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Genetic engineering and transgenic organisms
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Scientists can cut a gene from one organism and insert it into another, even of a different species.
Cutting and joining DNA
Restriction enzymes cut DNA at specific sequences of bases.
The same restriction enzyme is used to cut the gene out and to cut open a plasmid, so the ends match.
Ligase enzymes join the pieces of DNA together. The result is recombinant DNA.
The same restriction enzyme is used to cut the gene out and to cut open a plasmid, so the ends match.
Ligase enzymes join the pieces of DNA together. The result is recombinant DNA.
Vectors and insulin
A vector carries the recombinant DNA into another cell. Plasmids and viruses can act as vectors.
Human insulin: the human insulin gene is inserted into a bacterial plasmid, which is taken up by bacteria. The bacteria are grown in large fermenters, where they make large amounts of human insulin, which is extracted and purified.
Human insulin: the human insulin gene is inserted into a bacterial plasmid, which is taken up by bacteria. The bacteria are grown in large fermenters, where they make large amounts of human insulin, which is extracted and purified.
GM plants and transgenic organisms
Genetically modified plants can improve food production, for example crops that are resistant to insect pests or to herbicides, or that give higher yields.
A transgenic organism contains genetic material transferred from another species.
A transgenic organism contains genetic material transferred from another species.
Why is the same restriction enzyme used to cut both the human DNA and the plasmid?
- Each restriction enzyme cuts at a specific base sequence.
- Using the same enzyme gives matching ends.
- Ligase can then join the gene into the plasmid.
Answer: So the cut ends match and can be joined by ligase.
Restriction enzymes cut DNA at specific sites; ligase joins DNA. Plasmids and viruses act as vectors carrying recombinant DNA into cells. GM bacteria in fermenters make human insulin. GM crops improve food production. Transgenic organisms contain genes from another species.
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