Micro Lab

Front 1

Fomites

Back 1

surface areas or objects on which microorganisms grow and spread to other places.

Front 2

Nosocomial infection

Back 2

diseases that are from the hospital

Front 3

Bacterial colony

Back 3

A cluster of closely packed cells that originates from a single cell

Front 4

Bacterial culture

Back 4

the growth of cells on a nutrient medium

Front 5

Turbidity

Back 5

A cloudy appearance

-happened when the swan neck was tilted

Front 6

Whywere the plates in Sick Tootsie roll lab activity incubated at 25 C rather thanat 37 C?

Back 6

To prevent pathogen growth

Front 7

Why are agar media plates invertedwhen placed in the incubator or refrigerator?

Back 7

So condensation is not created and drips down onto the medium

Front 8

Coarse Focusing Knob

Back 8

knob that adjusts the focal plane in relatively larger increments.

Front 9

Fine Focusing Knob

Back 9

knob that adjusts the focal plane in relatively smaller increments

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Par Focal

Back 10

The capacity of an instrument to maintain focus regardless of the magnification used.

Front 11

Magnification

Back 11

The ability of a microscope to enlarge an object.

Front 12

total magnification

Back 12

depends on the combination of both the ocular and objective lens used.

Front 13

Resolution

Back 13

The smallest distance between two points on a specimen that can still be distinguished as two separate entities

Front 14

resolving power

Back 14

The ability of a lens to resolve two independent points as discrete entities. It is dependent on the wavelength (λ) of light used.

Front 15

Simple Microscope

Back 15

uses only ONE lens or a group of lenses in one unit to magnify objects (the ones we use in class)

Front 16

CompoundMicroscope

Back 16

uses TWO types of lens to magnify object.

Front 17

whatare the 2 factors that enhance resolution?

Back 17

wavelength (λ) of light used and the numerical aperture (NA)

Front 18

Whyis oil used with the 100X objective?

Back 18

prevents the loss of light caused by refraction and allows the light rays to continue in straight lines

Front 19

Culture medium

Back 19

The nutrients prepared for microbial growth.

Front 20

Nutrient agar slants

Back 20

for generating pure cultures

Front 21

Contamination

Back 21

the process by which unwanted microbes are accidentally introduced.

Front 22

Cross-contamination

Back 22

microorganisms are unintentionally transferred from one substance or object to another, with harmful effect

Front 23

Sterilization

Back 23

The point where no microbial forms are present including endospores and viruses.

Front 24

Aseptic techniques

Back 24

prevent unwanted microbes present in air, bodies, or other lab equipment from contaminating cultures or causing infection

Front 25

Examples of Aseptic techniques

Back 25

-disinfecting table tops before and after the experiment

- use gloves and lab coats

- sterile solutions, media, glassware and other equipment

-bunsen burner

Front 26

Inoculation

Back 26

introducing microorganisms into a sterile culture medium

Front 27

Inoculum

Back 27

the cells used to start a culture

Front 28

Pure culture

Back 28

consists of only one type of microorganism

Front 29

Mixed culture

Back 29

The population that contains more than one type of microbe.

Front 30

Sub culture

Back 30

a new culture made by transferring some or all cells from a previous culture to fresh growth medium

Front 31

Streak for isolation

Back 31

A technique for isolating colonies to generate pure culture of bacteria

-involves successive streaking to spread a few cells in the inoculum over an agar plate surface.

Front 32

Why is flamingthe inoculating loop/wire before and after each inoculation important?

Back 32

To make sure the previous bacteria is off and dead, before using other bacteria

Front 33

Why is holdingthe test tube caps in the pinky finger important?

Back 33

so the test tube cap won’t come in contact with any other contaminated surface

Front 34

Why is cooling the inoculating instrument prior to obtaining the inoculum important?

Back 34

If the inoculating instrument is too hot it may kill the bacteria you aretrying to obtain on contact

Front 35

Why is Flamingthe mouth of the test tube immediately after uncapping and again beforerecapping important?

