing over has taken place are … . A ABC, abC, ABc, abc B ABC, aBC, Abc, abc C ABC, ABC, abc, abc D ABC, aBc, Abc, abc 1.1.8 A scientist studying the inheritance of coat colour in a herd of shorthorn cattle performed the following cross: X The results of the cross is shown in the table below. Phenotype Offspring number White coat 0 Red coat 0 Red and white coat (Roan) 157 Total 157 Of which type of inheritance was the roan coat colour a result? A Incomplete dominance B Complete dominance C Heterozygous parents D Co-dominance P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 6 (Second Paper) 10832/16 1.1.9 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, 3 and 4 C 2, 3 and 4 D 1, 2, 3 and 4 1.1.10 Name the phase of meiosis represented in the diagram below. A Metaphase I B Anaphase I C Telophase II D Anaphase II (10x2) (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 – 1.2.8) in your ANSWER BOOK. 1.2.1 Site of DNA replication and transcription 1.2.2 Remains of organisms that existed millions of years ago 1.2.3 A block of DNA on a chromosome that codes for a particular characteristic 1.2.4 Having a face where the jaws project outwards 1.2.5 Arrangement of teeth on a jaw P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 7 (Second Paper) 10832/16 1.2.6 Individual with two copies of the same allele for a particular characteristic 1.2.7 The act of walking on all four limbs 1.2.8 Non-separation of chromosomes during meiosis (8x1) (8) 1.3 Indicate whether each of the descriptions 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 – 1.3.4) in the ANSWER BOOK. COLUMN I COLUMN II 1.3.1 Consists of the nucleotide bases: A: DNA Adenine, Guanine, Cytosine and B: RNA Uracil 1.3.2 Sex-linked condition where blood fails A: Haemophilia to clot properly B: Albino 1.3.3 A white flower is crossed with a red A: Incomplete dominance flower which produces pink flowers B: Complete dominance A: Artificial selection 1.3.4 Environment is the selective force B: Natural Selection (4x2) (8) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 8 (Second Paper) 10832/16 1.4 Paternity testing involves TWO procedures used to determine the biological father of a child. Procedure 1: ABO blood groups Procedure 2: DNA profiling The following data shows the results of two different procedures attempting to identify the biological father of a child. The mother of the child is confirmed. Procedure 1: ABO blood Groups Mother Child Male 1 Male 2 Male 3 A O O A B Procedure 2: DNA profiling data Mother Child Male 1 Male 2 Male 3 1.4.1 From the ABO blood group data, identify which male(s) could be the biological father of the child. (1) 1.4.2 From the DNA profile, identify which male could be the biological father of the child. (1) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 9 (Second Paper) 10832/16 1.4.3 Give the genotype of the blood group: (a) Of the child (1) (b) Of the mother (1) 1.4.4 Choose TWO ways from the list below (other than for paternity testing) in which DNA profiling is used. Write the numbers only. (i) Test for specific alleles that can cause a genetic disorder (ii) Growing tissues for organ transplants (iii) Data research in population distribution (iv) Identifying criminals (2) (6) 1.5 The diagram shows a part of an mRNA molecule attached to an organelle in the cytoplasm. The short length of mRNA sequence is shown below: AUG GCC UCG AUC ACG GCC AUC AUG 1.5.1 Where in the cell is mRNA formed? (1) 1.5.2 State the maximum number of amino acids in this polypeptide for which this piece of mRNA above could code. (1) 1.5.3 Give the DNA nitrogenous base triplet for the mRNA codon UCG. (1) 1.5.4 Which stage of protein synthesis is represented in the diagram? (1) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 10 (Second Paper) 10832/16 1.5.5 Name: (a) Organelle X (1) (b) Molecule Y (1) 1.5.6 Determine how many different types of Molecule Y would be used to produce a polypeptide from this piece of mRNA shown in the diagram. (1) 1.5.7 If the mRNA codon is AUC. Give the anticodon sequence in Molecule Y which would bind to the mRNA at this site. (1) (8) TOTAL SECTION A: 50 P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 11 (Second Paper) 10832/16 SECTION B QUESTION 2 2.1 Haemoglobin is made up of two types of polypeptide chains. In people with sickle cell anaemia, one polypeptide chain has one amino acid which is different from the normal sequence. This is due to a mutation which produces the base sequence CAT instead of CTT in the DNA molecule. The table below shows the mRNA codons for some amino acids. mRNA base Amino acid codon CAU histidine CAA glutamine GUA valine GAA glutamic acid CUU leucine GAU aspartic acid 2.1.1 State what is meant by a mutation. (1) 2.1.2 Is the mutation mentioned above an example of a gene mutation or a chromosomal aberration? (1) 2.1.3 Explain your answer to Question 2.1.2. (2) 2.1.4 Use ALL the information above and the table to determine the: (a) Amino acid present in normal haemoglobin (1) (b) Amino acid present in sickle cell haemoglobin (1) (6) 2.2 Describe the process of how a polypeptide is formed in the ribosome during protein synthesis. (6) (6) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 12 (Second Paper) 10832/16 2.3 In two separate experiments, blood group frequency in humans and egg size in chickens were investigated. The following data was collected and the results graphed. Graph A Graph B Blood group numbers in a population Blood Group Frequency Egg Size Frequency Number of chickens Blood Type Egg weight (g) 2.3.1 Identify which graph represents: (a) Continuous variation (1) (b) Discontinuous variation (1) 2.3.2 Describe the differences between the graphs, supporting your answer with a description of continuous and discontinuous variation. (4) (6) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 13 (Second Paper) 10832/16 2.4 An investigation was set up to study the effect of an antibiotic on three strains of bacteria (A, B and C). Agar plates were set up as shown below. Agar plate 1 Agar plate 2 Agar plate 3 KEY Disc of the same antibiotic x placed on Surface Surface Surface each plate Method covered with covered with covered with bacterium A bacterium B bacterium C Clear zone no bacteria Bacterial growth Incubation at 37oC for 48 hours Result [Adapted from 2004 HSC NSW: Section I - Part B Q27] The plates were incubated at 37oC for 48 hours. The diagram of plates 1, 2 and 3 in the bottom row show the results of the investigation. 