Description of Competent Cells
Competence is a special physiological state of a bacterial cell in which a cell can take up exogenous DNA from the surrounding environment and is not easily decomposed by a restriction endonuclease inside the cell.
Using specific techniques in a laboratory setting, bacterial cells can be transformed into the state of competence for molecular biology applications. For example, the electrical method takes advantage of the low-permeability of bacterial cells in their rapidly-growing phase of their life cycle. By shocking bacteria at this stage with high-intensity transient electric field, the negatively-charged DNA passes through the cell membrane and enters the cell.
DIY Protocol for Generating Electro-Competent Cells
Reagents
- Bacterial cells
- LB medium
- LB agar plates
- Sterile ddH2O
- Glycerol (10%)
Equipment
- Shaker
- Stationary and shaking incubator
- Refrigerated centrifuge
- Ice bucket with ice and liquid nitrogen
- Tubes (centrifuge, test, Eppendorf)
