Microbiology Lab Final (past pre. lab quizzes)

when you collect a loopful of culture from the stock tube, should you/can you see the inoculum on the loop?

no ( should no be visible).

when inoculating a slant with. bacteria, what pattern should the inoculating loop move in?

zig zags

To inoculate a slant, you start at the _____of the slant and move to the ______.

bottom of the agar (lowest part of the agar surface)

top of the agar

You use an _____ to inoculate agar deeps, which ________

- inoculating needle

-lacks a loop and instead ends in a point

To inoculate an agar deep, insert the tool at the center of the deep _______.

Then gently remove the tool by ______.

- all the way to the bottom of the deep

- by following the same path as insertion

What color does the inoculating loop turn when exposed to the Bunsen burner flame?

What parts of the loop turn this color?

- red

- loop and the wire (but not the handle)

The hand holding the _____ is used to remove the cap from the tube.

Was the cap ever placed on the lab bench/work surface?

- the inoculating loop

- no, the cap is carefully held the entire time

hand sanitizer kills all the possible disease causing agents from your hands (T/F)

false

what is meant when you are asked to "inoculate your culture"

aseptically transfer an organism from one media to another

The mat of cells formed at the surface of a static broth is called a _____

pellicle

What is the best way to handle cultures in this lab?

treat all cultures as if they were of high virulence

How should you dress for the lab?

wear closed toed shoes; and long pants

what does PPE stand for?

Personal Protective Equipment

Which of the following are PPE?

- safety class/goggles

- hat

- gloves

- lab coat

- safety glass/goggles

- gloves

- lab coat

Safety goggles should be worn at all times while working in a microbiology lab (T/F)

True

You are allowed to have long hair NOT pulled back in class, as long as you are through working (T/F)

false

Disposable latex/nitrile gloves

are always to be worn

Johnny was working in the microbiology lab one afternoon and received a phone call from his Mom. he decided to pull out his phone while in lab and with his gloves still on. Did Johnny spread bacteria to his phone?

Yes

which of the following personal items should be out during a microbiology lab

- water bottle

-personal writing utensil

- food

- headphones

- cell phones

- none of the provided answers

- none of the provided answers

Which of the following are discarded in the regulated medical waste (biohazard):

- used agar plates and gloves

- used test tubes

- paper towels and kimwipes

- slides and coverslips

- used agar plates and gloves

In the event of a dropped or spilled culture, the following procedure is in effect:

the individual. is not to move about or attempt to clean up the spill, instead the individual is to stand still and call for help

Which of the following statements about aerosols is true ?

- microorganisms rarely inhabit aerosols droplets in the air

- it is very difficult to generate aerosols without sophisticated equipment used

- aerosols may be composed of liquid or solid particles

- aerosols may be composed of liquid or solid particles

How many drops of water do you add to the smear that you are preparing?

Which do you do first, dry the slide on the warmer or heat fix the slide?

- 1

- dry the slide on the slide warmer

You should not wear gloves while heat fixing your slide because gloves are flammable (T/F)

true

Where do you put your hands to move the microscope from the cabinet?

- one hand at the arm of the scope

- one hand at the base of the scope

how do you change from one objective lens to another?

- rotate the revolving nosepiece (black disk above objective lenses)

What position should the objective lenses be in to add immersion oil?

the open spot directly over the slide

When you are finished viewing a slide under 100x oil immersion, what do you do? put the following in order:

1. lower the mechanical stage

2. remove the slide

3. wipe the 100x lens with lens paper

4. rotate the objective lenses to the empty spots

before turning off the microscope, you should lower the brightness all the way (T/F)

true

the stab inoculation method will be used when inoculating:

- trypticase soy agar deeps

- trypticase soy agar plates

- trypticase soy broth

trypticase soy agar deeps

Which of the following statements is most true about the growth of microorganism in broth cultures?

- motility creates turbidity in broth cultures

- bacterial growth creates mycelial mats in roth cultures

- bacterial growth creates turbidity in broth cultures

- bacterial growth created turbidity in broth cultures

Yeast cells are typically observed under 40X objective. the total magnification of the specimen is

400

Heat fixing a smear refers to

passing a slide with a smear through a flame 2-3 times

The main purpose of staining microorganisms with a simple stain is to ______

see them more easily under a microscope

Heat fixing is an important step in staining because

it kills the microorganism and ensures its attachment on the slide

crystal violet is a

basic dye

The gram stain is a _____ stain

differential

gram's iodine in gram staining act as a

mordant

all microorganisms stain by gram's method (T/F)

false

control experiments are required to be performed to validate executions of your test experiment (T/F)

true

Bacteria are _____ while yeast are _____.

- prokaryotic

- eukaryotic

The possibility of observing no cells after adding a heavy inoculum on the staining slide might be because

- you forgot to heat fix the smear

- you forgot to use primary stain

- you forgot to use mordant

- you use a hot inoculating loop to add the organism to make a smear

- you forgot to heat fix the smear

In this class at 100X magnification, gram positive controls should always appear purple after gram staining (T/F)

true

capsules enable bacteria to adhere to surfaces in many natural environments (T/F)

true

Bacterial capsules are:

- inside prokaryotic cells

- outside prokaryotic cells

- inside eukaryotic cells

- outside eukaryotic cells

outside prokaryotic cells

The main objective of using crystal violet for capsule staining is to

- stain the capsule

- stain the bacterial cell

- stain the bacterial cell and background

- all choices are correct

stain the bacterial cell and background

Most bacterial extracellular polymers such as capsules are composed of _______

- polysaccharides

- disaccharides

- proteins

-lipids

polysaccharides

The surrounding of the cell after a mature spore is formed in a cell is called

- mycelium

- vegetative cell

- sporangium

- free spore

sporangium

Endospores can be observed without using spore staining technique when using

phase contrast microscope

How do you apply the coverslip?

lower the cover at an angle over the dop of water

You need a very large amount of inoculum when making a wet mount (it should be a big chunk on the end of the inoculating loop) (T/F)

false

a wet mount is best described as:

a method for observing live cells under a microscope, which does not involve staining the organisms

Bacteria appears pigmented in the soft-agar deeps due to the presence of

- agar

- yeast extract

- triphenyltetrazolium chloride

- p aminobenzaldehyde

triphenyltetrazolium chloride

when agar plates are closed and taped shut, they should be stored with the lid _____

against the table

What are some challenges with staining cells in order to see their flagella?

- the tendency of flagella to detach during staining

- differences in flagellin proteins

- variations in the dye

- all answers are correct

all of the above

Human GI tract are an anaerobic environment meaning that there is a lot of oxygen present allowing for certain types of organisms to survive (T/F)

false

extremely stringent obligate anaerobes (any exposure to oxygen) cannot grow in agar deeps or anaerobe jars (T/F)

true

Cells can be considered mitile if they use ___ to tumble or swim (select all that apply)

- cilia

- brownian movement

- flagella

- cilia

- flagella

turbidity is...

the cloudiness in a liquid culture

While a microbial culture is growing exponentially, its optical density increases (T/F)

true

We can use a spectrophotometer to measure the optical density of a culture. This alone can tell us the viable cell number (T/F)

false

The. growth of a well suspended microbial culture is accompanied by

an increase in optical density

What would be the results of insufficient decolorization when performing the Gram stain?

gram negative organisms may appear gram positive

The possibility of observing no cells after adding a heavy inoculum on the staining slide might be because

you forgot to heat fix the smear

How do you mix broth culture before streaking?

what side of the plate do you label?

- gently tap the bottom of the table

- the dish ( the part that the agar sits in)

How long should the loop cool after flames sterilization?

Where does the lid of the T-streak go while the plate is being streaked?

- 10 to 20 seconds

- it is held slightly above the plate at an angle (like a clam shell)

When does the inoculating loop need to be sterilized?

- after streaking the second section (area 2)

- after streaking the third section (area 3)

- after streaking the first section (area 1)

- before entering the stock culture tube

all of them

Before adjusting the volume of liquid that a pipette can hold, what do you need to do first?

unlock the pipette by moving the volume lock from locked to unlock

The T-streak is:

a method for separating microbes by spreading them on agar

final dilutions have positive exponents

(T/F)

false

What is a pure culture?

contains only one species of microorganism

a viable number is

the number of cells capable of division on a solid medium

dilution factors have positive exponents (T/F)

true

selective agents are added to the media to inhibit the growth of unwanted microorganisms (T/F)

True

When selective agents are added to a media, it ______

inhibit growth of unwanted organisms from a mixture of other organisms

Media that contains a wide variety of nutrients and that support the growth of many different kinds of microorganisms are called ______ media

all purpose

It is impossible for a thermophile to survive at human body temperature (37C) even for brief periods (T/F)

false

Which of the following is not a term used to classify temperature growth ranges of bacteria

transmogrophilic

In regards to temperature preferences, most organisms are ____

mesophiles

generally differential media is used to

distinguish one type of microorganism from all others in a mixed culture

growth rate measurements must show an increase in numbers or turbidity (T/F)

TRUE

every microorganisms has an optimum, a minimum, and a maximum growth temperature (T/F)

true

plasmoptysis occurs when you rapidly ___ the osmotic pressure outside the cell and the cell wall busts and the cells die

- increase

- decrease

decrease

Saltwater dwelling bacteria can be classified as?

- saccharophilic

- halophilic

- aquaphilic

halophilic

tonicity refers to the normal osmotic pressure extended by body fluids (T/F)

true

The type of metabolism characteristic of strict aerobes is called respiration, whereas _____ is the type characteristic of strict anaerobes

- anaerobic respiration

- fermentation

- inorganic respiration

fermentation

fermentation does not require oxygen as a terminal electron acceptor (T/F)

true

metabolism in which oxygen is the terminal electron acceptor is called __________, __________ are examples of organisms which only have this type of metabolism

- respiration, strict aerobes

- fermentation, strict aerobes

- respiration, strict anaerobes

- respiration, facultative anaerobes

respiration, strict aerobes

in regards to temperatures preferences, most organisms are ______

- mesophiles

- halophiles

- psychrophiles

- thermophiles

mesophiles

in any solution, the dissolved material is called the _____, and the fluid on which it is dissolved is called the __________

solute, solvent

Microbes that are capable of either fermentation or respiration are called:

facultative anaerobes

fermentation is one of the two ways that microorganisms derive energy from nutrients in their environment. the other way is called _____

respiration

if the inoculated phenol red tube turned from red to yellow, the bacteria are excreting basic compounds

(T/F)

False

when methyl-red reagent is added to a tube of MR-test tube post 48 Hour incubation, a positive tube will turn red throughout the tube (T/F)

True

The MR test indicated mixed acid production via glucose fermentation

(T/F)

true

The methyl red test was made to identify enteric bacteria, so a positive test will appear a bright red color. what is the color of a negative results

- slight red

- orange

- yellow

- all choices

all choices

the starch plate is positive when?

there is a clear area around the bacteria

_____ is the glycosidase that hydrolyzes starch and causes a zone of hydrolysis

amylase

gelatin is made by boiling a protein called ______. this causes the protein to _____

collagen, denature

milk is white in color because the calcium caseinate present is water insoluble and exists in suspension as a true colloid

(T/F)

true