Biology - Biotechnology - Principles and Processes Question with Solution | TestHub

DNA is a hydrophilic molecule and cannot pass through cell membranes easily.

To make the bacterial cells competent to take up recombinant DNA, they are treated with a specific concentration of a divalent cation, such as calcium ($C{a}^{2+}$).

This treatment increases the efficiency with which DNA enters the bacterium through pores in its cell wall.

Therefore, the transfer of rDNA into the cloning host bacterium is assisted by divalent $C{a}^{2+}$.

Answer: divalent Ca(++)