SENIOR CERTIFICATE EXAMINATION

Transcription

1 SENIOR ERTIFITE EXMINTION LIFE SIENES P MRKS: 150 TIME: 2½ hours This question paper consists of 14 pages.

2 Life Sciences/P2 2 E/2015 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, flow charts or tables 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 a compass where necessary. Write neatly and legibly.

3 Life Sciences/P2 3 E/2015 SETION QUESTION Various options are given as possible answers to the following questions. hoose the answer and write only the letter ( to ) next to the question number (1.1.1 to 1.1.8) in the NSWER OOK, for example Humans have 46 chromosomes in each somatic cell. Each gamete produced will have 22 autosomes and 1 gonosome. 21 autosomes and 2 gonosomes. 23 autosomes. 23 gonosomes 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 OLOUR NUMER OF FLIES Red 182 White 61 The genotypes of the parents were RR x Rr. Rr x rr. Rr x Rr. RR x rr Which ONE of the following is TRUE about genes? Genes are codes for a particular characteristic. made up of amino acids. made up of RN. found in a ribosome Which ONE of the following is used to produce genetically identical individuals? Stem cell research Genetic modification loning N profiling

4 Life Sciences/P2 4 E/2015 QUESTIONS and 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. O O 1 O 2 KEY Female Male PEIGREE IGRM Which ONE of the following represents the genotype and phenotype of individual number 1 above? ii and blood group O I i and blood group I i and blood group O I i and blood group If individual 2 has a child with blood group, then her partner could only have blood group.. O..

5 Life Sciences/P2 5 E/ Which ONE of the following is ORRET with regard to the structure of N and RN? RN is double-stranded and N is single-stranded. RN contains uracil and N contains thymine. RN is a very long molecule while N is a short molecule. RN forms a double helix while N does not Which ONE of the following represents molecules that make up a single nucleotide? Phosphate, sugar and a nitrogenous base Sugar, protein and phosphate Nitrogenous base, phospholipid and sugar denine, 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 NSWER OOK The type of inheritance involving two alleles of a gene that are not dominant over one other haracteristics controlled by genes which are located on the sex chromosomes hromosomes that are similar in structure and code for the same characteristics The monomers/building blocks of proteins The type of inheritance involving alleles that equally determine the phenotype of heterozygous offspring Undifferentiated cells which are able to develop into any other types of cells Intermediate fossils showing features of both more primitive and more advanced organisms n allele that is expressed phenotypically only in the homozygous condition genetic cross involving one characteristic only (9)

6 Life Sciences/P2 6 E/ Indicate whether each of the statements 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 1.3.4) in the NSWER OOK. OLUMN I iscovered the fossil of : ustralopithecus sediba : Example of continuous variation : : Pronounced brow ridges : : iscovered the structure of : N : OLUMN II Raymond art Ron lark Height lood groups frican apes Homo sapiens Watson rick (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, which is heterozygous for red fruit and homozygous tall, was crossed with Plant, which has yellow fruit and is short Write down the genotype of: Plant Plant Write down LL the possible genotypes of the gametes of plant. Name the phenotype of an offspring having the genotype: Rrtt RrTt Plant was then crossed with another plant (Plant ) and all the offspring had red fruit and were tall. Use this information to write down the genotype of Plant. (8)

7 Life Sciences/P2 7 E/ The diagram below shows cells of an organism in one of the phases of meiosis. E PHSE OF MEIOSIS Which phase of meiosis is represented in the diagram? Give the LETTER and NME of the part that: (c) Is responsible for the formation of the spindle fibres arries the genetic information Holds the chromatids together State the number of chromosomes that would be present in each of the cells of this organism: t the beginning of meiosis In a gamete of this organism (9) TOTL SETION : 50

8 Life Sciences/P2 8 E/2015 SETION QUESTION iagram 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. iagram 2 shows the same lake many years later. 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, and, for a long period of time. iagram 1 Rocky island iagram 2 Lake Lake FISH POPULTION IN LKE efine population. State FOUR possible causes of the variation in the fish population in iagram 1. Eventually, as shown in iagram 2, lake and lake contained two different species of fish. (4) Name the process that resulted in the fish population becoming two different species. Explain how the new species was formed. (6) (13) 2.2 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)

