Life Sciences P2 1 FS/September 2016 Grade 12 Prep. Exam. PREPARATORY EXAMINATION GRADE 12 LIFE SCIENCES P2 SEPTEMBER 2016 MARKS: 150 TIME: 2½ HOURS

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1 Life Sciences P2 1 FS/September 2016 PREPRTORY EXMINTION GRE 12 LIFE SIENES P2 SEPTEMER 2016 MRKS: 150 TIME: 2½ HOURS This question paper consists of 17 pages.

2 Life Sciences P2 2 FS/September 2016 INSTRUTIONS N INFORMTION Read the following instructions carefully before answering the questions nswer LL the questions. Write LL the answers in the NSWER OOK. Start the answers to EH question at the top of a NEW page. Number the answers correctly according to the numbering system used in this question paper. Present your answers according to the instructions of each question. LL drawings must be done in pencil and labelled in blue or black ink. raw diagrams, tables or flow charts only when asked to do so. The diagrams in this question paper are NOT necessarily drawn to scale. o NOT use graph paper. You must use a non-programmable calculator, protractor and compass, where necessary. Write neatly and legibly.

3 Life Sciences P2 3 FS/September 2016 SETION QUESTION Various options are provided as possible answers to the following questions. hoose the correct answer and write only the letter ( to ) next to the question number (1.1.1 to 1.10) in the NSWER OOK, for example Two individuals are most likely members of the same species if they have a different number of chromosomes. can mate and produce fertile offspring. breed at different times during the year. are phenotypically different Which ONE of the following is most likely the chromosome complement of a person with own syndrome? 46 + XX 46 + XY 45 + XX 44 + XY Which of the following correctly identifies the relationship between alleles, chromosomes, and genes? Genes contain chromosomes and alleles hromosomes contain genes but not alleles lleles are found in chromosomes but not in genes lleles are different forms of genes found in chromosomes uring meiosis II in humans... homologous pairs of chromosomes separate. chromosomes arrange singly at the equator. only the sex chromosomes separate. N replication takes place RN differs from N in that RN... has deoxyribose sugar and uracil. has thymine and a phosphate group. has uracil and a ribose sugar. is a double-stranded molecule.

4 Life Sciences P2 4 FS/September If the mother has blood group and the father blood group O the possible blood groups of the offspring will be... or only. only. O only.,, or O Which of the following shows the process of N replication in the correct sequence? N helix unwinds strand unzips complementary bases pair two identical N strands form. Two N helixes unwind strand unzips complementary bases pair one N strand form. N helix unzip strands unwinds complementary bases pair one N strand form. N helix unwinds strand unzips complementary bases pair one N strand form In humans the ability of the tongue to roll is a dominant trait. The inability to roll the tongue is recessive. If two individuals who are homozygous recessive for this trait have a child, the chance that the child will be able to roll his/her tongue, is 75%. 100%. 0%. 50% Which ONE of the following monohybrid crosses of complete dominance will result in a phenotypic ratio of 3:1? cross where both parents are heterozygous. one parent is heterozygous and the other is homozygous recessive. both parent are homozygous for the dominant characteristic. one parent is heterozygous and the other is homozygous dominant The molecules that are involved in transcription are... mrn and amino acids. N and trn. N and mrn. trn and mrn. (10 x 2) (20)

5 Life Sciences P2 5 FS/September 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 the NSWER OOK n allele that influences the phenotype whether in the homozygous or heterozygous combination onds by which the base pairs are linked in N Point of overlap of chromatids during crossing over Opening in the skull through which spinal cord enters Group of organisms of the same species occupying the same habitat Tangled network of chromosomes located in the nucleus Openings in the nuclear membrane that allow mrn to leave the nucleus The type of nucleic acid on which the anti-codon for protein synthesis is located (8) 1.3 Indicate whether each of the descriptions in OLUMN I applies to ONLY, ONLY, OTH N or NONE of the items in OLUMN II. Write only, only, both and, or none next to the question number (1.3.1 to 1.3.3) in the NSWER OOK. OLUMN I Produced the first X-ray pictures of N ll the genes in all the chromosomes of a species The chromosome number of a cell formed by meiosis : : : : : : OLUMN II Watson Franklin Genome Genotype iploid Haploid (3 x 2) (6)

