Flashcards · Biology · Selective Breeding and Genetic Engineering
GM Crops
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What is a GM crop?
A crop with genes changed by genetic engineering.
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Which bacterium is the source of the insect resistance gene?
Bacillus thuringiensis.
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What does the Bt gene make?
A toxin that kills certain insect larvae.
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How does a Bt crop protect itself?
The plant makes the toxin, so insects that eat it are killed.
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Name two Bt crops.
Maize and cotton.
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Give two advantages of GM crops.
Higher yield, and less spraying with insecticide.
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Why might insects become resistant to Bt crops?
Natural selection favours the insects that survive the toxin.
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What is a refuge?
A part of the field with non-GM crop, to keep non-resistant insects.
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Why might GM crops harm biodiversity?
The toxin might harm non-target insects, or the crop might replace other plants.
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What is gene transfer?
The spread of a modified gene to other plants, such as wild relatives, by pollen.
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Why are GM seeds expensive?
The seed is patented, and often has to be bought new each year.
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What is golden rice designed to prevent?
Vitamin A deficiency.
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Has any harm to human health been found from GM crops?
No evidence of harm has been found, although some people want more long-term studies.
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Give an example of a GM crop other than Bt.
Herbicide-resistant soy, or golden rice.
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Why does a Bt crop need less insecticide?
It makes its own protection.
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Common mistake about Bt crops?
Saying that the toxin is made by the farmer. The plant itself makes it, from the transferred gene.