(i) Explain how to find whether an E.coli bacterium has transformed

(i) Explain how to find whether an E.coli bacterium has transformed or not, when a recombinant DNA bearing ampicillin-resistance gene is transferred into it.
(ii) What does the ampicillin-resistant gene act as, in the above case?

(i) The recombinant/transformant can be selected out from the non-recombinants/ non-transformants by plating the transformants on ampicilin-containing medium. The transformants will grow in it, while the non-transformants will not grow.
(ii) It acts as a selectable marker.