Transforming bacteria to produce human insulin
The following resources have been designed to help you prepare for your visit to GTAC and to study the following Unit 3 AoS1 VCE biology key knowledge areas related to DNA manipulation:
- The use of enzymes to manipulate DNA…..including ligase to join DNA and endonucleases to cut DNA.
- The use of recombinant plasmids as vectors to transform bacterial cells as demonstrated by the production of human insulin.
Historical Perspective of the Discovery of Insulin
The following presentation provides an historical perspective of the discovery of insulin and its importance in treating diabetes.
For further information regarding the mode of action of insulin and its chemical signaling pathway, view the GTAC onilne course Chemical signaling: Insulin or view our Chemical signaling: Insulin video.
Using gene cloning to produce human A chain insulin
Scientists use gene cloning to incorporate a new sequence of DNA into bacteria so the bacteria will replicate the DNA and produce the protein product. They use recombinant DNA technologies to transform bacteria with new sequences of DNA. Some of the molecular tools used in gene cloning are shown in the diagram below.
The following presentation explores how Escherichia coli bacteria are transformed using recombinant plasmid vectors, so they begin to produce human insulin. Click here to download the fillable student logbook notes on gene cloning for insulin production to record information and create a flow chart of gene cloning for insulin production as you watch the video.
STUDENT STUDY NOTE: for examination purposes you will need to study the use of Beta-galactosidase as a reporter gene for insulin A chain and for insulin B chain production in bacteria. In this task we have given the example of GFP as the reporter gene.
Making a model of a recombinant plasmid
In the following activity you will use plasmid maps and restriction enzymes to insert the DNA containing the human insulin A chain and Green Fluorescent Protein (GFP) reporter gene into a model plasmid vector, creating a model recombinant plasmid.
You will then compare and contrast plasmid maps for the original plasmid vector and the recombinant plasmid and consider how these differences can be applied to determine if you have the original or recombinant plasmid in a tube in the lab.
Click here to download the Making a model recombinant plasmid to carry out this activity. If you print this worksheet using a web browser, make sure your paper size setting is A4 and not Letter (as printing in Letter will cut some of the model template off).
Using E. coli bacteria in gene cloning
In the GTAC lab you will genetically modify the bacterium E. coli to produce human insulin A chain polypeptide. Before your visit, learn some useful facts about E. coli.