BCS 200 Lab Practical

In a serial dilution, the final dilution factor performed was 1:100,000. After 48 hours incubation @ 37oC there were 190 colonies counted on the plate. What was the concentration of bacteria in the original undiluted sample?

19,000,000 cfu/mL

In this image of the objective lenses on a compound light microscope the lens on the far left would allow you to view a specimen at?

400x total magnification

How many different types of waste disposal containers and/or areas are students responsible for using in the microbiology lab, including the area next to the autoclave specifically designated for sterilization of glass culture tubes?

5

What type of staining needs to be done on sputum cultures to identify the presence of Mycobacterium?

Acid-Fast stain

Lysis of red blood cells occurs but the iron in the RBC is not consumed as a food source

Alpha Hemolysis (B section)

The appearnce of a greenish color with bacterial growth on blood agar

Alpha Hemolysis (B section)

What type of spores are shown here?

Ascospores

A fundemental technique important in the laboratory and used by Microbiologists for a variety of procedures such as, transferring cultures, inoculating media and isolation of pure cultures is known as?

Aseptic technique

Metal inoculating loops and needles are sterilized before and after use in a desktop incinerator to prevent introduction of unwanted organisms. Agar plates are held in a manner that minimizes the exposure of the surface to the environment. These are common practices that are observed while using proper_______________.

Aseptic technique

This is the environmental sample taken by a student from a cell phone. The sample was plated on Nutrient agar and allowed to incubate for 48 hours @ 37oC. After observing the growth on this plate the most accurate statement would be?

Based on colony morphology, coloring and size there are at least 4 different species of bacteria that were living in the same general location on the cell phone

In this type of hemolysis a clear zone is left behind in the agar

Beta Hemolysis (A section)

This is the complete lysis of red blood cells on blood agar where all of the contents of the cell were consumed as a nutritional source

Beta Hemolysis (A section)

3. A chemical that you are about to use has the following symbols on its label. What do they mean? Health Hazard

Carcinogen Mutagenicity Reproductive Toxicity Respiratory Sensitizer Target Organ Toxicity Aspiration Toxicity

What type of spores are shown here?

Conidiospores

Differential media is a type of specialty media which?

Contain specific dyes that cause a color change as different bacteria grow and produce waste products.

Which is the the correct order of chemicals in the Gram's stain procedure?

Crystal Violet, Iodine, Decolorizer, Safranin

What is known as the differential step in the Gram's stain procedure and why?

Decolorizer is the differential step because it is during this step that the gram negative bacteria will lose the purple color from the crystal violet stain.

This agar plate has only one species of bacteria growing on it. This type of agar can best be described as___________?

Differential EMB Agar

Select the correct taxonomic classifications for Ctenocephalides.

Domain Eukarya Kingdom Animalia

Trichomonas vaginalis belongs to _____________ and ______________?

Domain Eukarya, Kingdom Protista

What is the stain which can help visualize the structure formed by bacteria during unfavorable conditions that contains DNA and a small amount of cytoplasm encased by a protective outer covering which can then germinate during favorable conditions.

Endospore stain

What do bacteria form that may help them during unfavorable conditions such as heat, exposure to chemicals or radiation that allows them to remain metabolically inactive for many years and return to a vegetative form?

Endospores

Blood agar

Enriched and differential media

8. A chemical that you are about to use has the following symbols on its label. What do they mean? Exploding Bomb

Explosives Self-Reactives Organic Peroxides

There is no eye wash station in the microbiology lab room.

False The eye wash station is located in the sink in the back of the lab room.

The fire extinguisher in the microbiology lab room is located immediately next to the autoclave.

False The fire extinguisher is located next to the main entry/exit point for the room.

4. A chemical that you are about to use has the following symbols on its label. What do they mean? Flame

Flammables Pyrophorics Emits Flammable Gas Self-Reactive Organic Peroxides

Bacteria is growing on the agar but there is no change in the appearance or color of the blood agar and no lysis of red blood cells

Gamma Hemolysis (C section)

6. A chemical that you are about to use has the following symbols on its label. What do they mean? Gas Cylinder

Gases Under Pressure

The new GHS system provides information on the labels of the chemicals that you will use in lab. What does GHS stand for

Global Harmonized System

This bacteria image was taken using a high power electron microscope. What is the gram reaction, morphology and arrangement of these bacteria?

