Life Sciences P2 Feb March 2017 Eng hlayiso.com

Downloaded from hlayiso.com GRAAD 12 NATIONAL SENIOR CERTIFICATE GRADE 12 LIFE SCIENCES P2 FEBRUARY/MARCH 2017 MARKS: 150 TIME: 2½ hours This question paper consists of 16 pages. Copy right reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 2 DBE/Feb.–Mar. 2017 NSC 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. Copy right reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 3 DBE/Feb.–Mar. 2017 NSC SECTION A QUESTION 1 1.1 Various options are provided as possible answers to the following questions. Write down the question number (1.1.1–1.1.8), choose the answer and make a cross (X) over the letter (A–D) of your choice in the ANSWER BOOK. EXAMPLE: 1.1.9 A B C D 1.1.1 The process where one DNA molecule produces two identical DNA molecules is called … A reproduction. B replication. C translation. D protein synthesis. 1.1.2 A difference between DNA and RNA: A RNA is double-stranded and DNA is single-stranded. B DNA has a sugar-phosphate frame, whereas RNA does not. C There are weak hydrogen bonds in DNA, but not in RNA. D RNA has a helix structure and DNA is straight. 1.1.3 A pedigree diagram shows … A how organisms evolve. B the inheritance of characteristics over many generations. C sex-linked characteristics only. D the number of children in a family only. 1.1.4 A red flowering plant is crossed with a white flowering plant. All the offspring have pink flowers. When the two pink flowering plants are crossed, the next generation of flowering plants will have flowers that are … A pink only. B red only. C white only. D pink, red and white. Copy right reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 4 DBE/Feb.–Mar. 2017 NSC 1.1.5 The diagram below represents the chemical structure of a protein. X Y Amino acids X represents a … A hydrogen bond. B nitrogen base. C peptide bond. D mRNA molecule. 1.1.6 The difference between nucleic acids and nucleotides is that ... A nucleic acids are building blocks of nucleotides. B nucleotides are building blocks of nucleic acids. C nucleotides are larger than nucleic acids. D nucleic acids are found in the nucleus and nucleotides are found in the cytoplasm. 1.1.7 Which ONE of the following events occurs during metaphase I of meiosis? A Homologous chromosomes arrange themselves at the equator B Centrioles move to opposite poles C Chromosomes arrange themselves singly at the equator D Splitting of the cytoplasm 1.1.8 Comparisons of the amino acid sequences in a protein have been made between humans and a number of other organisms. The number of differences is shown in the table below. ORGANISM SHARK KANGAROO FISH COW LIZARD Number of differences in amino acid 79 27 68 17 62 sequences in a protein compared to humans [Adapted from AQA Biology 1998] The type of evidence for evolution in the table above is … A fossil evidence. B biogeography. C cultural evidence. D genetic evidence. (8 x 2) (16) Copy right reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 5 DBE/Feb.–Mar. 2017 NSC 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 1.2.7) in the ANSWER BOOK. 1.2.1 A sudden change in the sequence/order of nitrogenous bases of a nucleic acid 1.2.2 Explanation of an observation that is supported by facts, models and laws 1.2.3 The breeding of organisms over many generations in order to achieve a desirable phenotype 1.2.4 The type of sugar found in an RNA molecule 1.2.5 Type of evolution involving long periods of time when species do not change and short periods of rapid change 1.2.6 The hypothesis which supports migration of human ancestors from the point of origin 1.2.7 The mineralised remains of organisms that have lived in the past (7 x 1) (7) 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 1.3.3) in the ANSWER BOOK. COLUMN I COLUMN II 1.3.1 Occurs during telophase of A: Dividing of the cytoplasm meiosis I B: Centrioles move to the opposite poles 1.3.2 Location of DNA A: Nucleus B: Mitochondria 1.3.3 Found in African apes and A: Claws instead of nails humans B: An opposable thumb (3 x 2) (6) Copy right reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 6 DBE/Feb.–Mar. 2017 NSC 1.4 The diagram below shows possible evolutionary relationships among primates. New World monkeys Old World monkeys Lorises Lemurs Tarsiers Apes Present 25 40 50 58 63 Million years ago (mya) [Source: http://dl0.creation.com/articles] 1.4.1 How many million years ago did the: (a) Apes appear on Earth (1) (b) Common ancestor evolve to form the Tarsiers and Lemurs (1) 1.4.2 Which TWO species share the most recent common ancestor? (2) 1.4.3 Which species is most closely related to the Lemur? (1) (5) Copy right reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 7 DBE/Feb.