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While performing a quadrant streak (also called the streak plate method) with a bacterial sample, the purpose of sterilizing the loop between each quadrant is:

The presence of more than one kind of colony on an agar plate indicates that the original sample used to streak the plate consists of a mix of different types of bacteria.

The following picture taken from a rotting potato? What conclusions can you make from the clear zones seen on the plate?

If you begin with 10 bacteria and the bacteria divide exponentially, how many bacteria will you have at the end of 2 hours?  The generation time of the bacteria is 20 minutes.

You are determining the purity of water sample by plating a small volume on a media that selectively allows the growth of coliforms.  A colony that would grow on this media would appear ——— color upon gram staining.

A patient went to the ER with severe wound infection of the leg after swimming in a lake.  Gram staining of a sample from his wound showed the following results.  Based on this picture, the bacteria isolated from the wound can be described as which of the following?

  —————- cells have a thin layer of peptidoglycan, while ————— cells have a thick layer of peptidoglycan in their cell walls.

In an experiment, 1 mL of a bacterial sample was serially diluted with 9 mL of water.  1 mL of each dilution was plated on nutrient agar and incubated at an appropriate temperature to visualize colonies.   Based on the following scheme of dilution, which answer best describes the bacterial concentration ( CFU/mL) in the original sample? 

Which of the following statements about the organism shown in the picture is true?  

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