NEETZoologyBiotechnology - Principles and Processes
Arrange the following steps in the correct chronological order to make a bacterial cell competent and force it to take up a recombinant plasmid: A. Placing the cells briefly at 42^ C (heat shock) B. Incubating the cells with recombinant DNA on ice C. Treating the cells with a specific concentration of a divalent cation (e.g., calcium) D. Putting the cells back on ice Choose the correct sequence from the options given
Options
- AC B A D
- BC A B D
- CB C A D
- DC B D A
Correct answer
A. C B A D
Step-by-step solution
To force bacteria to take up a plasmid, the bacterial cells must first be made competent. This is done by treating them with a specific concentration of a divalent cation, such as calcium, which increases the efficiency with which DNA enters the bacterium through pores in its cell wall (Step C). Recombinant DNA can then be forced into such cells by incubating the cells with recombinant DNA on ice (Step B). This is followed by placing them briefly at 42^ C for a heat shock (Step A). Finally, the cells are put back o