5.13 Recombinant DNA

Recombinant DNA

Plasmids are find in bacterial cells and are a ring of DNA and are particularly small carrying little DNA.

Viruses have a protein shell called a capsid and inside there would be a Nucleic acid (of which contains either DNA or RNA).


The human chromosome is made of DNA and in our example, we will talk about the gene which codes for the production of the protein, insulin (hormone controlling blood sugar levels).

1. The restriction enzyme would be selected to cut the DNA, leaving us with the gene of insulin separately.
2. Having cut the gene, the plasmid will also be cut with the same restriction enzyme.
3. This leaves the plasmid ring structure broken, the human insulin gene is then inserted into the plasmid.
4. This will leave our plasmid with the human gene inserted and is then necessary to apply ligase enzyme which will join the DNA.
5. This combination of the human gene, and the plasmid is known as recombinant DNA.

Hosting Recombinant DNA 

1. After the recombinant DNA is formed, it is necessary to find a host cell for it. In this instance, we will use the virus to achieve this.
2. We have to remove the nucleic acid from the virus, leaving us with the capsid of the virus alone.
3. The plasmids are taken up by the virus and the virus will act as a vector of the recombinant DNA.
4. It will help us transfer that DNA to our host cell, the virus known as a phage infects bacterial cells, and so the virus is able to attach to the cell membrane of the bacteria and insert the recombinant DNA into our host cell.
5. At the end of this process, we will have a bacteria containing the recombinant DNA including the human DNA for insulin

Credits to daniel lo