6 Years ago Life Sciences P2 6 FS/September The following represents a possible phylogenetic tree of ustralopithecus and Homo species. 0 ppearance of art Homo sapiens First burials Homo neanderthalensis Homo erectus Moved out of frica ontrol of fire Homo habilis Use of tools ustralopithecus africanus ustralopithecus afarensis rdipithecus ramidus ipedal hominids [dapted from: m.ivyroses.com/human evolution] How many years ago did Homo neanderthalensis disappear from earth? ccording to the phylogenetic tree: (a) (b) (c) Which was the first group to use tools? Which TWO ustralopithecus species co-existed? Which species moved out of frica? Name ONE fossil of ustralopithecus found in South frica. (6)

7 Life Sciences P2 7 FS/September Three ladies each gave birth to a baby boy in a large hospital. The babies were accidentally swopped. The most accurate way to correctly match each baby with his parents was by using N profiles. The N profiles are shown below. SMITH STEVENS JONES Y MR MRS MR MRS MR MRS Which baby (1, 2 or 3) belongs to the: (a) (b) Smith's? Jones'? State THREE other uses for N profiling. (3) (5)

8 Life Sciences P2 8 FS/September The diagram below shows two phases of meiosis. iagram I iagram II Provide labels for and. Identify the phase represented by diagram I. State the functions of and. TOTL SETION : (5) 50

9 Life Sciences P2 9 FS/September 2016 SETION QUESTION The diagram below shows one stage of protein synthesis. X Y mrn U U U G U G U U G G amino acid Name: (a) (b) (c) organelle X structure Y the stage of protein synthesis shown in the diagram Name and describe the process that occurs in the nucleus to produce mrn. The table below shows the mrn codons that code for different amino acids. Using the information in the table and the diagram above, write down the sequence of the amino acids that are represented by numbers 2 and 4. (5) OON OF mrn UU GU GG G MINO I Proline Leucine Glycine Glutamic acid Valine Give the base sequence on N that codes for the amino acid leucine. (11)

10 Life Sciences P2 10 FS/September In humans eyebrows are either connected or not connected to each other. Eye brows not connected Eye brows connected Study the family tree shown below that shows the inheritance of connected and not connected eyebrows over four generations. Key: E F Male with eyebrows not connected Male with eyebrows connected Female with eyebrows not connected Female with eyebrow connected Pedigree diagram showing inheritance of connected or not connected eyebrows. Which type of eyebrows is controlled by the dominant allele? Give a reason for your answer to QUESTION using evidence from the pedigree above. Persons E and F are twins. id they develop from a single fertilised egg or from two fertilised eggs? Give TWO reasons based on their phenotypes to support your answer to QUESTION What percentage of females in the pedigree diagram's eyebrows are connected? (8)

11 Life Sciences P2 11 FS/September In humans brown tooth enamel is inherited as a sex-linked recessive trait. man who carries the recessive allele will have brown tooth enamel. man with brown tooth enamel marries a woman with white teeth, but whose father had brown tooth enamel. Use X for white teeth enamel and X b for brown tooth enamel Explain why the woman is heterozygous for tooth enamel colour. Use a genetic cross to show the possible ratio of the phenotypes of their children. (4) (6) (10) 2.4 Read the extract and answer the questions that follow. Mysterious N The genome is made up of all N in a human. The human genome has genes and the average gene has about bases. The genes make up only 2% of the human genome and the rest of the N consists of non-coding regions. Some of them are used for regulating chromosomal structure and the quantity and quality of proteins made. The function of 50% of the N, made up of repeated sequences and known as 'junk N', is not yet known. Some scientists differ from the above view. ccording to r arolyn Hancock, genes make up 5% of the human genome. [dapted from: Name TWO functions of non-coding N. ccording to r arolyn Hancock, what percentage of N is called 'junk N'? List characteristics shared by N and RN. (3) (6)

