Question

In an experiment, recombinant DNA bearing ampicillin-resistance gene is transferred into E.coli cells. The host cells are then cultured on a medium containing ampicillin. The result will be
(a) both transformants and non-transformants cannot survive.
(b) both transformants and non-transformants can survive.
(c) transformants only and not the non-transformants can survive.
(d) transformants cannot survive, but non-transformants can not.

Answer 1

Answer:

The cloning vector requires the presence of a selectable marker, which helps in identifying and eliminating non-transformants and selectively permitting the growth of the transformants. Normally, the genes encoding resistance to antibiotics such as ampicillin, chloramphenicol, tetracycline or kanamycin, etc. are considered useful selectable markers for E. coli. The normal E.coli cells do not carry resistance against any of these antibiotics.

Answer 2

Answer:

If a recombinant DNA bearing gene for resistance to antibiotic ampicillin is transferred to E. coli cells, the host cells become transformed into ampicillin-resistant cells.