Genetic Engineering
Recap Genetic Engineering for GCSE Biology with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA, Edexcel and OCR. Genetic engineering transfers genes from one organism to another; be ready to weigh the benefits and concerns of GM crops.
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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.
Topic overview
Genetic engineering is a process in which genes from the chromosomes of one organism are cut out and transferred to the cells of another.
Enzymes are used to isolate the required gene, which is then inserted into a vector — usually a bacterial plasmid or a virus. The vector carries the gene into the cells of the target organism. If this is done at an early stage of development, the organism develops with the desired characteristic.
Uses include crops resistant to disease or producing bigger fruits, and bacteria modified to produce human insulin for treating diabetes. Concerns exist about effects on wild flowers and insects, and about long-term effects on human health.
Revision notes
The method
Enzymes are used to isolate the required gene from one organism's chromosome.
The gene is inserted into a vector, usually a bacterial plasmid or a virus. The vector inserts the gene into the cells of the target organism at an early stage of development, so the organism develops with the desired characteristic.
Uses
Genetically modified crops resistant to insect attack or herbicides, giving increased yields.
Crops with improved nutritional value, such as golden rice. Bacteria genetically engineered to produce human insulin, used to treat diabetes.
Concerns
Some people worry that GM crops may affect populations of wild flowers and insects.
The effects on human health of eating GM crops have not been fully explored. There are also concerns about the ethics of modifying organisms and about who controls the seeds.
Key points
- Genes are cut out using enzymes.
- A vector carries the gene into the target organism.
- Vectors are usually bacterial plasmids or viruses.
- The gene is transferred at an early stage of development.
- GM bacteria produce human insulin.
- Concerns include effects on wildlife and human health.
Worked examples
Example 1
Describe how a gene is transferred into a plant cell during genetic engineering. [3 marks]
Model answer
Enzymes are used to isolate the required gene from the chromosome of another organism (1 mark). The gene is inserted into a vector, such as a bacterial plasmid or a virus (1 mark). The vector then inserts the gene into the cells of the plant at an early stage of development (1 mark).
Example 2
Give one benefit and one concern about genetically modified crops. [2 marks]
Model answer
Benefit: they can be made resistant to insect attack or herbicides, giving a larger yield of food (1 mark). Concern: they may affect populations of wild flowers and insects, or the effects on human health have not been fully explored (1 mark).
Example 3
Explain why genetic engineering is used to produce human insulin. [2 marks]
Model answer
Bacteria can be genetically modified to contain the human insulin gene (1 mark), and because bacteria reproduce very rapidly, large quantities of human insulin can be produced quickly and cheaply to treat diabetes (1 mark).
Common mistakes
Confusing genetic engineering with selective breeding.
Genetic engineering transfers a gene directly; selective breeding chooses parents over generations.
Forgetting to name a vector.
A plasmid or virus carries the gene, and naming it usually earns a mark.
Giving only benefits when asked to evaluate.
Concerns about wildlife and human health are required.
Saying the gene is inserted into an adult organism.
It must be transferred at an early stage of development so all cells contain it.
Exam tips
- Learn the three steps: isolate with enzymes, insert into vector, transfer to target.
- Name the vector as a plasmid or virus.
- Give both benefits and concerns when evaluating.
- Distinguish clearly from selective breeding.
Key terms
- Genetic engineering
- Transferring genes from one organism to another.
- Vector
- A plasmid or virus used to carry a gene into a cell.
- Plasmid
- A small ring of DNA in a bacterium, used as a vector.
- Genetically modified
- An organism whose genome has been altered by gene transfer.
Related topics
Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.