Class 12th Biology 2012 Set1 Outside Delhi Board Paper Solution

Question 12

(a) A recombinant vector with a gene of interest inserted within the gene of α- galactosidase enzyme, is introduced into a bacterium. Explain the method that would help in selection of recombinant colonies from recombinant ones.
(b) Why is this method of selection referred to as “insertional inactivation”?

Answer
(a) Inactivation of antibiotics that requires simultaneous plating on two plates that help in selection of recombinant colonies from non-recombinant ones.
 
(b) This method of selection is referred to as “insertional inactivation” because of the presence of a chromogenic substrate that gives blue coloured colonies if the plasmid in the bacterium does not have an insert.