Final answer:
The result of growing an LB agar with ampicillin and a plasmid containing the lac operon (without lactose) would be the formation of white colonies.
Step-by-step explanation:
The result of growing an LB agar with ampicillin and a plasmid containing the lac operon (without lactose) would be the formation of white colonies.
The lac operon is a group of genes that are involved in lactose metabolism. When there is no lactose present, the lac operon is repressed, meaning that the lacZ gene, which produces the enzyme to metabolize lactose, is not active.
Therefore, in the presence of ampicillin and without lactose, the bacteria carrying the plasmid would produce white colonies because they have a disrupted lacZ gene and cannot metabolize X-gal, a substance that changes color when exposed to the enzyme produced by the lacZ gene.