Final answer:
Competence in transformation is the ability of cells to uptake external DNA; it is enhanced artificially in laboratories using methods such as chemical treatment or electroporation. Despite these methods, the process of making cells competent is low-yield, necessitating selection for transformed cells.
Step-by-step explanation:
Understanding Competence in Transformation
Competence in the context of transformation refers to the ability of a cell to take up external DNA from its environment. This process is crucial for the genetic modification of bacteria, like E. coli, in biotechnology and research. In nature, some bacteria are naturally competent, meaning they can naturally absorb DNA. However, most bacteria have to be made competent artificially in the laboratory.
Making Cells Competent
The process to make cells competent involves increasing the permeability of the cell membrane so it can take up DNA. This is often achieved through a chemical treatment with calcium chloride, which neutralizes charges on the cell membrane, or by electroporation, where an electric field creates pores in the cell membrane. In a typical laboratory protocol, E. coli cells are incubated with an ice-cold calcium chloride solution and then exposed to a heat shock to prompt the uptake of DNA.
Despite these treatments, transformation remains a low-yield procedure, with only a small percentage of cells becoming competent. Consequently, it is essential to select for those few transformed cells that have successfully incorporated the foreign DNA, as they will express new phenotypic traits.