After we have grown genes to a necessarily large quantity, we insert the genes into plasmid vectors, which are circular DNA molecules used to transfer to cells our foreign genes, using a chemical reaction called ligation which ‘glues’ two DNA molecules at their ends to make them into one. After this, we then transform the cells to be worked on into the genetically engineered ones by transferring the modified vectors to the organism under certain intentional conditions such as preparing cells by chilling in a CaCl2 solution then briefly heat shock cells with them incubated on ice.1 With the cells finely genetically altered, we can observe the presence of various functionalities expected from our assumptions which will be discussed in specific details in the following pages.

When cells are transformed, the plasmid we transferred into them will replicate along with the cells’ own DNA, allowing the gene expression to occur. Gene expression is a series of reactions to produce proteins (molecules with different functions according to their structures) from genes. It goes through the process known as ‘transcription’, converting DNA’s into mRNA (messenger ribonucleic acid) molecules, following by the one called ‘translation’, converting mRNA into polypeptide chains which are ultimately folded into proteins.

References

1 Large-volume transformation with high-throughput efficiency chemically competent cells. Focus 20:2 (1998)