1[1 mark]
What is genetic engineering?
- Choosing parents with desired characteristics to breed together.
- Growing many identical plants from small pieces of tissue.
- Modifying the genome of an organism to introduce desirable characteristics.
- Using living organisms to control pests.
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Answer: C C (1)
2[2 marks]
Bacteria can be genetically engineered to make human insulin. Describe what is done to the bacteria and the result.
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- the human gene for insulin is inserted into the genome / DNA of the bacteria (1)
- the bacteria can make human insulin (1)
3
Higher tier
[3 marks]Describe the roles of restriction enzymes and ligase in genetic engineering.
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- restriction enzyme cuts DNA at a specific base sequence (1)
- leaving sticky ends (1)
- ligase joins the DNA / gene into the vector (1)
4
Higher tier
[4 marks]Describe the main stages in inserting a gene into a bacterial plasmid vector.
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- cut the gene out using a restriction enzyme (1)
- cut the plasmid with the same restriction enzyme, so sticky ends match (1)
- mix the gene and plasmid, and use ligase to join them (1)
- insert the plasmid (vector) into the bacterium (1)
5
Triple only
[3 marks]Crop plants can be genetically engineered with a gene from Bacillus thuringiensis. Explain how this benefits a farmer.
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- the gene codes for a toxin that kills insect pests (1)
- so less of the crop is eaten / damaged, giving a higher yield (1)
- less insecticide needs to be used (1)
6
Triple only
[2 marks]Give two disadvantages of growing GM crops.
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- possible risk to human health (1)
- genes may spread to wild plants / the toxin may harm other insects (1)
- seeds are expensive / farmers must buy new seeds (1)
- some people think it is wrong (1)
- Max 2