19.3. Genetically modified organisms in agriculture
A subsection of Biology, 9700, through 19. Genetic technology
Listing 10 of 27 questions
There are many different strains of the soil bacterium Bacillus thuringiensis. Each produces slightly different types of Cry-proteins, which are toxic to insects. Some types of cotton, known as Bt cotton, have been genetically modified to produce one of these proteins, Cry1Ac. This protein acts specifically to kill the larvae of butterflies and moths, including the cotton bollworm, Helicoverpa zea, a serious pest of cotton crops. The genetically modified cotton contains a ‘genetic package’ that includes: • the gene coding for Cry1Ac, the Bt protein • a promoter • a herbicide resistance gene that is used as a marker. Suggest the advantages of using, in Bt cotton, the gene coding for Cry1Ac, rather than one of the genes coding for other types of the Cry-protein. Explain why a promoter is included in the genetic package. Suggest how the herbicide resistance gene can be used as a genetic marker. Table 4.1 shows information about the cultivation of Bt cotton and non-GM cotton by farmers in India in 2002–2003. Table 4.1 Bt cotton non-GM cotton mean yield of cotton / kg ha–1 seed cost / rupees ha–1 insecticide cost / rupees ha–1 net income / rupees ha–1 With reference to Table 4.1, compare the costs involved in growing Bt cotton with the costs involved in growing non-GM cotton. Table 4.1 shows that farmers who grow Bt cotton have a higher net income than those who grow non-GM cotton. Use the information in the table to suggest one reason why some farmers in India choose to grow non-GM cotton, rather than Bt cotton. In one region of India, Andhra Pradesh, a severe drought in 2002–2003 meant that Bt cotton grew less well than other varieties of cotton that were better adapted for the conditions. Suggest how a variety of Bt cotton that is better adapted to dry conditions could be produced from the existing varieties of Bt cotton, without using gene technology.
9700_w17_qp_41
THEORY
2017
Paper 4, Variant 1
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There are many different strains of the soil bacterium Bacillus thuringiensis. Each produces slightly different types of Cry-proteins, which are toxic to insects. Some types of cotton, known as Bt cotton, have been genetically modified to produce one of these proteins, Cry1Ac. This protein acts specifically to kill the larvae of butterflies and moths, including the cotton bollworm, Helicoverpa zea, a serious pest of cotton crops. The genetically modified cotton contains a ‘genetic package’ that includes: • the gene coding for Cry1Ac, the Bt protein • a promoter • a herbicide resistance gene that is used as a marker. Suggest the advantages of using, in Bt cotton, the gene coding for Cry1Ac, rather than one of the genes coding for other types of the Cry-protein. Explain why a promoter is included in the genetic package. Suggest how the herbicide resistance gene can be used as a genetic marker. Table 4.1 shows information about the cultivation of Bt cotton and non-GM cotton by farmers in India in 2002–2003. Table 4.1 Bt cotton non-GM cotton mean yield of cotton / kg ha–1 seed cost / rupees ha–1 insecticide cost / rupees ha–1 net income / rupees ha–1 With reference to Table 4.1, compare the costs involved in growing Bt cotton with the costs involved in growing non-GM cotton. Table 4.1 shows that farmers who grow Bt cotton have a higher net income than those who grow non-GM cotton. Use the information in the table to suggest one reason why some farmers in India choose to grow non-GM cotton, rather than Bt cotton. In one region of India, Andhra Pradesh, a severe drought in 2002–2003 meant that Bt cotton grew less well than other varieties of cotton that were better adapted for the conditions. Suggest how a variety of Bt cotton that is better adapted to dry conditions could be produced from the existing varieties of Bt cotton, without using gene technology.
9700_w17_qp_43
THEORY
2017
Paper 4, Variant 3
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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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Questions Discovered
27