Final answer:
A very small amount of the competent cells will take up the new plasmid DNA (pDNA) and become resistant to antibiotics such as kanamycin. Since transformation is a low-efficiency process, selection using an antibiotic resistance marker is crucial to identify transformed cells that have taken up the plasmid.
Step-by-step explanation:
A very small amount of the competent cells will actually take in the new pDNA and become kanamycin resistant. Transformation is a procedure with low efficiency, meaning that only a minority of cells are capable of taking up plasmid DNA even after they have been made competent through procedures like heat shock or electroporation. The cells that do incorporate the plasmid can be identified because the plasmid often contains antibiotic resistance genes, which allow transformed cells to survive in an environment containing the respective antibiotic, such as ampicillin or tetracycline. This selection process is essential because not all cells will take up the plasmid, and the presence of an antibiotic in the growth medium ensures that only those bacteria that have been successfully transformed will proliferate.
For example, E. coli cells containing the plasmid vector pBR322 become resistant to ampicillin and tetracycline because the plasmid has genes coding for enzymes that detoxify these antibiotics. Thus, by growing the bacterial culture on a medium containing these antibiotics, only the transformed cells will survive, as they express the resistance provided by the plasmid, while non-transformed cells will not be able to grow. This selective process greatly aids in identifying the cells that have been successfully transformed with the desired plasmid containing the antibiotic resistance gene.