Genetic Technology
Genetic technology applies our understanding of DNA and genes to solve real problems in medicine, agriculture and industry. This chapter covers genetic engineering, where genes are deliberately transferred between organisms, and the wider field of biotechnology, which uses living organisms or their products on an industrial scale, together with the benefits each brings and the questions they raise.
You should be able to describe worked examples in detail rather than name-drop them, such as how a human gene is inserted into a bacterium to produce insulin, or how a herbicide-resistant gene is introduced into a crop plant. Explaining the steps of a process earns more marks than simply stating that genetic engineering 'helps agriculture'.
Beyond the two core content standards, exam questions often extend into related applications you should recognise: gene therapy, which inserts a working copy of a gene to treat a genetic disease; DNA fingerprinting, which uses unique patterns in a person's DNA for identification; and cloning, which produces a genetically identical copy of an organism or of specific cells.
Because this chapter touches ethics and safety directly, a strong answer weighs a specific benefit against a specific concern rather than giving a one-sided view. Practise writing balanced short paragraphs that state a benefit, a concern, and a brief justification, since this structure matches how essay questions on this topic are usually marked.
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Content standards in this chapter
- 28.1 Genetic Engineering
- 28.2 Biotechnology
Key concepts
- Genetic engineering
- Genetic engineering is the deliberate, direct alteration of an organism's genes in the laboratory, most often by transferring a useful gene from one organism into another so the recipient gains a new characteristic it did not have before. This differs from selective breeding, which only works with genetic variation that already exists in a population. The transferred gene can come from a bacterium, a plant or an animal, and it is moved across species boundaries for a specific purpose.
- Recombinant DNA
- Recombinant DNA is formed by cutting a gene from one source and joining it into DNA from another, often a bacterial plasmid, using specific enzymes. Once inserted into a host cell, the recombinant DNA is copied and read along with the host's own genes. The plasmid acts as a vector, a carrier that ferries the new gene into the host and allows it to be copied whenever the host cell divides.
- Applications
- Practical applications include bacteria engineered to produce human insulin and growth hormone, crops modified for pest resistance, herbicide tolerance or improved nutrient content, and enzymes engineered for use in industrial processes such as detergents and food production. Each application starts from the same basic technique: identifying a useful gene, then transferring and expressing it in a new host. Bt cotton, for example, is engineered to produce a natural toxin against a specific pest caterpillar, making it one of the most widely grown genetically modified crops in the world.
- Biotechnology
- Biotechnology is the broader use of living organisms, cells or their products for a practical purpose, and includes traditional processes such as fermentation for bread and yoghurt alongside modern techniques such as genetic engineering and enzyme technology used at an industrial scale. Genetic engineering can therefore be described as one modern branch within the wider field of biotechnology, not a separate subject.
- Benefits
- Benefits include cheaper, more reliable production of medicines such as insulin and vaccines, higher and more resilient crop yields that support food security, and new treatments for some genetic diseases through approaches such as gene therapy. Industrial enzymes produced through biotechnology can also make manufacturing processes faster and use less energy.
- Ethical and safety issues
- Concerns include unknown long-term effects of a genetically modified organism on health or on other species in the environment, unequal access to expensive new technology between rich and poor countries, and broader questions about how far it is acceptable to alter living things. A strong exam answer names a specific concern, such as an inserted gene spreading to a wild relative of a crop, rather than describing the worry in general terms.
- Gene therapy
- Gene therapy treats a genetic disease by inserting a working copy of a gene into a patient's cells to replace or support a faulty one. It targets specific cells rather than the whole body, so it does not automatically change every cell or get passed on to the patient's children. Research in this field is still active, and the number of widely approved gene therapy treatments remains small compared with conventional medicine.
- Genetically modified (GM) crops
- A genetically modified crop has had a useful gene inserted, for example for resistance to a specific pest or tolerance of a herbicide, or for higher levels of a nutrient. Each GM crop is tested and regulated individually rather than judged as automatically safe or unsafe as a category.
