19. Genetic technology
A section of Biology, 9700
Listing 10 of 107 questions
Factor VIII can be made as a recombinant human protein. Name the disease that is treated using recombinant human factor VIII. Before recombinant human factor VIII was available, this disease was treated with factor VIII from donated blood. Give two advantages of using recombinant human factor VIII, instead of factor VIII from donated blood, to treat this disease. The gene that codes for human factor VIII can be synthesised from messenger RNA purified from human liver cells. Name the enzyme that uses messenger RNA as a template to produce complementary DNA. Outline two sources, other than messenger RNA, from which genes can be obtained for genetic engineering. The gene that codes for human factor VIII can be transferred into mammalian cells in tissue culture. Explain why a promoter also needs to be transferred into the mammalian cells so that human factor VIII can be synthesised.
9700_m22_qp_42
THEORY
2022
Paper 4, Variant 2
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Interferon-alpha (IFN-α) can be produced as a recombinant human protein to treat some types of cancer. The gene IFNA2 codes for IFN-α. One method of producing recombinant IFN-α uses genetically engineered Escherichia coli bacteria that contain recombinant plasmids. Each recombinant plasmid contains: • the gene IFNA2 • three regulatory sequences of the lac operon (promoter, operator and lac• a gene for antibiotic resistance, AMPR. Each of the sequences for the lacI gene and AMPR gene contains its own promoter. As a result, these genes are always expressed in E. coli bacteria that contain this recombinant plasmid. is a diagram of the recombinant plasmid. The promoter regions of the lacI gene and AMPR gene are not shown. IFNA2 AMPR lacI o p e r a t o r p r o m o t e r The start of transcription of the gene IFNA2 by E. coli with the recombinant plasmid shown in needs to be controlled to obtain an optimum yield of IFN-α. Scientists investigated the effect of two inducers of transcription on the production of recombinant IFN-α: • lactose, which is converted to allolactose in E. coli • IPTG, which is a synthetic molecule with a very similar structure to allolactose. IPTG cannot be broken down by E. coli. The scientists grew three cultures of E. coli containing the recombinant plasmid in the same growth medium. The growth medium contained glucose, amino acids, essential vitamins and minerals. The growth medium did not contain lactose. After four hours, either lactose or IPTG at the same concentration was added to two of the cultures of E. coli. As a control, the third culture of E. coli was grown without adding lactose or IPTG. The concentration of recombinant IFN-α in the cultures was measured at different times over a period of 28 hours. The results are shown in . time / hours concentration of IFN-α / μg dm–3 key culture to which IPTG added culture to which lactose added control culture The regulatory sequences of the lac operon contained in the recombinant plasmid are involved in the control of transcription of the gene IFNA2. Explain the role of the gene lacI in the control of transcription of the IFNA2 gene between 0 hours and 4 hours. With reference to , describe the changes in the concentration of recombinant IFN-α in the culture containing IPTG from when IPTG was added at 4 hours to the end of the experiment at 28 hours. Suggest one reason for the difference between the concentration of recombinant IFN-α in the culture at 8 hours in the presence of lactose and the concentration of recombinant IFN-α in the culture at 8 hours in the presence of IPTG. Suggest one reason for the change in the concentration of recombinant IFN-α in the culture containing IPTG from 12 hours to 16 hours. The gene AMPR in the plasmid shown in codes for a protein that provides resistance to the antibiotic ampicillin. Suggest how AMPR allows genetically engineered E. coli containing the recombinant plasmid to be identified. Bacteria can evolve antibiotic resistance through natural processes. Outline how bacteria can evolve to become resistant to antibiotics.
9700_m23_qp_42
THEORY
2023
Paper 4, Variant 2
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Scientists grew bacteria in a medium containing heavy nitrogen, 15N, as the only source of nitrogen. After many generations, all of the bacterial DNA contained heavy nitrogen. These bacteria were then moved from the heavy nitrogen medium into a medium with only light nitrogen, 14N. Some bacteria were collected from each of the next three generations and their DNA was analysed. Hybrid DNA contains both heavy and light nitrogen. Which row shows the correct DNA of the first and third generations?
9700_s20_qp_11
MCQ
2020
Paper 1, Variant 1
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Genetic technology involving the creation of recombinant DNA can be used to treat different human diseases. These include diseases such as diabetes that may have multiple causes and inherited disorders that are caused by a single gene. Outline two different ways of using recombinant DNA technology to treat these diseases. diabetes single gene disorder A new application of recombinant DNA technology uses the genetic modification of a plant to prevent disease. It aims to prevent the most common source of food-borne disease, which is caused by eating food contaminated with pathogenic Escherichia coli bacteria. Scientists genetically modified edible spinach plants to produce colicins. Colicins are antimicrobial proteins that can kill pathogenic E.coli. Colicins are normally made by other bacteria. An experiment was carried out to test this application by spraying an extract of genetically modified (GM) spinach in buffer solution onto raw meat contaminated with pathogenic E.coli. The meat was stored at 10 °C for varying lengths of time before the numbers of viable pathogenic E.coli bacteria were counted. shows the results. time stored at 10 °C / hours log number of viable bacterial cells per gram of meat no treatment Key: buffer solution only buffer solution plus GM spinach extract With reference to , evaluate the effectiveness of using GM spinach spray on raw meat to prevent food-borne disease. Regulatory authorities may not approve the use of GM spinach spray on raw meat to protect consumers. Discuss the concerns that may stop regulatory authorities approving this application of recombinant DNA technology.