2.4.1 Formulate a hypothesis for this investigation. (2) 2.4.2 State the dependent variable in this investigation. (1) 2.4.3 Write a conclusion to the experiment. (2) 2.4.4 State TWO other factors, not stated in the question, that must be kept constant in the investigation. (2) 2.4.5 Identify ONE safe work practice used to minimise risks associated with handling or identifying bacteria. (1) 2.4.6 Suggest ONE way in which the reliability of the results can be improved. (1) 2.4.7 The widespread use of antibiotics for the treatment of bacterial infections has led to the development of antibiotic resistance in some species of bacteria. From your knowledge of evolution explain how resistance has developed in bacteria. (5) (14) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 14 (Second Paper) 10832/16 2.5 Cloning is a technique that could be used to increase numbers of an endangered species. 2.5.1 Explain the effect that cloning could have on the genetic diversity of a species. (2) 2.5.2 Describe TWO ways in which cloning in animals or plants can be beneficial to humans. (2) (4) 2.6 Describe TWO ways in which punctuated equilibrium differs from Darwin’s Theory of natural selection. (4) [40] P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 15 (Second Paper) 10832/16 QUESTION 3 3.1 Colour-blindness is a sex-linked inherited condition which affects the photoreceptors of the eye. It is caused by a recessive allele. The diagram shows the inheritance of colour-blindness in one family. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 KEY: = Colour-blind male = Normal vision male = Colour-blind female = Normal vision female 3.1.1 Give evidence from the diagram which suggests that colour-blindness is: (a) Sex-linked (1) (b) Caused by a recessive allele (1) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 16 (Second Paper) 10832/16 3.1.2 Use the following symbols. XD = an X chromosome carrying the normal allele Xd = an X chromosome carrying the allele for colour-blindness Identify all the possible genotypes for the following persons: (a) 5 (b) 7 (c) 8 (4) 3.1.3 Assume that Person 14 is a carrier of the colour-blindness allele. She has recently married Person 15. Represent a genetic cross to determine the probability of their first child being born colour-blind. (6) (12) 3.2 Indian maize has four grain types that involve combinations of colour and appearance. Four alleles are involved, which are located on two pairs of homologous chromosomes (each gene on a separate chromosome). The alleles are: B = black b= yellow R = round r = wrinkled The table below shows the results of a cross between two hybrid Indian maize plants. Grain phenotype Observed number of offspring Black and round 144 Black and wrinkled 48 Yellow and round 48 Yellow and wrinkled 16 TOTAL 256 3.2.1 State the type of genetic cross represented in the above table. (1) 3.2.2 State the phenotype of the parents. (2) 3.2.3 Determine the genotypes of the yellow and round offspring. (2) 3.2.4 Predict the possible gametes produced by the parents. (2) 3.2.5 Using the data, calculate the phenotype ratio in this cross. (2) (9) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 17 (Second Paper) 10832/16 3.3 Biologists believe that human beings, gorillas and chimpanzees share a common ancestor. They do not agree as to how this common ancestor evolved into these three species. The diagram shows three models to represent the evolutionary relationship between the three species and the ancestor. Model 1 Model 2 Model 3 Human beings and Human beings and Chimpanzees and gorillas closely related chimpanzees closely related gorillas closely related Human beings Human beings Human beings Ancestor Gorillas Chimpanzees Chimpanzees Ancestor Ancestor Chimpanzees Gorillas Gorillas [Adapted from AQA-AHSH.20-QP-NOV07] The table below summarises some of the available evidence concerning the relationship among the three species. Characteristic Gorillas Humans Chimpanzee Model indicated Legs shorter Arms shorter Legs shorter Limb length 3 than arms than legs than arms Thumbs Short Long Short A Molecules Slight Not Human Identical B difference applicable haemoglobin 3.3.1 State the relevant evolutionary relationship for: (a) A (1) (b) B (1) P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 18 (Second Paper) 10832/16 3.3.2 Tabulate the anatomical differences of the cranial ridge and spine between African Apes and humans. (4) 3.3.3 Much of the evidence for the evolution of humans comes from studying fossils. State TWO ways why fossil evidence is often difficult to interpret. (2) 3.3.4 (a) Define the term transitional species. (2) (b) Explain why Australopthecines are regarded as a transitional species between Ardipithecus and Homo species with regard to the position of the foramen magnum. (3) (13) 3.4. Use the information in the diagram below to explain the formation of a new species of frog. Mud bank Flooding causes a mud slide Mud bank Gene Flow Population and Species Population Population Species X Species Y A B Diagram 1 Diagram 2 Diagram 3 (6) [40] TOTAL SECTION B: 80 P.T.O.

Downloaded from hlayiso.com LIFE SCIENCES 19 (Second Paper) 10832/16 SECTION C QUESTION 4 Describe how meiosis, mutations, chance fertilisation and random mating contribute to variation among individuals of the same species. Content: (17) Synthesis: (3) (20) NOTE: NO marks will be allocated for answers in the form of flow charts, diagrams or tables. TOTAL SECTION C: 20 TOTAL: 150 END