Gram positive cocci, strepto arrangement

What type of bacteria is this?

Gram-positive Staphylococcus

What type of bacteria is this?

Gram-positive Streptococcus

These are projections on mold that function for nutrient uptake, adherence to substrate, and hold up reproductive structures.

Hyphae

You accidentally drop a plastic test tube containing a liquid bacterial culture on your work station table. You have correctly followed the spill procedure. Where do you discard the tube and paper towels?

Infectious/biohazard, non-sharps

5. A chemical that you are about to use has the following symbols on its label. What do they mean? Exclamation Point

Irritant(skin and eye) Skin Sensitizer Acute Toxicity Narcotic Effects Respiratory Tract Irritant

You observe an organism under the light microscope in lab and have positively identified that it is multicellular and have determined that it belongs to the Domain Eukarya. You also observe no visible chloroplasts and can clearly identify separate visible body regions. This organism must belong to____________.

Kingdom Animalia

You observe an organism under the light microscope in lab and have positively identified that it is single celled. It has no internal membrane bound organelles. It clearly has several hairlike structures protruding from one end of an oblong cell shape. Your instructor tells you these are flagella. This organism belongs to____________.

Kingdom Bacteria

MacConkey agar (MAC) is most commonly used for the selective isolation of (a.)_____________ and differentiate them based on (b.)____________ resulting in a color change.

Lactose fermentation Gram negative species

Mold cultures grow?

Much slower than bacterial cultures

In which type of specialty stain is the background stained and the bacteria left unstained?

Negative Stain (bacilli)

You have just completed lab and you are cleaning up after the lab. Some of the laboratory waste contains human saliva on a cotton tipped applicator. What is the correct container to dispose of this waste?

Non-infectious/non-biohazard/non-sharps container

1. A chemical that you are about to use has the following symbols on its label. What do they mean? Environmental

Non-mandatory Aquatic toxicity

Concerning the inoculation techniques discussed in this lab, one difference between the "Spread Plate Method" and the "Streak Plate Method of Isolation" is___________ and one similarity is_________?

One difference between the two techniques is that the "Spread Plate Method " is used to evenly distribute the bacteria across the entire plate and a similarity is the end result should produce pure colonies in both methods.

It is important to note that Gram-positivity (the ability to retain the purple crystal violet-iodine complex) is not an all-or-nothing phenomenon but a matter of degree. There are several factors that could result in a Gram-positive organism staining Gram-negatively. Check all the factors that could apply to this situation.

Overheating during heat fixation The age of the culture Over decolorization

9. A chemical that you are about to use has the following symbols on its label. What do they mean? Flame Over Circle

Oxidizers

According to the 3 molds studied in this lab exercise the mold which has septate hyphae, conidiospores as the asexual spore and ascospores as the sexual spore would be identified as?

Penicillium and Aspergillus

What is the component of the bacterial cell wall that is actually being stained?

Peptidoglycan layer

This bacterial image demonstrates flagella in what is known as a/an__________ arrangement.

Peritrichous

If the bacteria appear purple in a properly performed Gram's stain procedure this means?

The cell is gram positive.

When talking about microscopy in this laboratory parcentric means?

The specimen should stay mostly in the center of the field of view when switching between objective lenses.

What does the term pleomorphic mean concerning bacteria?

These bacteria are constantly changing shape.

What can apply to this image?

These bacteria are pink and/or red due to the adherence of Safranin counterstain. This image is of bacilli bacteria. This image was most likely achieved using the Gram stain procedure. This image contains gram negative rods.

When performing a serial dilution, a student forgot to change the pipette and used the same pipette for every .5 mL transfer of the solution from tube to tube. Would these results be accurate and what would you predict the outcome would be?

These results would be inaccurate because the extra culture on the inside and outside of the pipette would increase the concentration of the next tube beyond the factored amount.

After performing a serial dilution a student counted 9 colonies on the 1:100,000 plate and 21 colonies on the 1:10,000 plate. Was this an accurate serial dilution? Why or why not?