9700_s21_qp_42
THEORY
2021
Paper 4, Variant 2
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The potato plant, Solanum tuberosum, is an important food crop. Crop yield is reduced if the leaves of the plant are eaten by the larvae (immature stages) of the Colorado beetle, Leptinotarsa decemlineata. Crop scientists used recombinant DNA technology to create two genetically modified (GM) varieties of potato plant. These plants produce proteins that are poisonous to insects. • GM potato variety A contains two new genes, SN and Bt. • GM potato variety B contains two new genes, SN and OCII. The new varieties were tested by having a constant number of Colorado beetle larvae introduced to the plants at time 0 hours. The number of larvae that were alive after 24, 48 and 72 hours was recorded. The percentage of the larvae that had died in each time interval was calculated. This was repeated for potato plants that had not been genetically modified (non-GM). Table 4.1 shows the percentage of Colorado beetle larvae that had died on the GM potato plant varieties and on non-GM potato plants. Table 4.1 type of potato plant percentage of Colorado beetle larvae that had died 24 h 48 h 72 h GM potato variety A GM potato variety B non-GM potato Suggest what is meant by recombinant DNA technology. Suggest why the scientists created two different types of GM potato plant. State why the scientists also performed the test on non-GM potato plants. Discuss how the results in Table 4.1 provide information that could help to solve the global demand for food.
9700_w23_qp_41
THEORY
2023
Paper 4, Variant 1
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The potato plant, Solanum tuberosum, is an important food crop. Crop yield is reduced if the leaves of the plant are eaten by the larvae (immature stages) of the Colorado beetle, Leptinotarsa decemlineata. Crop scientists used recombinant DNA technology to create two genetically modified (GM) varieties of potato plant. These plants produce proteins that are poisonous to insects. • GM potato variety A contains two new genes, SN and Bt. • GM potato variety B contains two new genes, SN and OCII. The new varieties were tested by having a constant number of Colorado beetle larvae introduced to the plants at time 0 hours. The number of larvae that were alive after 24, 48 and 72 hours was recorded. The percentage of the larvae that had died in each time interval was calculated. This was repeated for potato plants that had not been genetically modified (non-GM). Table 4.1 shows the percentage of Colorado beetle larvae that had died on the GM potato plant varieties and on non-GM potato plants. Table 4.1 type of potato plant percentage of Colorado beetle larvae that had died 24 h 48 h 72 h GM potato variety A GM potato variety B non-GM potato Suggest what is meant by recombinant DNA technology. Suggest why the scientists created two different types of GM potato plant. State why the scientists also performed the test on non-GM potato plants. Discuss how the results in Table 4.1 provide information that could help to solve the global demand for food.
9700_w23_qp_43
THEORY
2023
Paper 4, Variant 3
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shows the area of land that was used to grow genetically modified (GM) crops in the USA, Brazil, India and China from 2004 to 2015. year area of land used to grow GM crops / million hectares 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 USA Brazil India China key Suggest reasons why the area of land used to grow GM crops in the USA is greater than the area of land used to grow GM crops in Brazil. Describe the differences in the area of land that was used to grow GM crops in China and the area of land that was used to grow GM crops in India, over the time shown in . Genetic modifications in crops can provide resistance to insect pests. Bt maize is one type of GM crop that has been produced to be resistant to insect pests. State two benefits to farmers of insect resistance in crops. Describe the difference between Bt maize and non-GM maize that explains why Bt maize is resistant to insects. State two reasons why people may have objections to the growth of insect-resistant GM crops. In 2015, the percentage of the USA population that objected to the use of GM crops was lower than in 2005. Suggest why a smaller percentage of the USA population objected to the use of GM crops in 2015.
9700_m19_qp_42
THEORY
2019
Paper 4, Variant 2
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Gene technology has many uses including the production of substances such as insulin. Outline what is meant by gene technology. Explain why genes for enzymes that produce fluorescent substances are used as makers in gene technology. There is much controversy throughout the world regarding the use of genetically modified (GM) crops. Suggest two advantages of growing GM rice with an enhanced vitamin A content. Suggest two disadvantages of growing GM crops.
9700_s10_qp_42
THEORY
2010
Paper 4, Variant 2
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Questions Discovered
107