5.13a - Recombinant DNA

The plasmids are found in bacterial cells. They are a ring of DNA and are small and dont carry many genes

A virus has a protein shell (capsid) and inside there'll be a nucleic acid (DNA or RNA). The virus has no other cellular components (such as cytoplasm nucleus)

Human chromosomes consists of DNA. But we will only look at one gene which codes for the protein insulin which is a hormone that controls blood sugar levels.

1. The restriction enzyme is selected that can cut out the gene responsible for insulin.
2. Once the gene is cut we would cut the plasmid with the same restriction enzyme.
3. This would leave the plasmid with the ring structure broken.
4. The next stage is to introduce the human insulin gene into the cut plasmid (the plasmid is composed of DNA, just like the human gene)
5. The plasmid will then be left with the human gene inserted inside of it.
6. It is then necessary to complete the process by applying a 2nd enzyme (DNA ligase) which will join the DNA
7. This combination of the human gene and plasmid DNA is known as recombinant DNA