Lab 3, Chapter 11

To study growth characteristics, pathogenicity, metabolism, antibiotic susceptibility or othe characteristics, requires:

A. A growth medium

B. Agar

C. Broth

D. Pure Culture

A Pure culture contains:

A. Bacteria

B. Virus

C. isolated microbes

D. A single type of microbe

Because bacteria are too small to separate directly without sophisticated micromanipulation equipment, of separation are used.

A. Scientific Methods

B. Sterile Methods

C. Microbiology Methods

D. Indirect Methods

In the 1870's attempted to obtain pure cultures by performing serial dilutions until each of the containers theoretically contained one bacterium.

A. Joseph Lister

B. Paul Ehrlich

C. Ronald Ross

D. Robert Koch

In 1880 prepared solid media

A. Joseph Lister

B. Paul Ehrlich

C. Ronald Ross

D. Robert Koch

Currently, three dilution methods are commonly used for isolating bacteria:

A. Streak Plate, Spread Plate, Pour Plate

B. Hot Plate, Cold Plate. Warm Plate

C. Red Plate, Blue Plate, Green Plate

D. Acid Plate, Base Plate, Dilute Plate

The and are quantitative techniques to determine the number of bacteria in a sample.

A. Streak Plate and Spread Plate

B. Streak Plate a Pour Plate

C. Spread Plate and Pour Plate

The technique, a loop is used to streak the mixed sample many times over the surface of a solid culture medium in a Petri dish.

A. Streak Plate

B. Spread Plate

C. Pour Plate

In the technique, a small amount of a previously diluted specimen is spread over the surface of a solid medium using a spreading rod.

A. Streak Plate

B. Spread Plate

C. Pour Plate

In the technique, a small amount of diluted sample is mixed with melted agar and poured into empty, sterile Petri dishes.

A. Streak Plate

B. Spread Plate

C. Pour Plate

When reporting results for the streak plate method (colony descriptions), which of the following IS NOT reported?

  1. Diameter
  2. Appearance
  3. Margin
  4. Elevation
  5. Color
  6. pH

Which of the following is TRUE in regards to inoculating a Petri plate?

  1. Lift one edge of the corner while the plate rests on the table
  2. Lift the entire lid while the plate rests on the table
  3. Take the lid off and place it face down on the table, as well as the plate

For the pour plate technique, what happens to the bacteria prior to pouring them into Petri dishes?

  1. We expose them to flame prior to placing them in the incubator
  2. We run a series of tests to determine their pH
  3. The bacteria are diluted through a series of tubes containing 19 ml of melted nutrient agar

In regards to Ch.11 “Isolation of Bacteria by Dilution Techniques,” which of the following is NOT an objective?

  1. Isolate bacteria by using the streak plate and pour plate techniques
  2. Use various staining techniques in order to isolate bacteria
  3. Prepare and maintain a pure culture

Which of the following correctly depicts the streak plate technique for pure culture isolation of bacteria, as depicted in our lab manual?

A

B

C

Which of the following depicts the CORRECT way to mix the inoculum in a tube?

A

B

C

What is contamination?

  1. The presence of unwanted microorganisms
  2. The absence of unwanted microorganisms
  3. Using a mixed culture to reach a pure culture

Which of the following is NOT one of the most commonly used dilution methods for isolating bacteria?

  1. Streak plate method
  2. Spread plate
  3. Pour plate
  4. A complex medium consisting of peptones

Which of the following is the MOST COMMON isolation technique used today?

  1. Streak plate
  2. Pour plate
  3. Spread plate

Chapter 12

True/False

One of the major limitations of dilution techniques used to isolate bacteria is that organisms present in limited amounts may be diluted out on plates filled with dominant bacteria. True

If bacterium B is heat-resistant, the specimen could be heated after isolation. False

Dyes such as phenol red, eosin, or methylene blue are sometimes included in differential media. True

What methods are used to isolate particular organisms?

  1. Selective media
  2. Enrichment media
  3. Differential media
  4. All of the above
  5. (A and C)
  6. None of the above

What is selective media?

  1. Contain various nutrients that allow the investigator to distinguish one bacterium from another by how they metabolize or change the media with a waste product
  2. Media that contain nutrients that enhance growth of desired bacteria.
  3. Contain chemicals that prevent the growth of unwanted bacteria without inhibiting the growth of the desired organism.

What is enrichment media?

