GM organisms and crop plantsSpec 4.12B
In short
GM crops contain genes from other species. In Bt crops, a gene from the bacterium Bacillus thuringiensis makes the plant produce a toxin that kills many insect pests. This gives higher yields and means less insecticide is sprayed. Disadvantages include possible health risks, genes spreading to wild plants, expensive seeds and pests evolving resistance to the toxin.
A well-known example is the introduction of a gene from the bacterium Bacillus thuringiensis (Bt) into crop plants. The gene codes for a toxin that kills many insect pests. Plants with the gene make the toxin themselves and so have insect resistance.
| Advantages | Disadvantages |
|---|---|
| Less crop is lost to pests, so yields are higher | Possible risk to human health, which some people worry about |
| Less insecticide needs to be sprayed, which saves money and reduces damage to other organisms | Genes may spread to wild plants, and the toxin might harm other insects |
| Crops can be given extra characteristics, such as greater nutritional value or resistance to disease | GM seeds can be expensive, and farmers may have to buy new seeds each year |
| More food can be produced for a growing population | Concerns that it is wrong or unnatural to change organisms' genes |
| Crops with a gene for herbicide resistance can be sprayed to kill weeds without harming the crop | Insect pests may evolve resistance to the Bt toxin by natural selection |
Structure 'advantages and disadvantages' answers as a balanced argument, then add a conclusion. Link each point to the crop, the farmer, people or the environment.
Quick check
What is genetic engineering?
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Modifying the genome of an organism to introduce desirable characteristics.
What does a GM organism contain that a normal organism does not?
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A gene transferred from another organism.
Give one example of a desirable characteristic introduced by genetic engineering.
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For example, bacteria making human insulin, or crop plants resistant to insects.
Written and checked against the Edexcel GCSE Biology (1BI0) specification · Updated October 2026