How does genetic engineering work, and what are its benefits and risks?
Describe genetic engineering and its main stages, the advantages and disadvantages of producing GM organisms and of agricultural solutions to feeding a growing population, and evaluate the benefits and risks.
A focused answer to Edexcel GCSE Biology 4.10 to 4.14, covering the stages of genetic engineering, the production of GM organisms, agricultural solutions such as fertilisers and biological control, and the evaluation of benefits and risks.
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What this dot point is asking
Edexcel statements 4.10 to 4.14 want you to describe genetic engineering and its main stages, explain the advantages and disadvantages of producing GM organisms (4.12B Biology only) and of agricultural solutions such as fertilisers and biological control (4.13B Biology only), and evaluate the benefits and risks of genetic engineering and selective breeding. "Evaluate" means weigh both sides and reach a judgement.
What genetic engineering is
Examples include bacteria engineered to make human insulin, crops engineered to resist insect pests or herbicides, and rice engineered to contain extra vitamin A (golden rice).
The main stages of genetic engineering
The same restriction enzyme is used on the gene and the vector so their sticky ends match and join correctly.
Agricultural solutions (Biology only)
To feed a growing population, farmers also use other methods, each with trade-offs:
- Fertilisers add mineral ions (such as nitrates) to soil, increasing crop yields. But excess fertiliser can run off into rivers and lakes, causing eutrophication (algal blooms that lead to the death of aquatic life).
- Biological control uses a natural predator or parasite to control a pest instead of chemical pesticides. This avoids chemical pollution and the pest cannot easily become resistant, but the introduced species could itself become a pest or upset the food web.
Evaluating benefits and risks
The specification asks you to evaluate both genetic engineering and selective breeding. A strong answer gives points on both sides and a judgement.
- Benefits: higher yields and food security, pest and disease resistance, reduced use of chemical pesticides, crops with added nutrients to fight malnutrition, and medical products such as insulin.
- Risks: GM genes might spread to wild plants, biodiversity could fall if one engineered variety dominates, there may be unknown long-term effects on health or ecosystems, and farmers may become dependent on seed companies. There are also ethical concerns about modifying organisms.
Try this
Q1. Name the type of enzyme used to cut a gene out of DNA in genetic engineering. [1 mark]
- Cue. A restriction enzyme.
Q2. Give one benefit and one risk of growing GM crops. [2 marks]
- Cue. Benefit: higher yield, pest resistance or added nutrients. Risk: gene spread to wild plants, reduced biodiversity, or unknown long-term effects.
Exam-style practice questions
Practice questions written in the style of Pearson Edexcel exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Edexcel 20194 marksDescribe the main stages of genetic engineering used to produce a crop plant with a useful gene.Show worked answer →
A 4-mark describe question rewards the stages in order, using the correct tools.
- The useful gene is identified and cut out of the donor organism's DNA using a restriction enzyme (an enzyme that cuts DNA).
- The gene is inserted into a vector, such as a plasmid or a virus, using ligase enzyme to join the DNA.
- The vector carries the gene into the cells of the crop plant.
- The modified cells are grown so that the new gene is expressed and the plant has the useful characteristic.
Markers reward cutting the gene with a restriction enzyme, inserting it into a vector (plasmid), transferring it into the host cell and the host expressing the gene. Vague answers that scientists put a gene in score little without the enzymes and vector.
Edexcel 20216 marksEvaluate the use of genetically modified crops to help feed a growing human population.Show worked answer →
A 6-mark evaluate question rewards balanced points and a judgement.
Advantages: GM crops can give higher yields, resist insect pests (for example using a gene from Bacillus thuringiensis), tolerate herbicides, or contain extra nutrients (such as vitamin A in golden rice), helping to feed more people and reduce malnutrition.
Disadvantages: there are concerns that GM genes could spread to wild plants, that biodiversity might fall, that there could be unknown long-term effects on health, and that farmers may become dependent on companies selling the seeds.
A good answer weighs these up and reaches a supported conclusion, for example that GM crops can help if carefully regulated and monitored. Markers reward at least one advantage, one disadvantage, and a justified judgement.
Related dot points
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- Describe the work of Darwin and Wallace and explain the theory of evolution by natural selection, including how the emergence of resistant organisms such as antibiotic-resistant bacteria supports the theory.
A focused answer to Edexcel GCSE Biology 4.1B to 4.3, covering the work of Darwin and Wallace, the theory of evolution by natural selection, and how antibiotic-resistant bacteria provide evidence for it.
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A focused answer to Edexcel GCSE Biology 3.4 to 3.10B, covering DNA as a double helix polymer, the genome and genes, DNA extraction, and how the base sequence controls protein synthesis by transcription and translation.
- Explain the key genetic terms, use genetic diagrams, Punnett squares and pedigrees for monohybrid inheritance and sex determination, and calculate outcomes as ratios, percentages and probabilities.
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Sources & how we know this
- Pearson Edexcel GCSE (9-1) Biology (1BI0) specification — Pearson (2016)