Question

If you forgot to add x-gal to the agar selection medium, how would the colonies that grow differ phenotypically from the ones that grow in plates with x-gal? briefly explain your answer

Answer 1

If X-gal is not added to the agar selection medium all of the colonies would be white.

X-gal is an organic compound used to test the presence of an enzyme, β-galactosidase. X-gal is colourless, but in the presence of β-galactosidase, it becomes blue because of the cleavage of the β-glycosidic bond inside its structure.