You observe a microbiologist examining two plates and notice the pattern of colonies are nearly identical with the exception of a few colonies that are absent on one of them. The plates likely were produced by
A) positive selection culturing.
B) replica plating.
C) pour plating.
D) streak plating.
E) the Ames test.

Question

Quizplus · Accepted Answer

The nearly identical pattern of colonies with only a few absences suggests that the plates were produced by replica plating, where a bacterial sample is transferred from one plate to another using a sterile velvet or membrane. This technique is used to compare different bacterial strains or to test the effect of different growth conditions. Positive selection culturing and pour plating produce different patterns of colonies, while the Ames test is a specific test for mutagenicity, not a general bacterial culture technique. Streak plating is similar to replica plating but may not produce identical patterns of colonies.

You Observe a Microbiologist Examining Two Plates and Notice the Pattern