- DNA fingerprinting
- DNA fingerprinting compares the pattern of repeated DNA sequences that is unique to each individual, other than identical twins, to identify a person or establish a biological relationship. It does not involve changing any genes, only reading and comparing patterns that already exist. Close relatives share more of these patterns than unrelated people, which is what makes the technique useful for paternity testing.
- Cloning
- Cloning produces a genetically identical copy of an organism or of specific cells. Reproductive cloning creates a whole new individual, as with the sheep Dolly, while therapeutic cloning aims to produce matching cells or tissue for medical treatment rather than a new organism. Because a clone shares the same genes as the original, it does not automatically share every observable characteristic, since environment also plays a part.
How this chapter is examined
SPM Biology is assessed over three papers. Paper 1 has 40 objective questions (40 marks) in 1 hour 15 minutes; Paper 2 carries 100 marks across Sections A, B and C in 2 hours 30 minutes; Paper 3 is the practical, testing science process skills. Content from this chapter can appear in any of them, so lessons drill recall for Paper 1 and structured answers for Paper 2.
Common exam angles
- Giving a detailed worked example of genetic engineering rather than only naming the technique.
- Explaining step by step how bacteria are used to produce a human protein such as insulin.
- Weighing a specific benefit of genetic technology against a specific concern in a balanced answer.
- Explaining how gene therapy could correct a genetic disease at the cell level.
- Describing why DNA fingerprinting can identify one individual from a DNA sample.
- Distinguishing reproductive cloning from therapeutic cloning and their different purposes.
Common mistakes
What students write: Confusing genetic engineering with selective breeding.
What earns the mark: Genetic engineering directly changes genes in the laboratory; selective breeding chooses which organisms to breed over generations. Genetic engineering can also transfer a gene between very different species, something natural selective breeding cannot achieve.
What students write: Saying insulin is made from human pancreas cells.
What earns the mark: Human insulin is now commonly made by bacteria that have been given the human insulin gene. This method produces insulin in large, purer quantities compared with the older method of extracting it from animal organs.
What students write: Writing that all genetically modified food is unsafe.
What earns the mark: Genetically modified crops are tested; the question is about specific risks and ethics, not a blanket claim. Each new crop is assessed on its own inserted gene and observed effects, not generalised from other GM crops.
What students write: Treating biotechnology as only genetic engineering.
What earns the mark: Biotechnology is broader, including fermentation, enzyme technology and vaccine production, not just gene editing. Some biotechnology processes, such as fermentation to make bread, have been used since long before genetic engineering existed.
What students write: Believing gene therapy changes a person's entire genome instantly.
What earns the mark: Gene therapy targets a specific faulty gene in particular cells; it does not automatically alter every cell in the body or every gene a person carries.
What students write: Saying DNA fingerprinting changes or edits a person's genes.
What earns the mark: DNA fingerprinting only reads and compares existing patterns in a person's DNA; no gene is added, removed or altered in the process.
What students write: Treating reproductive and therapeutic cloning as the same procedure.
What earns the mark: Reproductive cloning produces a whole new genetically identical organism, while therapeutic cloning aims to produce cells or tissue for treatment without creating a new individual. Only reproductive cloning results in a new organism that can grow, develop and live independently.
What students write: Assuming a GM crop is automatically dangerous because it is genetically modified.
What earns the mark: Safety depends on the specific gene inserted and its effects, which is why each genetically modified crop is tested and regulated individually rather than judged as a category. Two GM crops carrying different inserted genes can carry very different risk profiles.
Study this chapter
Frequently asked questions
What is genetic engineering?
How is insulin produced using bacteria?
What are the concerns about genetic technology?
What is gene therapy?
How does DNA fingerprinting identify a person?
Source:SRC-DSKP-EN, SRC-FORMAT
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