  1. Contain chemicals that prevent the growth of unwanted bacteria without inhibiting the growth of the desired organism.
  2. Media that contain nutrients that enhance growth of desired bacteria.
  3. Contain various nutrients that allow the investigator to distinguish one bacterium from another by how they metabolize or change the media with a waste product

What is differential media?

  1. Contain various nutrients that allow the investigator to distinguish one bacterium from another by how they metabolize or change the media with a waste product.
  2. Media that contain nutrients that enhance growth of desired bacteria.
  3. Contain chemicals that prevent the growth of unwanted bacteria without inhibiting the growth of the desired organism.

Why is special media testing performed?

A. It helps isolate organisms found in the minority

B. Various enrichment and selective culturing methods are available that enhance the growth of certain organisms.

C. Various enrichment and selective culturing methods are available that inhibit the growth of certain organisms.

D. All of the above

Selective media contains chemicals that prevent the growth of unwanted bacteria without inhibiting the growth of the desired organism.

True

Fale

Enrichment media contains chemicals that inhibit the growth of specific desired bacteria.

True

False

Enrichment media is typically

A. Solid and bacteria in addition to the desired one one will grow.

B. Solid and no bacteria other than the desired one will grow.

C. Liquid and bacteria in addition to the desired one will grow.

D. Liquid and no bacteria other than the desired one will grown.

With special media testing, how does one incubate the plate?

A. Inverted at 0 degrees Celcius

B. Inverted at 35 degrees Celcius

C. Right side up at 0 degrees Celcius

D. Right side up at 35 degrees Celcius

Using differential media, dyes such as phenol red, eosin, or methylene blue are included to produce a color change in the medium or colonies. What part of the bacteria reacts to this?

A. Products of bacterial metabolism

B. Bacterial cell walls
C. Products of bacteria organelles
D. Proteins in the bacteria

Which techniques are used in special media testing?

A. Streak plate procedure
B. Gram staining
C. Aseptic techniques
D. All of the above

Chapter 22

Extreme ______is widely used to control the growth of microbes.

  1. temperature
  2. moisture
  3. light
  4. all of the above

Generally, if _____ is applied, microbes are killed; if _____ temperatures are used, microbial growth is inhibited.

  1. cold, hot
  2. heat, cold
  3. moisture, extreme
  4. both A & C

Psychrophilic refers to optimal growth ranges about ______.

  1. 0 degrees celcius to 20 degrees celcius
  2. 20 degrees celcius to 30 degrees celcius
  3. 25 degrees celcius to 40 degrees celcius
  4. 45 degrees celcius to 65 degrees celcius
  5. about 80 degrees celcius or higher

Psychrotrophic refers to optimal growth ranges about ______.

  1. 0 degrees celcius to 20 degrees celcius
  2. 20 degrees celcius to 30 degrees celcius
  3. 25 degrees celcius to 40 degrees celcius
  4. 45 degrees celcius to 65 degrees celcius
  5. about 80 degrees celcius or higher

Mesophilic refers to optimal growth ranges about ______.

  1. 0 degrees celcius to 20 degrees celcius
  2. 20 degrees celcius to 30 degrees celcius
  3. 25 degrees celcius to 40 degrees celcius
  4. 45 degrees celcius to 65 degrees celcius
  5. about 80 degrees celcius or higher

Thermophilic refers to optimal growth ranges about ______.

  1. 0 degrees celcius to 20 degrees celcius
  2. 20 degrees celcius to 30 degrees celcius
  3. 25 degrees celcius to 40 degrees celcius
  4. 45 degrees celcius to 65 degrees celcius
  5. about 80 degrees celcius or higher

Hyperthermophilic refers to optimal growth ranges about ______.

  1. 0 degrees celcius to 20 degrees celcius
  2. 20 degrees celcius to 30 degrees celcius
  3. 25 degrees celcius to 40 degrees celcius
  4. 45 degrees celcius to 65 degrees celcius
  5. about 80 degrees celcius or higher

Heat such as that in hot-air ovens or incineration are what type of heating?

  1. Moist
  2. Dry
  3. Extreme
  4. None of the above

Heat methods such as pasteurization, boiling, and autoclaving are what type of heating?

  1. Moist
  2. Dry
  3. Extreme
  4. None of the above

The most effective method of moist heat sterilization that involves steam under pressure is known as ______.

  1. Boiling
  2. Autoclaving
  3. Incineration
  4. Baking

Match the rate of growth to the correct temperature:

A) Hyperthermophilic

B) Psychrotropic

C) Thermophilic

D) Psychrophilic

E) Mesophilic

Temperature in Degrees (in Celsius)
0-20 (D)
20-30 (B)
25-40 (E)
45-65 (C)
80 or higher (A)

Overall, bacteria are more ______resistant that most other forms of life.

A) Heat

B) Cold

Heat sensitivity of organism can be affected by what?

A) Container size and cell density

B) Container size, cell density, and moisture content

C) Container size, cell density, moisture content, and pH

D) Container size, cell density, moisture content, pH, and medium composition

Dry heat denatures enzymes, dehydrates microbes, and kills by oxidation effects.

A) True

B) False

Moist heat methods include which of the following:

A) Pasteurization

B) Boiling

C) Autoclaving

D) All of the above

A psychrophilic optimal growth range is ______?

  1. 45° C - 65° C B. 20° C - 30° C. 25° C - 40° C D. 0° C - 20° C

A thermophilic growth range is between 45° C - 65° C.

True False

Bacteria is NOT more heat resistant than most others forms of life.

True False

Pasteurization, boiling and autoclaving are all examples of ______

  1. Dry Heat B. Moist Heat C. Thermophilic D. Procedure Heat

Hot air ovens and incineration are which type of heat?

  1. Dry Heat B. Moist Heat C. Thermophilic D. Procedure Heat

Which one of the following is NOT accomplished with Dry Heat?

  1. Denatures Enzymes B. Dehydrated Microbes C. Oxidation D. Composition

Autoclaving is the most effective method of moist heat sterilization.

True False

Boiling for 2 minutes will kill vegetative bacteria

True False

Which is appropriate for Pasteurization?

  1. 63° C for 30 min B. 72° C for 15 seconds C. 59 ° C for 20 minutes D. Both A & B

Heat sensitivity can be affected by

  1. container size B. cell density C. moisture content D. All of the above

Chapter 24

Chemical agents used on inanimate objects to lower the level of microbes on their surfaces are

A Antiseptics

B Bactericidal

C Disinfectants

Chemicals that cause temporary inhibition of growth are bacteriostatic agents

A True

B False

Chemicals used on living tissue to decrease the number of microbes are

A Antiseptics

B. Disinfectants

C Bactericidal

D. All of the above

E. Both A and C only

Antimicrobial agents must be matched to a specific organisms and environmental conditions.

A False

B True

Variables to consider in selecting an antimicrobial agent include

A pH

B solubility

C toxicity

D all of the above

What is an important criteria in evaluating the effectiveness of antimicrobial agents

A the concentration

B the pH of the solution

C length of contact

D. All of the above

E both A and C

Bacteriostatic agents cause temporary inhibition of growth

A True

B False

How many strains are used for the use-dilution test for most purposes?

A 1

B 4

C 3

D None of the above

What type of technique is used for the use-dilution test

A Sterile

B Aseptic

C Clean

What is a disinfectant?

A. chemical objects used on inanimate objects to lower the level of microbes on their surfaces

B. chemical objects used on objects to raise the level of microbes on surfaces

C. chemical objects used to show microbes on surfaces

D. chemical objects used to collect microbes on surfaces

What are the intervals of time used to inoculate bacteria on a Petri dish?

  1. 5,10,15,and then 20 minutes
  2. 2,4,6,8, and then 10 minutes
  3. 1, 3,5,7 and then 9 minutes
  4. 2.5, 5, 10, and then 20 minutes

Disinfectants and antiseptics affect bacteria in many ways. Those that result in bacterial death are called :

  1. bactericidal fluids
  2. bactericidal waste
  3. bactericidal sanitizers
  4. bactericidal agents

Antimicrobials causing temporary inhibition of growth are:

  1. bacteriostatic agents
  2. bactericidal agents
  3. bacteriostatic chemicals
  4. bactericidal chemicals

True or false. The standard method for measuring the effectiveness of a chemical agent is the American Official Analytical Chemist’s use-dilution test. True

True or false. The use-dilution test is limited to bactericidal compounds and cannot be used to evaluate bacteriostatic compounds. True

Wide varieties of chemicals called agents are available for controlling the growth of microbes.

  1. Antimicrobial
  2. Disinfectants
  3. Antiseptics
  4. None of the above

What are the variables to consider in selecting an antimicrobial agent?