This was not an accurate serial dilution because the number of colonies counted on the 1:100,000 plate was not within the target window and the difference in the count between the two plates was not close to a factor of 10.

According to taxonomy of living organisms yeast and mold both belong to the the Kingdom Fungi.

True

If you were viewing a bacterial slide using immersion oil you are at 1000x total magnification.

True

The non-infectious, non-biohazard, non-sharps waste container is a grey metal container with a clear liner and is also known as the regular trash.

True

When disposing of the environmental sample plates from this laboratory procedure they are to be considered a bio-hazard because they have been given nutrition, optimum temperature and time to grow.

True

Yeast convert carbohydrates to carbon dioxide and alcohols in the respiratory process known as fermentation.

True

The acid-fast stain is probably the second most frequently used stain. The acid-fast stain aids in diagnosis of what two diseases?

Tuberculosis and Leprosy

Which of the below is the correct procedure for washing your hands?

Wet your hands, apply soap, rub hands together while singing Happy Birthday twice, rinse well and dry, use the paper towel to turn off the faucet.

What color indicates a positive test reaction in the sugar tube?

Yellow

Which of the following is NOT a requirement for laboratory clothing?

You must wear a long sleeve shirt or blouse under your lab coat when in the lab.

The type of inoculation technique used in this lab exercise, when transferring the environmental sample to the agar plate, is known as____________?

a bacterial lawn

2. A chemical that you are about to use has the following symbols on its label. What do they mean? Skull and Crossbones

acute toxicity (fatal or toxic)

Clinically, most molds are identified by?

appearance of the mycelium hyphae structure asexual spore structure

Patient samples, after specimen collection, that were transported promptly but inaccurately labeled will be tested anyway.

false

A yeast cell?

is Eukaryotic is a single-celled organism is much larger than a bacterial cell reproduces by budding

What does the yellow color of a sugar test tube indicate?

it indicates that fermentation of that particular sugar has occurred

What could best be described as an easily disrupted chain of fungal cells partitioned by constrictions rather than septa?

pseudohypyha

The mold Rhizopus consists of which of the following?

sexual spores non-septate hyphae asexual spores

This specialty media was inoculated with 3 different species of bacteria (one type in each zone). Based on these results________________.

the color change occurred due to a dye or indicator that was added to the media during preparation. a growth inhibitor was used and resulted in no growth of one of the species.

At what "total magnification" should you view your gram stained slide, as well as all bacterial slides?

1000x (oil immersion)

In the serial dilution procedure of this laboratory exercise the dilution was increased with each transfer to the next tube by a factor of________?

10

Aseptic technique is a fundamental and important laboratory skill in the field of microbiology. Choose some examples of how or why aseptic technique would be used in a laboratory.

Proper aseptic technique prevents contamination of cultures from foreign bacteria inherent in the environment. Using proper aseptic technique can greatly minimize or even eliminate the risk of contamination.

The acronym for the use of a fire extinguisher is PASS.

Pull the pin Aim at the base of the fire Squeeze the lever slowly Sweep from side to side

List 4 protocols that must be followed for the collection of a biological specimen in order to obtain a timely and valid laboratory result.

Samples must be collected using proper collection techniques. Collected samples must be transported to the laboratory as soon as possible. It must be collected in the proper container. It must be collected in the presence of the patient and labeled with 2 identifiers (such as patient name and number).

An agar that contains a dye and/or indicator and a growth inhibitor as part of its ingredients can best be described as.

Selective and Differential

HE agar

Selective and Differential

Zone 1, 2 and 4 on this plate demonstrate 4+ growth. There is no growth on zone 3. Based on the results of this agar plate, this type of media could best be described as?

Selective and Differential (MAC agar)

A method used to dilute a substance in a stepwise manner into a solution with a constant dilution factor is known as?

Serial dilution

A zygospore would be considered a?

Sexual spore

7. A chemical that you are about to use has the following symbols on its label. What do they mean? Corrosion

Skin Corrosion/Burns Eye Damage Corrosive to Metals

The type of asexual spore for Rhizopus is called what?

Sporangiospore

What type of spores are shown here?

Sporangiospores