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If the chemical X-gal is added to nutrient agar, lactose fermenting colonies turn blue, while non-fermenting colonies appear white. What sort of medium is X-gal agar?

User JP Illanes
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Answer:

C. Differential.

Step-by-step explanation:

Differential media are bacteriological growth media that contain specific ingredients to allow one to distinguish selected species or categories of bacteria by visual observation. Examples of differential media includes:

Blood agar (used in strep tests) contains bovine heart blood that becomes transparent in the presence of β-hemolytic organisms such as Streptococcus pyogenes and Staphylococcus aureus.

Eosin methylene blue is differential for lactose fermentation.

Streptococcuseosin methylene blue (EMB), which is differential for lactose and sucrose fermentation.

User HaveF
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