AQA · GCSE · Biology
Course version: 8461 · Version from Sept 2018
(HT only) Students should be able to describe the main steps in the…
Full specification wording
Genetic engineering: (HT only) Students should be able to describe the main steps in the process of genetic engineering.
Genetic engineering changes an organism’s DNA by inserting a gene from another organism.
Checked against the AQA 8461 specification (opens in a new tab) on .
- Point 12 of 13
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Genetic engineering changes an organism’s DNA by inserting a gene from another organism. The main steps are: identify and isolate the desired gene using enzymes; cut the gene out with a restriction enzyme, which cuts DNA at a specific sequence; use a vector, often a plasmid or a virus, to carry the gene into the target cell; insert the gene into the vector using DNA ligase, forming recombinant DNA; transfer the vector into the target organism’s cells; and identify the cells that have taken up the gene, often using a marker gene. For example, the human insulin gene can be cut out and inserted into a bacterial plasmid, which is then taken up by bacteria that multiply and produce insulin. The gene must be expressed in the target cell to make the desired protein.
What earns the marks
- The desired gene is identified and isolated from the donor organism.
- Restriction enzymes cut the DNA at specific sequences to remove the gene.
- A vector, such as a plasmid or virus, carries the gene into the target cell.
- DNA ligase joins the gene into the vector, forming recombinant DNA.
- The vector is transferred into the target organism’s cells, and cells that have taken up the gene are identified.
- The gene must be expressed so that the target cell makes the desired protein, for example human insulin from bacteria.
Common mistakes and how to put them right
Mixing up the roles of restriction enzymes and DNA ligase.
Put it right: Restriction enzymes cut DNA, while DNA ligase joins DNA, so state each role clearly.
Forgetting the vector; the gene needs a plasmid or virus to carry it into the target cell, so include this step.
Thinking the gene works immediately after insertion.
Put it right: The target cell must express the gene to make the protein, so include expression.
Exam tips
- Write the steps in a logical order: isolate gene → cut with restriction enzyme → insert into vector → transfer to target cell → identify cells → express protein.
- Name the enzymes and the vector to gain credit for specific knowledge.
- Use a named example, such as human insulin produced by bacteria, to show the process in context.
Try the lesson
The start of the Genetic engineering: (HT only) Students should be able to describe the main steps in the process of genetic engineering. lesson, made from checked teaching notes for this specification point.
Have a go first
Which of these is the first main step in the process of genetic engineering?
Listen
Genetic engineering changes an organism’s DNA by inserting a gene from another organism. The main steps are: identify and isolate the desired gene using enzymes; cut the gene out with a restriction enzyme, which cuts DNA at a specific sequence; use a vector, often a plasmid or a virus, to carry the gene into the target cell; insert the gene into the vector using DNA ligase, forming recombinant DNA; transfer the vector into the target organism’s cells; and identify the cells that have taken up the gene, often using a marker gene. For example, the human insulin gene can be cut out and inserted into a bacterial plasmid, which is then taken up by bacteria that multiply and produce insulin. The gene must be expressed in the target cell to make the desired protein. A strong answer earns marks for these points. The desired gene is identified and isolated from the donor organism. Restriction enzymes cut the DNA at specific sequences to remove the gene. A vector, such as a plasmid or virus, carries the gene into the target cell. DNA ligase joins the gene into the vector, forming recombinant DNA. Exam tip: Write the steps in a logical order: isolate gene → cut with restriction enzyme → insert into vector → transfer to target cell → identify cells → express protein.
See it
Put it in order
Put these steps in the order they happen.
- 1. The gene is expressed so the target cell makes the desired protein
- 2. Identify the cells that have taken up the gene, often using a marker gene
- 3. Use a vector, such as a plasmid or virus
- 4. Transfer the vector into the target organism's cells
- 5. Identify and isolate the desired gene
- 6. Cut the gene out with a restriction enzyme
- 7. Insert the gene into the vector using DNA ligase, forming recombinant DNA
Key words
Say what each word means before you turn the card.
Genetic engineering
Try answering aloud or in your head before turning the card.
Restriction enzyme
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Vector
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Recombinant DNA
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See every definition
- Genetic engineering
- Changes an organism's DNA by inserting a gene from another organism.
- Restriction enzyme
- Cuts DNA at a specific sequence to cut the desired gene out.
- Vector
- Often a plasmid or a virus, carries the gene into the target cell.
- Recombinant DNA
- Formed when DNA ligase joins the gene into the vector.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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