–Mar. 2017 NSC 1.5 The diagrams below represent a chromosome pair in a female human cell. The cells (A, B and C) show different events in a phase of meiosis, which are not necessarily in the correct sequence. Y X A B C 1.5.1 How many pairs of chromosomes occur in a normal human cell? (1) 1.5.2 Give labels for: (a) Structure X (1) (b) Area Y (1) 1.5.3 Name the organ in the human female where meiosis occurs. (1) 1.5.4 Name the: (a) Process occurring in diagram B (1) (b) Phase represented by the diagrams above (1) (c) Type of cells that would result from meiosis of this cell (1) 1.5.5 Arrange the letters A, B and C to show the correct sequence of the events. (1) (8) Copy right reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 8 DBE/Feb.–Mar. 2017 NSC 1.6 Coat colour in mice is controlled by two alleles, black (B) and grey (b). Tail length is controlled by two alleles, long (T) and short (t). The Punnett square below shows a part of the cross between two mice. Genotype (i) has been left out. Parent 1 Gametes BT Bt bT bt Bt BBTt BBtt BbTt Bbtt Parent 2 Bt BBTt BBtt BbTt Bbtt Bt BBTt BBtt (i) Bbtt Bt BBTt BBtt BbTt Bbtt 1.6.1 Give the: (a) Genotype of parent 1 (2) (b) Phenotype of parent 2 (2) (c) Genotype of offspring (i) (1) 1.6.2 What percentage of the offspring above is grey with short tails? (1) 1.6.3 State the genotypes of TWO gametes from the table above that will result in offspring that are heterozygous for both traits, if fertilisation occurs. (2) (8) TOTAL SECTION A: 50 Copy right reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 9 DBE/Feb.–Mar. 2017 NSC SECTION B QUESTION 2 2.1 Read the passage below. NEW HOMININ SPECIES DISCOVERED On 13 September 2013 scientists discovered fossils in the Sterkfontein Caves in South Africa which appeared to belong to a previously unknown species of hominins. The fossils were classified as a new species, Homo naledi. The physical characteristics of H. naledi are described as having traits similar to the genus Australopithecus, mixed with traits more characteristic of the genus Homo. It appeared that H. naledi represented a transitional fossil. An analysis of H. naledi's skeleton suggests that it stood upright and was bipedal. The structure of the pelvis is similar to the Australopithecines, but its legs, feet and ankles are more similar to the genus Homo. Four skulls were discovered, each with approximately half the volume of modern human skulls. The H. naledi skulls are closer in cranial volume to the skull of Australopithecus, but the cranium structure is more similar to those found in the genus Homo. The teeth are much smaller than those of Australopithecus and similar to the teeth of modern humans. [Adapted from https://humanorigins.si.edu/evidence] 2.1.1 Define the term transitional fossil. (2) 2.1.2 Name a characteristic from the passage that Homo naledi shared with both Australopithecus and Homo. (1) 2.1.3 State ONE other characteristic from the passage that Homo naledi shared only with Australopithecus. (1) 2.1.4 Explain TWO characteristics of a skeleton which are adaptations for bipedalism. (4) 2.1.5 Give ONE possible reason why there was a change to smaller teeth in modern humans. (3) (11) Copy right reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 10 DBE/Feb.–Mar. 2017 NSC 2.2 Study the table below that shows the change in antibiotic resistance in three strains of bacteria (MRSA, VRE and FQRP) over a period of 20 years. ANTIBIOTIC RESISTANCE (% ) YEAR MRSA VRE FQRP 1981 2 0 0 1985 10 0 0 1989 15 2 0 1993 40 5 5 1997 40 20 10 2001 60 20 25 [Source: http://wallace.genetics.uga.edu/groups/evol] 2.2.1 Which bacterial strain was the: (a) Most resistant to antibiotics over the years (1) (b) Last to develop antibiotic resistance (1) 2.2.2 Calculate the percentage increase in antibiotic resistance in VRE from 1993 to 1997. (3) 2.2.3 Draw a line graph to show the development of antibiotic resistance in the bacterial strain MRSA. (6) (11) Copy right reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 11 DBE/Feb.–Mar. 2017 NSC 2.3 The diagram below represents nitrogen-base sequences of a part of a nucleic acid that codes for making insulin. Insulin is necessary for the uptake of sugar from the blood. The sequences below are from two individuals and are read from left to right. Sequence 1 is from a normal person and sequence 2 is from a person who shows a mutation and cannot produce insulin. TWO NITROGEN-BASE SEQUENCES OF A PART OF A NUCLEIC ACID Sequence 1 TAG CCA CAC GTT ACA ACG TGA AGG TAA Sequence 2 TAT CCA CAC GTT ACA ACG TGA AGG TAA [Source: www.biologyjunction.com] 2.3.1 Which nucleic acid is represented in both sequences? (1) 2.3.2 Where did the mutation in the second sequence occur? (1) The table below shows the amino acids coded for by different DNA base triplets. AMINO ACID DNA BASE TRIPLET CCG Glycine CCT CCC CAT Valine CAC GTA Histidine GTG GGA Proline GGC TAA Isoleucine TAT 2.3.3 Give the: (a) Anticodon of the fourth base triplet on sequence 2 (2) (b) Amino acid coded for by the first base triplet in sequence 2 (2) (6) 2.4 Describe the process of transcription in protein synthesis. (4) Copy right reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 12 DBE/Feb.