Question 1

Which of the following best describes the correct aseptic transfer technique when inoculating a nutrient agar slant from a broth culture?

Accepted Answer

Dip a sterile loop into the broth, then drag it in a tight zigzag up the surface of the slant agar.

Question 2

When describing a bacterial colony, which of the following is NOT one of the six characteristics you should record?

Accepted Answer

Colony odor

Question 3

Why is it important to flame the mouth of the test tube before and after transferring bacteria?

Accepted Answer

To prevent contamination of the culture and the environment by killing any microbes present at the tube opening.

Question 4

A student observes a colony with a wavy edge, raised elevation, and yellow pigment. Which terms best describe the margin and elevation of this colony?

Accepted Answer

Undulate margin, raised elevation

Question 5

Which of the following is the correct sequence for aseptic transfer from a stock culture to a nutrient broth?

Accepted Answer

Label tube, sterilize loop, flame tube mouths, transfer sample, flame tube mouths, re-sterilize loop.

Question 6

If a plate has more than 100 colonies of a single type, what should you record for the colony count?

Accepted Answer

TNTC (too numerous to count)

Question 7

Which of the following best explains the purpose of using a straight needle for inoculating a nutrient agar deep?

Accepted Answer

To deliver bacteria to the bottom of the deep agar without disturbing the surface.

Question 8

A student fails to let the inoculating loop cool after flaming and immediately dips it into the stock culture. What is the most likely outcome?

Accepted Answer

The heat will kill most or all of the bacteria in the sample, reducing or preventing growth.

Question 9

Which of the following colony forms is characterized by a root-like appearance?

Accepted Answer

Rhizoid

Question 10

During aseptic transfer, why is it important to avoid touching the loop or needle to any surface after sterilization and before use?

Accepted Answer

To prevent introducing contaminants from the environment onto the sterile instrument.

Question 11

A student describes a colony as 'convex, entire, and white.' Which of the following best matches these terms?

Accepted Answer

The colony is dome-shaped, has a smooth edge, and is white in color.

Question 12

Which of the following best describes the function of aseptic technique in the microbiology lab?

Accepted Answer

It prevents contamination of cultures and protects the experimenter from exposure to microbes.

Question 13

If you observe a colony with a filamentous margin and a flat elevation, which of the following best describes its appearance?

Accepted Answer

The colony has a thread-like edge and a flat profile.

Question 14

Which of the following steps is NOT part of the aseptic transfer protocol?

Accepted Answer

Blowing on the loop to cool it after flaming.

Question 15

A student is transferring bacteria from a stock culture to three different media: broth, slant, and deep. Which instrument should be used for each transfer, respectively?

Accepted Answer

Loop for broth, loop for slant, needle for deep.

Question 16

Which of the following best explains why you should never open a plate with fuzzy, cottony, or web-like growth?

Accepted Answer

Such growth is likely to be fungi, which can release airborne spores and contaminate the lab.

Question 17

A student records the following for a colony: diameter = 2 mm, margin = lobate, elevation = umbonate, pigment = red, number = 15. Which of the following is a correct interpretation of 'umbonate'?

Accepted Answer

The colony has a raised center, resembling a knob.

Question 18

Which of the following equations correctly represents the calculation for the total number of colonies of a specific type on a plate, if you count $$n$$ colonies in each of $$m$$ quadrants?

Accepted Answer

$$Total = n 	imes m$$

Question 19

If you accidentally touch your sterile loop to the bench after flaming, what should you do before proceeding with the transfer?

Accepted Answer

Re-flame the loop to re-sterilize it before use.

Question 20

Which of the following is the best reason for labeling all tubes before starting an aseptic transfer procedure?

Accepted Answer

To prevent confusion and ensure accurate identification of cultures after incubation.

Aseptic Technique and Colony Morphology in Microbiology Lab

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