Cambridge O Level Biology · Syllabus 5090 · Biotechnology and Genetic Modification
Genetic modification
What is Genetic modification?
Changing the genetic material of an organism by removing, changing or inserting individual genes. The change is made directly to DNA rather than by choosing which organisms reproduce, and it can move a gene between species because the genetic code is essentially the same in all organisms. A modified organism may express the inserted gene and produce a protein, and therefore a characteristic, that it could not produce before. Genetic modification is one technique within biotechnology, not a synonym for it, and it is not the same as selective breeding, in which parents with desirable features are chosen and bred over many generations without any gene being moved.
This definition is part of the Biotechnology and Genetic Modification chapter in Cambridge O Level Biology.
Genetic modification in context
Biotechnology is the use of living organisms, cells or enzymes to make useful products. Yeast respires anaerobically, converting glucose to ethanol and carbon dioxide: the carbon dioxide raises bread dough, and the ethanol is the product collected in ethanol manufacture. Bacteria are chosen for industrial production because they reproduce rapidly, can make complex molecules, contain plasmids that can receive selected genes, and raise fewer ethical concerns than using animals. They are grown in fermenters, in which temperature, pH, oxygen, nutrient supply and waste products are all controlled. Isolated enzymes do industrial jobs of their own — proteases and lipases in biological washing powders, pectinase in fruit juice, lactase in lactose-free milk. Genetic modification is changing an organism's genetic material by removing, changing or inserting individual genes; inserting the human insulin gene into bacterial DNA lets bacteria make human insulin, and inserting genes into crops can give herbicide resistance, insect-pest resistance or increased vitamin content — each with benefits and risks that have to be weighed rather than declared.
Genetic modification is changing the genetic material of an organism by removing, changing or inserting individual genes.
Common mistakes with Genetic modification
- “Biotechnology means genetic modification.” Why wrong It collapses a whole field into one of its techniques, and makes it impossible to answer a question about bread or washing powder.
- “The whole human genome is put into the bacterium.” Why wrong One gene is transferred. The definition of genetic modification says individual genes, and a plasmid could not carry a genome in any case.
- “All biotechnology is genetic modification.” Why wrong It collapses a whole field into one technique. Bread, brewing and every enzyme application in this chapter involve no gene transfer at all. Say instead Biotechnology is the use of living organisms, cells or enzymes to make useful products. Genetic modification is one technique used within it.
- “Selective breeding is a kind of genetic modification.” Why wrong No gene is moved in selective breeding. The population changes because of which organisms reproduced, over many generations. Say instead Selective breeding chooses parents with desired features and breeds them; genetic modification directly inserts, removes or changes a gene.
Examiner tips on Genetic modification
- A sentence that gains a mark in an evaluation. “This risk is not unique to genetic modification: repeated use of a single insecticide selects for resistance in the same way.” It shows you are comparing the technology with the realistic alternative rather than with a perfect one, which is what evaluate asks for.
Questions students ask about Genetic modification
What is biotechnology?
Biotechnology is the use of living organisms, cells or enzymes to make useful products or to carry out useful processes. It includes using yeast to make bread and ethanol, growing bacteria in industrial fermenters, and using isolated enzymes such as proteases, pectinase and lactase. Genetic modification is one technique used within biotechnology, not another name for it.
What is genetic modification?
Genetic modification is changing the genetic material of an organism by removing, changing or inserting individual genes. The change is made directly to DNA, and because the genetic code is essentially the same in all organisms a gene can be transferred between species and still produce the same protein.
Is genetic modification safe?
That question cannot be answered for the technology as a whole. Each application has its own mechanism, its own benefits and its own risks, and a scientific answer names them and states what a judgement depends on. “All GM is unsafe” and “GM has no risks” are both unsupported absolutes, and neither earns credit in an evaluation question.
How is genetic modification different from selective breeding?
Genetic modification changes DNA directly, inserting, removing or changing one selected gene, and can transfer a gene between species in a single generation. Selective breeding chooses parents with desired features and breeds them, so many genes are inherited together, the change happens over many generations, and it works only between organisms that can breed with each other. Neither technique is risk-free.