9700 · 19.3
Genetically modified organisms in agriculture flashcards
Revision flashcards for Cambridge 9700 Genetically modified organisms in agriculture (syllabus 19.3). Flip, recall, then mark a real past-paper question.
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What is the bacterium from which the pest-resistance gene in Bt maize is isolated?
Bacillus thuringiensis (Bt).
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What is the nutritional enhancement in Golden Rice designed to combat?
Vitamin A deficiency, which can cause blindness and immune system problems.
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Name a common bacterial vector used to transfer genes into plant cells.
Agrobacterium tumefaciens, which transfers a section of its Ti plasmid into the plant genome.
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What is 'gene flow' in the context of GM crops?
The transfer of transgenes from genetically modified crops to wild relatives or non-GM crops via cross-pollination.
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Why are 'refuges' of non-GM crops planted near fields of Bt crops?
To slow the evolution of resistance in pests. Mating between susceptible pests from refuges and rare resistant pests from the Bt crop produces heterozygous offspring that are usually still killed by the Bt toxin.
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What is the name of the physical method that uses DNA-coated metal particles to transform plant cells?
The gene gun method, also known as biolistics or microprojectile bombardment.
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What molecule is Golden Rice engineered to produce in its endosperm?
Beta-carotene, a precursor to Vitamin A, which gives the rice its characteristic yellow-orange colour.
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State one potential disadvantage of using herbicide-tolerant GM crops.
The evolution of herbicide-resistant weeds ('superweeds') due to strong selection pressure from repeated herbicide application.