–Mar. 2017 NSC 2.5 Tay-Sachs disease is caused by an autosomal recessive allele (n). Children with Tay-Sachs disease lose motor skills and mental functions. Over time, the children become blind, deaf, mentally retarded and paralysed. Tay-Sachs children die by the age of five. The pedigree diagram below shows the inheritance of Tay-Sachs disease in a family. Bill Pam Charly Helen Portia Patrick Elizabeth Sam [Source: www.tay-sachs.org] 2.5.1 Give: (a) Charly's phenotype (2) (b) Portia's genotype (2) (c) Bill's genotype (2) 2.5.2 Explain why Patrick is normal, but a carrier of Tay-Sachs disease. (2) (8) [40] Copy right reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 13 DBE/Feb.–Mar. 2017 NSC QUESTION 3 3.1 Tom and Maria have three children. One of the three children was adopted. A DNA profile for each member of the family was prepared to determine if Tom is the father of all three children (Anne, Mary and Steve). The DNA profiles are given below. Tom Maria Anne Mary Steve 3.1.1 Which ONE of the children has been adopted? (2) 3.1.2 Explain your answer to QUESTION 3.1.1. (2) (4) 3.2 Human blood groups are controlled by multiple alleles. 3.2.1 How many alleles control blood groups? (1) 3.2.2 Which TWO alleles are codominant in the inheritance of blood groups? (2) 3.2.3 A man is heterozygous for blood group A and marries a woman who has blood group O. Use a genetic cross to show the phenotypic ratio of their offspring. (7) (10) 3.3 Haemophilia is a genetic disorder caused by a recessive allele on the X chromosome. A haemophiliac female marries a normal male. Explain why all their sons will be haemophiliacs. (4) Copy right reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 14 DBE/Feb.–Mar. 2017 NSC 3.4 Finches of the species Geospiza fortis are found on one of the Galápagos Islands. There was variation in the size of their beaks. All the finches used to feed on small, soft seeds which were plentiful on the island. Then the island was affected by a severe drought which made food scarce. Many of the plants on the island died. The small, soft seeds were all gone. Only hard, woody seeds remained. Scientists conducted an investigation to determine the relationship between beak size and survival of the finches before and during the drought. The table below shows the results of part of the investigation. TOTAL NUMBER OF TOTAL NUMBER OF BEAK SIZE FINCHES BEFORE THE FINCHES DURING THE (mm) DROUGHT DROUGHT 7,3 2 0 7,8 12 2 8,3 30 4 8,8 48 4 9,3 45 6 9,8 40 8 10,3 25 10 [Adapted from Excerpt Evolution, Roberts et al.] 3.4.1 List FOUR steps that the scientists followed to obtain their results. (4) 3.4.2 Name the independent variable of this investigation. (1) 3.4.3 Describe the relationship between the number of finches during the drought and beak size. (2) 3.4.4 Give a possible reason for the relationship in your answer to QUESTION 3.4.3. (3) 3.4.5 Predict which beak size(s) would be present in the population if the drought continued. (1) (11) Copy right reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 15 DBE/Feb.–Mar. 2017 NSC 3.5 The diagram below shows a genetic engineering process. A donor cell was taken from the muscle cell of a male champion horse (stallion) to create a new offspring. Cell from muscle tissue of a male champion horse (stallion) Nucleus removed from muscle cell Nucleus placed in ovum of mare. An A electrical shock Ovum without results in the nucleus 'ovum' starting to Ovum from female horse divide. (mare) Nucleus of ovum is C B removed and discarded 'Ovum' divides normally D Offspring Embryo develops normally Embryo placed in uterus of adult female horse [Adapted from www.biologyreference.com] 3.5.1 Name the: (a) Genetic engineering process shown in the diagram above (1) (b) Process that produced ovum B (1) 3.5.2 Why is the donor cell extracted from a champion horse? (2) 3.5.3 Explain why only the nucleus of the donor cell is used. (2) 3.5.4 A somatic cell in a horse contains 64 chromosomes. How many chromosomes would there be in: (a) Structure A (1) (b) Ovum B (1) (c) A muscle cell in organism D (1) 3.5.5 Explain why the 'ovum' labelled C cannot be considered a gamete. (2) (11) [40] TOTAL SECTION B: 80 Copy right reserved Please turn over

Downloaded from hlayiso.com Life Sciences/P2 16 DBE/Feb.–Mar. 2017 NSC SECTION C QUESTION 4 The anole lizard of the Caribbean Islands represents a group of about 150 closely related species, which evolved within the past 50 million years from a single species. Use this example to describe how natural selection led to the process of speciation that gave rise to the 150 different species of lizards. Content: (17) Synthesis: (3) (20) NOTE: NO marks will be awarded for answers in the form of a table, flow charts or diagrams. TOTAL SECTION C: 20 GRAND TOTAL: 150 Copyright reserved