By Eileen, Daniel and Andrew Genetic engineering By Eileen, Daniel and Andrew

Contents Use of restriction enzymes & ligase How plasmids and viruses act as vectors How human insulin can be produced by genetically modified bacteria Potential of genetically modified plants Definition of ‘transgenic’

Restriction enzymes & ligase Restriction enzymes basically cuts the DNA apart at a specific location. DNA Ligase joins stands of DNA that have been cut apart back together. Restriction enzymes and ligase are the tools used in genetic engineering.

How plasmids and viruses act as vectors A vector is a carrier for genes Viruses typically contain either DNA or RNA Plasmids are rings of DNA normally found in bacteria A specific gene can be introduced into the plasmid. The plasmid is cut by restriction enzymes. The human gene is stuck onto the plasmid through ligase enzymes The ‘human gene’ can be taken from the chromosomes of an animal cell. The nucleic acid of a virus is removed the modified plasmid is insert into the protein shell of the virus. This virus then infects a bacteria cell by injecting the modified plasmid into the bacteria cell. The infected bacteria cell is now hosting the recombinant DNA.

Production and genetic modification of human insulin The infected bacteria cells are placed into a fermenter This produces large amounts of human insulin As seen on the previous slide, the recombinant DNA injected into the bacteria cells caused them to produce human insulin instead of alcohol. When placed into a fermenter, producing large amounts of insulin is now possible.

Potential of genetically modified plants Take genes from organisms with a natural resistance Put genes into dna of affected plant The example we used here is maize. Crop yield loss of up to 20% is caused by the European cork borer. (insect larvae) A type of bacteria called bacillus thuringiensis (BT) has a gene which produces BT toxin when activated. This gene is extracted from their plasmid and coated onto gold particles which are then fired into the plant cells of maize. As the plant now have this gene, they are able to produce bt toxin which kills the larvae.

Definition of transgenic Transfer of genetic material from one species to another.