Making cells competent is essential for biotechnology experiments because it enables host cell or bacteria to take up DNA.

DNA being a hydrophilic molecule, cannot pass through cell membranes, hence the cells should be made competent to accept the DNA molecules .

The two ways by which this can be achieved is:

1. Chemical method : By treating the bacterial cells with divalent cation such as Calcium, makes them competent and helps them to take up DNA through the pores in the cell wall.

2. Physical method: in this, the rDNA is directly injected into the nucleus of an animal cell by microinjection method.

In plants, cells are bombarded with high velocity micro particles of gold or tungsten coated with DNA called as Biolistics or Gene gun method.