Biology – Principles of genetic technology | e-Consult
Principles of genetic technology (1 questions)
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Gene transfer using a plasmid vector in bacterial transformation is a common method for introducing foreign DNA into bacteria. The process involves the following steps:
- Plasmid Preparation: The gene of interest is inserted into a plasmid vector, creating a recombinant plasmid.
- Competent Cells: Bacterial cells are made 'competent', meaning they are able to take up foreign DNA. This is often achieved through chemical treatments or electroporation, which creates temporary pores in the cell membrane.
- Transformation: The recombinant plasmid is mixed with the competent bacterial cells.
- DNA Uptake: The competent cells take up the plasmid DNA.
- Replication and Integration: Once inside the cell, the plasmid replicates along with the bacterial chromosome during cell division. While typically remaining as an extrachromosomal element, the plasmid can sometimes integrate into the bacterial chromosome through homologous recombination. This is less common but can lead to stable expression of the introduced gene.
Role of Competent Cells: Competent cells are essential because they have a mechanism to allow the plasmid DNA to enter the cell. Without competence, the bacterial cell membrane would prevent the plasmid from entering.