You Make Two Agar Plates: One Is a Nutrient Agar

Multiple Choice

You make two agar plates: one is a nutrient agar plate (plate A) that contains histidine and penicillin. The other is a glucose salts agar (plate B) that also contains penicillin. You inoculate a sample onto both plates using replica plating technique, incubate the plates, and compare the growth after 48 hours. There are 12 colonies on the nutrient agar plate and 11 colonies on the glucose salts medium. Which of the following statements is INCORRECT?

A) The colony that is missing from plate B is an auxotroph that cannot synthesize histidine.
B) that contains histidine and penicillin. The other is a glucose salts agar (plate
C) The prototrophs are resistant to penicillin but the auxotrophs are sensitive to this antibiotic.
D) that also contains penicillin. You inoculate a sample onto both plates using replica plating technique, incubate the plates, and compare the growth after 48 hours. There are 12 colonies on the nutrient agar plate and 11 colonies on the glucose salts medium. Which of the following statements is INCORRECT?
E) Prototrophs and auxotrophs in this experiment are resistant to penicillin.