8.4.6The Control of Gene Expression (A Level only)
Uses of Recombinant DNA Technology — AQA A Level Biology 7402 Revision Notes & Topical Questions
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8.4.6 Uses of Recombinant DNA Technology — AQA A Level Biology 7402 notes: Describe uses of recombinant DNA technology in medicine, agriculture and industry, and evaluate the benefits and concerns.Recombinant bacteria or yeast produce human proteins in bulk.Examples include human…
- human insulin
- Gene therapy
- Pest resistance
- Herbicide resistance
- Improved nutrition
- Shelf-life and tolerance
Section 1 of 8Medicine: proteins and vaccines
Recombinant bacteria or yeast produce human proteins in bulk.
- which could trigger immune reactions), human growth hormone, and clotting factor VIII for haemophilia.
- (replacing blood-derived product that risked passing on viruses)
- which is safe because no viral genetic material is present and so the virus cannot replicate.
Section 2 of 8Medicine: gene therapy
Gene therapy treats genetic disease by inserting a functional allele into the patient's cells, using viral vectors or liposomes.
- and the risk that the allele is inserted into the wrong place, disrupting a gene or activating an oncogene.
Section 3 of 8Agriculture
Genes are often moved into plants using Agrobacterium tumefaciens, a bacterium whose plasmid transfers DNA into plant cells.
Section 4 of 8Industry
Enzymes made by recombinant microorganisms are used in detergents, in food processing (for instance chymosin for cheese, replacing calf rennet, so the product is suitable for vegetarians) and in biofuel production. Microbes can also be engineered to break down pollutants such as oil or to make plastics from renewable material.
Section 5 of 8Benefits and concerns
| Possible benefits | Possible concerns |
|---|---|
| Reliable, large-scale supply of human proteins | Cost and patenting can restrict access in poorer countries |
| Higher yields, less pesticide | Gene flow to wild relatives, creating resistant weeds |
| Improved nutrition | Effects on non-target insects and biodiversity |
| Treatment of inherited disease | Risk of a gene being inserted in the wrong place, causing cancer |
| Fewer animal products needed | Farmers become dependent on companies for seed |
Ethical views vary. Some argue that it is wrong to alter the genomes of organisms or that long-term effects are unknown; others argue that the benefits to human health and food security outweigh the risks. Credit in exams is given for a balanced evaluation that uses specific examples.
Section 6 of 8Exam-style questions
Give two advantages of producing human insulin using genetically modified bacteria rather than extracting it from pigs. [2]2 marks
1. Human insulin has the same structure as the person's own, so there is less chance of an immune response or reduced effectiveness. 2. Production is faster, larger scale and cheaper, and avoids the ethical objections to using animals.
Evaluate the use of genetically modified crops containing a Bt toxin gene. [4]4 marks
Benefits: less insecticide is needed, lowering costs and harm to non-target organisms; yield is higher as less is lost to pests. Concerns: target insects may evolve resistance; the gene could spread to wild plants; there may be unknown effects on food chains. Conclusion: the benefits need to be weighed against long-term monitoring of the risks.
Section 7 of 8Key terms
| Term | Meaning |
|---|---|
| Gene therapy | Treating disease by altering a patient's genes |
| Somatic | Body cells rather than gametes |
| Bt toxin | Insecticidal protein from Bacillus thuringiensis |
| GM crop | Crop containing a gene from another organism |
| Agrobacterium tumefaciens | Bacterium used to transfer genes into plants |
| Golden Rice | Rice engineered to produce beta-carotene |
Section 8 of 8Exam technique
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