4.6.2.4b - Genetic Engineering Applications and Risks
Genetic engineering can give organisms useful characteristics, but AQA is especially interested in how those uses are judged. In this lesson, the process is only a brief prerequisite: the main work is explaining applications in agriculture and medicine, then weighing possible benefits, risks and objections using evidence.
The prerequisite idea
Genetic engineering means modifying the genome of an organism by introducing a gene from another organism. The introduced gene can give the organism a desired characteristic.
Genetic engineering
Genetic engineering is a process that modifies the genome of an organism by introducing a gene from another organism to give a desired characteristic.
At this GCSE level, the useful reminder is that genes can be cut out from the chromosomes of humans or other organisms and transferred to cells of another organism. This lesson does not need the full Higher-tier step sequence; the focus here is what genetic engineering can be used for and how its benefits and risks are judged.
A crop that has had its genes modified in this way is called a genetically modified crop, or GM crop. The word modified does not automatically mean useful, harmful or safe. It means the crop's genetic material has been changed, so the application must be judged by the characteristic added and the evidence about benefits and risks.
GM crop
A genetically modified crop is a crop that has had its genes modified using genetic engineering.
Use the scale carefully. A gene is a section of DNA. The genome is all of the genetic material of an organism. Genetic engineering changes the organism's genome by adding a gene, and that gene may cause cells to make a useful protein or show a useful characteristic.
Agricultural applications
Genetic engineering can be used in agriculture to produce crops with useful characteristics. AQA names crops engineered to be resistant to diseases or to produce bigger, better fruits. It also names GM crops resistant to insect attack or to herbicides.
These applications are not all the same. A disease-resistant crop may survive infection better. An insect-resistant crop may be damaged less by insect pests. A herbicide-resistant crop can survive a herbicide that kills weeds around it. A crop producing bigger or better fruits may give more useful food from the same area of land.
The common agricultural aim is increased yield. Yield means the amount of useful crop produced, often from a given area of land. GM crops generally show increased yields because more plants survive, less crop is lost, or more useful product is produced by each plant.
| GM crop characteristic | Possible agricultural advantage |
|---|---|
| Disease resistance | Fewer plants lost to disease |
| Insect resistance | Less damage from insect pests |
| Herbicide resistance | Weeds can be controlled while the crop survives |
| Bigger or better fruits | More useful food may be produced |
Do not write only "GM crops are better". A strong answer names the characteristic and links it to the advantage. For example: "An insect-resistant GM crop may have less insect damage, so more crop can be harvested and yield may increase."
Medical applications
Genetic engineering can also be useful in medicine. AQA's named example is bacterial cells genetically engineered to produce useful substances such as human insulin to treat diabetes.
Insulin is a hormone used to treat some people with diabetes. Bacteria reproduce quickly and can be grown in large numbers, so genetically engineered bacterial cells can act like tiny production systems for a useful human protein. The GCSE point is the application: the bacteria have been modified so they produce a useful substance.
Insulin
Insulin is a hormone that helps control blood glucose concentration and can be used to treat diabetes.
AQA also says modern medical research is exploring the possibility of genetic modification to overcome some inherited disorders. Keep this cautious. Some inherited disorders are caused by faulty alleles, so changing DNA in affected cells could, in some cases, help cells work more normally. However, this is an area of medical research and treatment decisions must consider safety, effectiveness and ethical issues.
The medicine example is different from GM crops. In insulin production, the genetically engineered bacteria are used to make a medicine. The patient does not become genetically engineered by taking insulin.
Benefits and risks
AQA expects you to explain potential benefits and risks of genetic engineering in agriculture and medicine. Potential means possible; it does not mean every example will definitely have the same outcome.
Agricultural benefits often link to food production. GM crops may produce higher yields, so more food can be harvested. Insect-resistant crops may need fewer insecticide sprays in some situations. Disease-resistant crops may reduce crop loss. Herbicide-resistant crops may make weed control easier.
Agricultural risks and concerns often link to ecosystems. If herbicide use removes many wild plants from fields, populations of wild flowers may fall. If there are fewer wild flowers, insects that feed on them or use them for shelter may also decrease. GM crops may also pass introduced genes to closely related wild plants or non-GM crops if they cross breed.
Human health concerns must be worded carefully. AQA says some people feel the effects of eating GM crops on human health have not been fully explored. Do not turn that into a stronger claim such as "GM crops are dangerous". A balanced answer says that some people are concerned about possible long-term effects, so individual GM foods need careful safety assessment.
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