Transformation is the intake of DNA into a cell from the environment.
Bacteria grow rapidly and can easily take up genetic material from their environment.
A plasmid is a small loop of DNA that has been developed to facilitate the cloning process. These plasmids can be easily tracked through antibiotic resistance or fluorescent markers and genes of interest can be easily inserted into the plasmid.
Bacterial transformation is a step in the cloning process, which allows us to genetically modify organisms. For example, cloning gives us the ability to produce large quantities of protein such as insulin.
By suspending bacterial cells into a solution of calcium chloride and heat-shocking, the cell membranes become porous. This allows the plasmid to enter the cell.