12 Life Sciences P2 12 FS/September In rats the allele for a black coat colour () is dominant over the allele for a white coat colour (b). The allele for a long hair (L) is dominant over the allele for a short hair (l) Two rats were crossed. The genotypes of their offspring are represented in the Punnett diagram below, except at (i) and (ii). L l bl bl l Ll ll bll (i) bl bll bll (ii) bbll Give the: (a) (b) Genotype of the offspring at (i) Phenotype of the offspring at (ii) If rats produce offspring all with the genotype bll and the female genotype is bbll, state the only possible genotype of the male. (5) [40]

13 Life Sciences P2 13 FS/September 2016 QUESTION The diagrams below show the skeletons of two hominids. Organism 1 Organism State TWO advantages of bipedalism. Identify TWO similarities in the forelimbs of organism 1 and organism 2. Explain the significance of the change of the pelvis towards bipedalism. State TWO advantages of the larger cranial capacity of organism 2. (4) (10)

14 Life Sciences P2 14 FS/September Earth originally existed as one large land mass that later drifted apart and formed the continents as we know it today. The following two pictures are those of baobab trees found on the continent of frica (iagram I) and found on the continent of ustralia (iagram II). IGRM I IGRM II Explain how the two species of baobab trees shown above might have formed. (6)

15 Life Sciences P2 15 FS/September n investigation was done by grade 12 learners to compare the speed of left-handed persons and right-handed persons in mirror writing. Mirror writing is writing in the opposite direction to what is considered normal writing. This is the writing seen in front of ambulances so that drivers in front of the ambulance can read the text in their rear-view mirrors. The following steps were carried out: Twenty learners were selected, ten left-handed and ten righthanded. simple text sentence was given to them to change into mirror writing. stopwatch was used to measure the time taken for each learner to finish the task. The recording of their task was done in seconds. The results of the investigation are shown in the table below. TIME TKEN TO PERFORM MIRROR WRITING IN SEONS LERNERS verage Time LEFT-HNERS RIGHT-HNERS Formulate a hypothesis for this investigation. State the independent variable in this investigation. Identify TWO variables which were kept constant in this investigation other than the one given in the investigation. What conclusion can be drawn from this investigation? raw a bar graph to show the average time taken for lefthanders and right-handers to write the sentence. (6) (13)

16 Life Sciences P2 16 FS/September In 1971, ten wall lizards (Podarcis sicula) were introduced to an island from a neighboring island. fter being left for some decades they where compared by scientists to the colony from which they were taken originally. The Island on which they were released had very few insects and more vegetation. They were found to have changed from an insectivorous diet to a vegetarian diet. This diet change seemed to have brought visible changes in the wall lizards. THE EVOLUTION OF THE WLL LIZR Original lizard Lizard after decades Head smaller for eating insects with less bite force Head larger with more bite force for chewing leaves ody larger Tail thicker [dapted from List THREE characteristics other than head size that changed in Podarcis sicula. (3) Explain how the change in diet can account for the larger body size Use your knowledge of natural selection to explain the changes in size of the head of the wall lizard. (6) (11) [40] TOTL SETION : 80

17 Life Sciences P2 17 FS/September 2016 SETION QUESTION 4 The characteristics of organisms can be changed through selective breeding and genetic engineering. Use an example to describe selective breeding and also describe the similarities and the differences between natural selection, selective breeding and genetic engineering. ontent: Synthesis: NOTE: NO marks will be awarded for answers in the form of flow charts or diagrams. (17) (3) (20) TOTL SETION : GRN TOTL: