Micro Lab 1-6 Quizzes

cell completely surrounded by flagella

Peritrichous

Which does NOT affect resolution? Select one: a. size of the specimen observed b. numerical aperture of the objective c. wave length of light d. ability to gather light

a. size of the specimen observed

Negative stains are created by staining the background of the specimen with which type of stain? Acidic or basic?

acidic

single flagellum at each pole

amphitrichous

The species we will be using to perform the endospore stain in lab all belong to which genus

bacillus

The endospore stain is a differential stain used to detect the presence and location of ________ in bacteria

endospores

Artificial media cannot be both selective and differential.

false

Bacteria grow in pure cultures in nature.

false

Cholera (Vibrio cholera) is spread via airborne transmission.

false

In order to inoculate a slant, use one quick stabbing motion about half way down and pull straight back out.

false

Normal flora can never become pathogenic

false

Obligate anaerobic bacteria can be cultured on an agar slant.

false

Simple staining distinguishes organisms based on their interactions with multiple stains, while differential staining uses a single dye to emphasize particular structures in the specimen.

false

The endospore stain is used to distinguish between Gram negative and Gram positive cells.

false

Viruses can be viewed with the compound light microscope.

false

For proper sterilization, the instrument used for sampling and for obtaining the inoculum should be sterilized for at least ________ seconds

five

Waxy substances present in the cell wall, basis for acid-fast reaction. Produces unusual permeability properties

mycolic acids

In differential staining, the cells retaining the counterstain are considered to be:

negative

MacConkey agar is selective for Gram (one word) bacteria

negative

Total magnification = magnification of the __________ lens times magnification of the objective lens

ocular

Many of the commensal or mutualistic strains inhabiting our bodies are __________ pathogens capable of producing a disease state if introduced into a suitable part of the body.

opportunistic

defined as the ability to quickly focus while switching from a lower power lens to a higher power lens with a minimal amount of adjustment, using the fine focus knob only.

parfocal

Phenylethyl alcohol is the selective agent in PEA that inhibits Gram negative organisms by breaking down their membrane ___________barrier, thus allowing leakage of cellular potassium and disrupting DNA synthesis.

permeability

Gram __________cells have larger amounts of peptidoglycan

positive

In differential staining, the cells retaining the first or primary stain are considered to be:

positive

The decolorizer (or decolorizing agent) removes the ___________ stain selectively, based on the presence or absence of specific characteristics.

primary

The extent to which a material slows transmission speed relative to empty space is called the _____________of that material and is an important concept to know when using a light microscope, especially at the 100x objective.

refractive index

______________ is the ability to tell that two separate points or objects are separate.

resolution

Potato dextrose agar and sabaround dextrose agar are both ______________for yeasts, molds, and fungi.

selective

This type of media promotes the growth of a specific microbe while inhibiting the growth of certain other microbes.

selective

If cells appear individually, their arrangement is described as being the same as their _________for example, the arrangement of a species appearing as individual rods is bacillus.

shape

For the Lab 1 experimental procedures, nutrient agar (NA) plates will be inoculated using which type of streak method?

simple streak

d. As we go from low (10X) to high power (100X), the microscopic field gets __________ and the image gets __________, so you will need more light to view the specimen.

smaller, darker

Dyes are often added to growth media to aid in the identification of microbes. What could be the purpose of a dye in this case?

to indicate the pH level of the media

A transparent specimen will ________ light.

transmit

A hospital acquired infection is also known as a nosocomial infection.

true

After incubation, when interpreting results, you should handle plates carefully, because condensation and/or contaminated water droplets could drip from the plates.

true

Capsule production increases virulence in some microbes by making them less vulnerable to phagocytosis.

true

Endospores are dehydrated and show no metabolic activity.

true

Gram negative organisms frequently inhibit growth of Gram positive organisms when they are cultivated together.

true

Streaking for isolation is a dilution technique used to obtain a pure culture from a mixed population of cells.

true

Transient flora can be found in the layer of skin called the epidermis.

true

a Gram positive bacillus will grow best on phenyl ethyl agar (PEA).

true

Some bacteria live inside hot springs, while others have been found under the ice in Antarctica. These are examples of the _____________________ of microorganisms.

ubiquity

A specimen viewed with the oil immersion objective lens would have a total magnification of:

1000x

Which objective lens requires the use of immersion oil?

100x

Peptidoglycan and teichoic acid form a molecular complex with:

Crystal violet/iodine

Which is the most common type of biological vector of human disease?

D.arthropods

_______________Agar is commonly used to test for the presence of coliforms in environmental samples, which would indicate fecal contamination and the possible presence of dangerous pathogens.

Eosin Methylene Blue (EMB)

The study of factors influencing occurrence, transmission, distribution, prevention and control of disease is called:

Epidemiology

may be misidentified due to small halos which form as a result of cell shrinkage

Glycocalyx capsules

two or more flagella at 1 or both poles of the cell

Lophotrichous

Name the organism (Genus and species) that causes the most hospital acquired infections. Note: Be sure to spell and format the name of the organism correctly.

Staphylococcus aureus

An example of potential contamination of microbial culture is: Select one: a. Forgetting to heat/sterilize loops b. Keeping agar plates open c. All of the other choices are correct. d. Placing test tube caps on bench tops

c. all of the choices are correct

Which of the following is NOT true about contamination? a. changes a pure culture to a mixed culture b. alters drug sensitivity tests c. is more likely to occur when using proper aseptic technique d. produces inaccurate test results

c. is more likely to occur when using proper aseptic technique

Bacterial smears must be heat fixed prior to performing all of the following staining procedures EXCEPT for which of the following? Select one: a. Acid Fast Stain b. Gram stain c. Negative stain d. Simple stain

c. negative stain

Both simple stains and negative stains enhance the contrast of cells and allow for the visualization of ________

cell shape

Which of the following controls the amount of light passing through a slide on the microscope stage

condenser lens

Capsules don't take up acidic or basic stains.Instead, cell is stained with _______________and background stained with ____________

crystal violet, India ink

You heat fix a bacterial smear for all of the following reasons EXCEPT: Select one: a. Adhere bacteria to the slide b. Kill the bacteria c. Inactivate bacterial enzymes d. Help the bacteria grow

d. help the bacteria grow

A good bacterial smear should be thinly visible to the naked eye and approximately the size of a ___________

dime

All of the following are included in the "Five I's" culturing microorganisms in a laboratory setting EXCEPT: Select one: a. Incubation b. identification c. inspection d. Inoculation e. infection f. Isolation

e. infection

dormant structure formed within a microbial cell as a survival mechanism to resist damage from environmental factors (UV light, heat, chemicals, dehydration), ONLY in Gram positive bacteria

endospore

A blanket from a child with chickenpox is likely to be contaminated with the virus that causes chickenpox (Varicella-zoster virus). What is the blanket called?

fomite

You perform a Gram stain on a specimen. Under the microscope you see spherical pink cells this would indicate the specimen is:

gram negative cocci

You perform a Gram stain on a specimen. Under the microscope, you see spherical purple cells. This observation would indicate that the specimen is:

gram positive cocci

This is the oldest and one of the most common forms of microbial control, which can kill microbes by altering their membranes and denaturing proteins.

heat

Free-living microorganisms do not reside on or in a specific plant or animal ___________ and are not known to cause disease.

host

What is used to decrease the amount of light that is refracted when using a compound light microscope to view a specimen at the highest level of total magnification?

immersion oil

The sampling instrument used for obtaining an inoculum is called a/an ________

inoculating loop

Which of the following is NOT an example of a non-living reservoir for pathogens?

intermediate hosts

Sterilize/incinerate the loop between each streaked section increases the chance of ________ colonies on an agar plate

isolating

When viewing a specimen through the microscope, if you want the specimen to move to the right within your field of vision, which direction should you move the stage?

left

___________ is the ability of a lens to enlarge the image of an object when compared to the real object

magnification

Mannitol Salt Agar (MSA) is differential for fermenters/ non-fermenters of __________

mannitol

_____________ (general term) are used to provide all essential nutrients needed in order to culture microorganisms in a laboratory setting.

media

single flagellum at one pole

monotrichous

The Acid Fast test is specific to which genus of bacteria?

mycobacterium

During optimal growth conditions, an endospore will germinate to form a (one word) cell.

vegetative