2016 RVHS H2 Biology Prelims Paper 3 Questions

River Valley High School Pg 1 of 16 Year 6 H2 Biology 9648 Paper 3 2016 Preliminary Examination II RIVER VALLEY HIGH SCHOOL YEAR 6 PRELIMINARY EXAMINATION II CANDIDATE NAME CENTRE NUMBER S INDEX NUMBER H2 BIOLOGY 9648/03 Paper 3 Application Paper 20 Sep 2016 2 hours Additional Materials: Answer Paper READ THESE INSTRUCTIONS FIRST Write your index number and name on all the work you hand in. Write in dark blue or black pen. You may use a HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Section A Answer all questions in the spaces provided on the question paper. Section B Answer all question on the answer paper provided. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. At the end of the examination, fasten all your work securely together. The number of marks is gi ven in brackets [ ] at the end of each question or part question. For Examiner’s Use Section A 1 / 13 2 / 13 3 / 14 4 / 12 Section B 5 / 20 Total / 72 _____________________________________________________________________ This Question Paper consists of 16 printed pages.

River Valley High School Pg 2 of 16 Year 6 H2 Biology 9648 Paper 3 2016 Preliminary Examination II Section A (80 marks) Answer all the questions in this section. 1 The coat colour of Norwegian cattle is mainly determined by the distribution of two pigments: red and black. Both pigments ar e produced by the action of the enzyme tyrosinase, in cells called melanocytes. A low level of activity of the enzyme leads to the production of red pigment, while a high activity of the enzyme produces black pigment. The activity of the enzyme is increased by the melanocyte stimulating hormone (MSH), which binds to the MSH receptor. The receptor is encoded by gene E, which has three alleles, E D, EA and e. ED and EA each encodes a receptor with different activity. No receptor is produced by the recessive allele, e. Alleles ED and EA differs by a single base substitution; while alleles e and EA differs by a single base deletion. (a) Explain how a mutation at EA allele may result in the protein encorded by e allele. [3] DNA was extracted from the frozen semen of six bulls with different genotypes at the E locus. The DNA from each animal was separately digested with two different restriction enzymes, P and Q. The products of each digestion were separated on a gel and the banding pattern shown in Fig. 1.1. Fig. 1.1

River Valley High School Pg 3 of 16 Year 6 H2 Biology 9648 Paper 3 2016 Preliminary Examination II (b) (i) Explain why the banding patterns from the same genotype are different when a different restriction enzyme is used. [2] (ii) Explain the role of marker DNA. [2] (iii) State which genotype(s) can be identified by using each of the two restriction enzymes. [2] P: Q:

River Valley High School Pg 4 of 16 Year 6 H2 Biology 9648 Paper 3 2016 Preliminary Examination II Bovine somatotropin (BST) is an animal hormone used to increase milk production in dairy cows. BST is naturally produced in the cow pituitary gland in small quantity and is used to regulate metabolic processes. With the advent of biotechnology, BST gene can be cloned in Escherichia coli. The bacteria are grown in bioreactors to produce BST, which is purified to produce hormone for injection. Fig. 1.2 shows the plasmid map of the BGH1 plasmid, used for transformation of BST gene into E.coli. Sal 1 restriction enzyme was used to cut the BGH1 plasmid for insertion of BST gene. Fig. 1.2 (c) (i) Describe the natural role of Sal 1 restriction enzyme. [2] (ii) Explain how AmpR gene facilitates BST gene cloning. [2] [Total: 13]

River Valley High School Pg 5 of 16 Year 6 H2 Biology 9648 Paper 3 2016 Preliminary Examination II 2 Omega-3 fatty acids are polyunsaturated fats that are often marketed as health supplements to prevent cholesterol deposits in arterial walls. In the wild, omega-3 fatty acids are produced by marine algae and accumulate in small fishes that feed on them. These small fishes are then fed to farmed fishes to increase their omega-3 fatty acid content. Farmed fishes high in omega-3 fatty acids serve as a good source for omega-3 fatty acid extraction for the health supplement industry. A new method to produce omega-3 fatty acids involves insertion of seven genes of the marine algae into oilseed plant, Camelina sativa. The resulting seed pods contain as much as 200 milligrams of omega-3 fatty acids in a single tablespoon of ‘fish oil’ extracted. Currently, this ‘fish oil’ is fed to farmed fishes, in replacement of small fishes. The effect of human consumption of ‘fish oil’ from genetically modified C. sativa seed pods is still under investigation. Fig. 2.1 Source: http://www.independent.co.uk/news/science/new-gm-cereal-crop-produces-fish-oil-in-its-seeds- 10372772.html (a) A Ti plasmid containing the seven genes from marine algae is constructed and introduced into A. tumefaciens before infecting C. sativa plant cells. Describe the properties of Ti plasmids that make them suitable as vectors in this process. [2]

River Valley High School Pg 6 of 16 Year 6 H2 Biology 9648 Paper 3 2016 Preliminary Examination II (b) Suggest why crop plants like C. sativa are better candidates for genetic modification than fishes. [2] (c) (i) With reference to Fig 2.1 , suggest two benefits of using genetically modified C. sativa as an omega-3 fatty acid source for farmed fishes. [2] (ii) Describe an ethical and a social implication associated with genetically modified C. sativa ‘fish oil’. [2]

River Valley High School Pg 7 of 16 Year 6 H2 Biology 9648 Paper 3 2016 Preliminary Examination II The effectiveness of genetically modified C. sativa seed pods in preventing cholesterol deposition in arteries was investigated using rodents, to evaluate if they can be used to substitute fish oil from farmed fishes. Effectiv eness is evaluated by analysing the levels of total omega-3 fatty acids available in blood and the diameter of rodents’ arteries. Rodents were divided into three groups of 10 and were subjected to respective treatment for a period of six months as shown below. Group A: High fat diet enriched with ‘fish oil’ from genetically modified C. sativa seed pods Group B: High fat diet enriched with fish oil from farmed fishes fed with small fishes Control: High fat diet without fish oil The results are summarised in the Table 2.1. Table 2.1 Group A Group B Control Total omega-3 fatty acids level/ mmolL-1 33.7 ± 0.3 27.1 ± 0.1 20.0 ± 0.3 Cross section of artery after 6 months x (d) With reference to Table 2.1 , comment on whether genetically modified C. sativa is a more effective substitute. [3]

River Valley High School Pg 8 of 16 Year 6 H2 Biology 9648 Paper 3 2016 Preliminary Examination II (e) Describe how genetic engineering is used to increase quality of another named crop plant. [2] [Total: 13]

River Valley High School Pg 9 of 16 Year 6 H2 Biology 9648 Paper 3 2016 Preliminary Examination II 3 Severe combined immunodeficiency disease (SCID) is caused by a severe genetic defect often found in newborns. The condition must be diagnosed and treated quickly to prevent serious complications. However, doctors continue to struggle with often ineffective treatment options. In recent studies, researchers found that blood stem cells may effectively treat SCID caused by a deficiency in the adenosine