In Gene cloning:

Stirred-tank bioreactors have advantages over shake flasks because they

What treatment is given to make a bacterial cell competent to take up $DNA$?

Assertion : The uptake of $DNA$ during transformation is an active,energy-requiring process.
Reason : Transformation occurs in only those bacteria,which possess the enzymatic machinery involved in the active uptake and recombination.

What type of vaccine is the Hepatitis $B$ vaccine?

Plant cells are bombarded with high-velocity micro-particles of ........... coated with $DNA$ in a method known as gene gun.