A plasmid contains a multiple cloning site inside the coding region of the lacZ gene and also contains an ampicillin resistance gene at a separate locus.When cells are transformed with a successfully recombinant plasmid containing a piece of DNA cloned into the multiple cloning site,what color will the colonies be when grown on an agar plate containing ampicillin and X- gal?
A)blue
B)clear
C)white
D)colonies will not grow
E)green

Question

Quizplus · Accepted Answer

When grown on agar plates containing X-gal, colonies with a functional lacZ gene will appear blue due to the hydrolysis of X-gal by β-galactosidase. However, if the lacZ gene is interrupted by cloning in the multiple cloning site, the colonies will not produce functional β-galactosidase and will not hydrolyze X-gal, resulting in white colonies. The presence of the ampicillin resistance gene in the plasmid allows only transformed cells with the plasmid to survive on the agar plates containing ampicillin.

A Plasmid Contains a Multiple Cloning Site Inside the Coding