Lab 1-cultures and aseptic technique

Question 1

Most microbes are easily cultured on laboratory media. T / F

Answer 1

False

Question 2

2. Microbial growth media must include a source of micronutrients. T / F

Answer 2

True

Question 3

Autoclaving is a common method of sterilizing growth media.

Answer 3

True

Question 4

A flamed wire loop must glow red to be considered sterile.

Answer 4

False

Question 5

You should always set tube caps, test tubes, and culture plates securely on the benchtop when
performing inoculations and transfers.

Answer 5

False

Question 6

Based on the recipe below for the preparation of M9 medium, is M9 medium a chemically
defined medium or a complex (undefined) medium?

Answer 6

defined medium

Question 7

What is agar or agarose used for in microbial growth medium?

Answer 7

To make the growth medium solidify.

Question 8

Which of the following is NOT a component of most common microbial growth media.

Answer 8

Antibiotics such as rifampin

Question 9

Sterile technique is also commonly referred to as?

Answer 9

Aseptic technique

Question 10

For inoculating a nutrient broth, what is the purpose of flaming the tube mouth

Answer 10

• To incinerate microbes on the tube mouth.
• To create an updraft to prevent airborne contamination

Question 11

For inoculating a nutrient broth, What has presumably been
performed prior to step 1 as shown?

Answer 11

The inoculating loop has been properly sterilized by flaming and allowed to cool for 30 - 60 seconds

Question 12

When practicing sterile technique with microbial cultures which of the following is NOT a major concern.

Answer 12

Make sure you can see visible bacterial culture growth on your inoculating loop prior to completing the inoculation.

Question 13

Which of the following best describes how to inoculate a nutrient agar plate?

Answer 13

Hold both plate and lid in one hand, with the lid tipped up and gently trace the inoculating loop in a serpentine pattern across the surface of the agar.

Question 14

After you have inoculated an agar plate how should it be incubated?

Answer 14

Labeled on the bottom of the plate with the lid securely fitted and the plate up-side-down

Question 15

Which of the following is NOT a recommendation for the proper, safe use of a Bunsen burner?

Answer 15

All of these are proper guidelines for Bunsen burner operation.

• Avoid wearing loose-fitting clothing.
• Check the burner and the tubing for cracks or leaks prior to operating.
• Adjust the flame to have a hot blue inner cone and a cooler outer corona.
• If the burner fails to light in 5 seconds, turn off the gas valve and wait 15 seconds before attempting to light again.

Question 16

The four species of bacteria used to practice sterile technique and inoculations in exercise
1-3 were?

Answer 16

Micrococcus luteus, Staphylococcus epidermidis, Escherichia coli, Bacillus subtilis

Question 17

Which of the following is NOT a growth medium we learned to inoculate in lab?

Answer 17

Sterile saline

Question 18

The 0.3 % beef extract used in the preparation of nutrient agar necessitates that nutrient agar
be defined as what kind of medium?

Answer 18

Complex

Question 19

Any disposable item used to work with microbial cultures should be disposed of by
which of the following methods?

Answer 19

Placed in the orange biohazard bags to be autoclaved.

Question 20

Which of the following sources did we NOT test for the presence of microbes?

Answer 20

Human blood