Biology 9700 · AS & A Level · Genetically modified organisms in agriculture
Genetically modified organisms in agriculture — practice question
There are several distinct strains of the soil bacterium $Bacillus\ thuringiensis$. Each strain makes a slightly different type of Cry-protein, and these proteins are poisonous to insects. Some cotton varieties, known as Bt cotton, have been genetically engineered to produce one of these proteins, Cry1Ac. This protein acts specifically to kill the larvae of butterflies and moths, including the cotton bollworm, $Helicoverpa\ zea$, which is a serious pest of cotton crops.
The genetically modified cotton carries a ‘genetic package’ that includes:
• the gene that codes for Cry1Ac, the Bt protein
• a promoter
• a herbicide resistance gene used as a marker.
(a(i))[2]
Suggest the advantages of using, in Bt cotton, the gene coding for Cry1Ac, rather than a gene coding for another type of Cry-protein.
(a(ii))[2]
Explain the reason a promoter is included in the genetic package.
(a(iii))[3]
Suggest how the herbicide resistance gene may be used as a genetic marker.
(b(i))[2]
With reference to Table 4.1, compare the costs of growing Bt cotton with those of growing non-GM cotton.
(b(ii))[1]
Table 4.1 shows that farmers growing Bt cotton have a higher net income than farmers growing non-GM cotton. Use the information in the table to suggest one reason why some farmers in India grow non-GM cotton instead of Bt cotton.
(c)[3]
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.
Worked solution & mark scheme
This 13-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Targets only particular insect pests” …