9 Life Sciences/P2 9 E/ The diagram below shows the process of protein synthesis. Y Process W X Z Process PROTEIN SYNTHESIS Identify the following molecules: W Y Name the part of protein synthesis indicated by process. escribe how a mutation on molecule W will affect the structure of the protein formed by process. (4) The following sequence represents a part of the nitrogenous base sequence on molecule X. G UG GG triplet 1 triplet 2 triplet 3 Write down the base sequence of the anticodon of triplet 1 shown above. The table below shows the amino acids that correspond with different N codes. MINO I rginine Glycine Methionine N OE TT T T Write down the correct sequence of amino acids for triplets 1 to 3. (3) (11)

10 Life Sciences/P2 10 E/ The graph below represents the results of an investigation which compares the conviction (number of people found guilty) of criminals with the use of N evidence and without the use of N evidence from 1989 to OMPRISON OF THE ONVITIONS WITH THE USE OF N EVIENE N WITHOUT THE USE OF N EVIENE, FROM 1989 TO Number of people found guilty (per arrests) Year onvictions with N evidence onvictions without N evidence Formulate a hypothesis for this investigation. State the dependent variable in this investigation. [dapted from How many more successful convictions per arrests were made in 2003 with the use of N evidence? Show LL calculations. N database is a collection of the N 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 N database. (4) (9) [40]

11 Life Sciences/P2 11 E/2015 QUESTION The photographs of two butterflies are provided below. oth butterflies live in the same habitat and are preyed on by predators. lthough these butterflies are very similar in appearance they are two separate biological species. mauris ochlea has an unpleasant taste while Hypolimnas deceptor does not have an unpleasant taste. mauris ochlea Hypolimnas deceptor TWO SPEIES OF UTTERFLY [From Explain why most predators are less likely to feed on Hypolimnas deceptor. Use arwin's theory of evolution through natural selection to explain the evolution of the Hypolimnas deceptor butterfly. State ONE way in which natural selection differs from artificial selection. (3) (6) (11)

12 Life Sciences/P2 12 E/ The diagram below shows possible relationships between members of the family Hominidae. POSSILE RELTIONSHIPS ETWEEN HOMINIS Present Time (million years ago) Homo sapiens Homo erectus Homo habilis ustralopithecus africanus ustralopithecus robustus ustralopithecus boisei ustralopithecus afarensis [dapted from What is the name given to the type of diagram above? How many of each of the following are represented in the diagram? Genera Species Explain why. robustus and. boisei are more closely related than. boisei and. afarensis. Which of the hominids in the diagram above is considered to have been the first to use tools? Name TWO ustralopithecus fossils found in South frica. Explain how the location and the age of Homo fossils are used as evidence for the 'Out of frica' hypothesis. (3) (11)

13 Life Sciences/P2 13 E/ The diagrams below represent parts of the skeletons of an frican ape and a human. iagrams and are drawn to scale. IGRM IGRM IGRM IGRM SKELETON PRTS OF FRIN PE N HUMN Write down the LETTERS only of the diagrams ( ) that represent bipedal organisms. Explain how the shape of the pelvis contributes to bipedalism. Explain the significance of the position of the foramen magnum in the skulls in diagram and in diagram. Tabulate THREE visible differences between the jaws/teeth of the skulls labelled and that indicate trends in human evolution. State THREE physical characteristics of the forelimb/upper limb that humans share with frican apes. TOTL SETION : (4) (7) (3) (18) [40] 80

14 Life Sciences/P2 14 E/2015 SETION QUESTION 4 escribe TWO types of mutations and how they lead to altered characteristics in FOUR genetic disorders you have studied. ontent: Synthesis: (17) (3) NOTE: NO marks will be awarded for answers in the form of tables, flow charts or diagrams. TOTL SETION : GRN TOTL: