In a bioreactor,through which system can a small volume of culture be withdrawn periodically?

Describe the role of $CaCl_2$ in the preparation of competent cells.

The entry of $t-DNA$ into plants is associated with which of the following?

How can a recombinant protein be obtained?

Taking examples under each category,discuss upstream and downstream processing.

From the following tools/techniques of genetic engineering,identify those which are required for cloning a bacterial gene in animal cells and choose the correct option:
$I$. Endonuclease $II$. Ligase
$III$. $A. tumefaciens$ $IV$. Microinjection
$V$. Gene gun $VI$. Lysozyme
$VII$. Cellulase $VIII$. Electrophoresis