  1. pH
  2. Solubility
  3. Toxicity
  4. Organic material present
  5. Cost
  6. All of the above

The effectiveness of disinfectant can be determined by the amount of resulting growth. T

In evaluating the effectiveness of antimicrobial agents, the concentration, length of contrast, and whether it is lethal (-cidal) or inhibiting (-static) are the important criteria. T

Enumeration

When a doctor takes a swab from an infected wound:

  1. It is to find out which organisms are present so he can select the proper antibiotic
  2. There will usually be more than one organism present
  3. Pure cultures need to be made to identify the organism(s)
  4. All of the above

True or false - E. coli forms white colonies:

  1. True
  2. False

If three organisms each grew different color colonies on a plate, but all were Gram negative:

  1. If you only did a Gram stain each organism would color differently because they are different organisms
  2. If you only did a Gram stain it would look as if there were only one organism present
  3. It is impossible to isolate each organism
  4. The organisms are not transferrable to a petri dish for further examination

When inoculating cultures with a loop:

  1. Poke the agar several times with the loop to create air holes
  2. Make sure the loop is still red-hot when placing it in the agar
  3. Straighten the loop so that it forms a needle-like point and it is no longer round at the end
  4. Sterilize the loop with a flame between samples to avoid unwanted contamination

If your colonies overlap after streaking to isolate the organisms with a zigzag like motion in a petri dish:

  1. You have created a culture that is difficult to examine the variations in organisms
  2. You failed because perhaps there were too many organisms on the first quadrant
  3. You failed because you dragged to long across quadrants of the petri dish
  4. You failed because your zigzags were too narrow and did not cover enough surface area
  5. All of the above

True or false: When incubating the cultures, you should place them right side up so that condensation is able to collect and provide water to the organisms

  1. True
  2. False

True or false: Cultures should be placed in the incubator upside-down so that removing it from the incubator is easier and prevents accidental removal of the lid

  1. True
  2. False

One way to know if your organism isolation techniques were successful is:

  1. There are multiple colors in each tube indicating multiple organisms
  2. There is only one color in each tube
  3. The tube has turned black
  4. One can never know if their isolation efforts were successful

Who is called when there is an unusual amount of people that come in with the same illness?

  1. The Center for Disease Control (CDC)
  2. The Hospital
  3. Urgent Care

What does the CDC do when there is an unusual amount of people that come in with the same illness?

  1. Interview the patients to find out if all the patients went to the same location right before they got sick.
  2. Count the number of patients in the hospital.
  3. Examine Nursing techniques.

What is the measurement of how many living and dead organisms per ml are in the sample?

  1. Cultures
  2. Turbidity (cloudiness)
  3. Community

What is the name of the machine that measures turbidity?

  1. Microscope
  2. Spectrophotometer
  3. Incubator

Using a spectrophotometer to measure turbidity is a(n) ______estimate of cell density.

  1. Direct
  2. Indirect

What does the indirect method of enumeration of bacteria rely on?

  1. The color of the sample
  2. The number of the bacteria in the sample
  3. The cloudiness of the sample

What is the Standard Plate Count (SPC)?

  1. The number of colonies that grow on a plate.
  2. The Direct Method of enumeration of bacteria
  3. All of the above.

Before a standard plate count can be performed what must first happen?

  1. A serial dilution
  2. Staining
  3. Culture count

Transmission and absorbance are:

  1. Directly related
  2. Inversely related
  3. Neither

Cuvettes are made of:

  1. Plastic
  2. Optically pure glass
  3. Cork
  4. Plates

To make a standard plate count, how do you make a plate that has the colonies that are within our ability to count?

A. We need to have a plate that does not have too many colonies to count.

B. Dilute the original plate and do a series of dilutions.

C. Let the bacteria grow for a few days and see how many grew.

D. All of the above

The number of colonies that are within our ability to count are

A. 10-300

B. 30-300

C. 100-300

D. 300-500

If there are more than 300, some colonies may overgrow on other colonies and the count is not accurate. If there are less than 30 colonies, there are not enough to count.

A. True

B. False

Which of the below four plates can be used to count colonies?

A. Bottle B, first plate = 1:10,000  800 colonies

B. Bottle B, second plate = 1:100,000  200 colonies

C. Bottle C, first plate = 1:1,000,000  20 colonies

D. Bottle C, second plate = 1:10,000,000  10 colonies

The formula for Concentration is Colony numbers x Dilution Factor= Concentration

A. True

B. False

How do you write the solution for concentration?

A. Write the number and box it

B. Convert to scientific notation

C. Convert to scientific notation and write units (org/ml)

What are the proper dilution sequence when making a dilution series?

A. 1:10-- 1:100-- 1:1000

B. 1:100-- 1:1000-- 1:10,000