InterviewSolution
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InterviewSolution
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Question : Give the various methods to make bacteria a competent host. |
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Answer» Solution :DNA is a hydrophilic molecule, it cannot pass through cell MEMBRANES. In order to force bacteria to take up the plasmids the bacterial cells must be made competent to take up DNA. This is done by following way. Bacterial cell is treated with a specific concentration of a divalent cation such as calcium. Which INCREASES the EFFICIENCY of DNA to enter the bacterium through pores in its cell wall. r-DNA can then be forced into such cells by incubating the cells with recombinant DNA on ice, followed by placing them briefly at `42^(@)C`, and then putting them back on ice. This enables the bacteria to take up the recombinant DNA. Micro-injection : Recombinant DNA is directly injected into the nucleus of an animal cell. Particle Bombardements : Celis are BOMBARDED with high velocity micro particles of gold or tungsten coated with DNA in a method known as biolistics or gene gun. And the last method uses disarmed pathogen vectors, which when allowed to infect the cells transfer the recombinant DNA into the host. |
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