Genetic engineering involves the extraction of a gene from one organism, or the manufacture of a gene, in order to place it into another organism in which it will be expressed.
Production of insulin
People with type 1 diabetes cannot make insulin and need daily injections. The gene is inserted into bacteria so that large quantities could be manufactured.
- Preparation of insulin gene
- mRNA for human insulin extracted from pancreas cells
- Reverse transcriptase uses mRNA as a template to make single stranded complementary DNA (cDNA) and this is made double stranded by DNA polymerase.
- A single sequence of nucleotides is added to each end of the DNA for sticky ends (GGG)
- Preparation of a vector to carry the human gene into a bacterium
- Plasmid is cut open with a restriction enzyme
- Cut plasmid has a single nucletoides added to each to make sticky ends
- Plasmid and insulin gene are mixed so that sticky ends form base pairs.
- DNA ligase links sugar-phosphate backbones of plasmid and insulin gene.
- Formation of genetically engineered bacteria
- Plasmids are mixed with bacteria in the presence calcium ions (increase porosity)
- Bacteria take up plasmids and multiply to form a clone
- Genetically engineered bacteria transcribe and translate the human gene to make human insulin.
Production of Golden Rice
Provides vitamin A in…