Back 35

To make sure any bacteria present on the neck of the tubes is neutralized and keep the environment sterile

Front 36

Simple Stain

Back 36

A basic stain that is used to give color to bacterial cells.

Front 37

differential staining

Back 37

A staining procedure or media that allows one to distinguish types of bacteria based on how they stain or grow.

Front 38

Morphology

Back 38

The shape of a bacterial cell which can be rod, coccus, curved, or spiral

Front 39

Negative Stain

Back 39

A stain that is used to color the background of a slide leaving the bacterial cells colorless

Front 40

arrangements

Back 40

single cells, pairs, chains, packets, and clusters

Front 41

Whatinformation is obtained from a simple stain?

Back 41

cell shape, size, and arrangement

Front 42

Howto make smears from broth?

Back 42

1. With a sterile loop, transfer two to three loopfuls of the culture onto the glass slide.

2. spread the suspension into a thin, uniform dime-sized smear

3. Allow the smear to air-dry

4. Pass the slide over the flame four to five times to be heat-fixed

Front 43

Howto make smears from slant cultures?

Back 43

a

Front 44

What is the Purpose of the clean glass slide?

Back 44

a

Front 45

What is the Purpose of the thin uniform smear?

Back 45

a

Front 46

What is the Purpose of the air drying?

Back 46

a

Front 47

What is the Purpose of the heat fixing?

Back 47

kills the bacteria in the smear, firmly adheres the smear to the slide, and allows the sample to more readily take up stains

Front 48

State tworeasons why a negative stain is used

Back 48

-external structures of bacteria

-heat can distort capsules if used heat fixing

-uses acidic dies are repelled by the negative molecule

Front 49

Discussthe implications of capsules in bacterial diseases.

Front 50

Cana negative stain show the internal structures of a bacterial cell?

Back 50

No, only the external structures due to the negativity of the molecules in the bacteria

Front 51

Asyou rush to be in time for the Microbiology lab, you accidentally spill coffeeon your lab coat and the white fabric gets stained. Is this a biological stainor simply a compound that is capable of imparting color to the fabric? Explainyour reasoning.

Back 51

Compound that is capable of imparting of imparting color

Front 52

Principleof differential staining

Back 52

allows the technician to tell the difference between bacterial cell-wall structures just by viewing the color of the cells

Front 53

Why is differential stainingadvantageous over simple staining?

Back 53

The differential staining determine the shape, arrangement, and gram reaction while the simple staining only determine the morphology

Front 54

Gram stainingwith special emphasis on primary staining

Back 54

used with crystal violet and iodine solution

-turns blue/purple within the peptidoglycan

Front 55

Gram staining with special emphasis on mordent

Back 55

keeps the crystal violet on the gram-positive cell wall. Help keep the color of stain

Front 56

Gram staining with special emphasis on decolorizing agent

Back 56

The third step in the gram stain.

Uses alcohol to get rid of excess dye on the cell that should not be there

Front 57

Gram staining with special emphasis on counterstain

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Used with safranin to give the gram negative cells color

Front 58

Gram stainingwith special emphasis on the cell wall of a gram negative

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The dyes used on a gram negative stain, is negatively charged, as well are the walls on the cell, so it rejects the dye only staining the background

Front 59

Gram stainingwith special emphasis on the cell wall of a gram positive

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The positive stain, binds to the negative molecules on the cell wall and the cytoplasm

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Gram staining steps in order

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1. Crystal violet

2. Water

3. Iodine

4. water

5. decolorize with ethyl alcohol

6. water immediately

7. safarin

8. Rinse an blot

Front 61

Whichis the most crucial step in the Gram staining procedure? Explain.

Back 61

Decolorizing. If one over decolorizes, it will lose the primary stain and make the gram positive to appear negative

Front 62

streak plate method

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for isolation of pure cultures

Front 63

nigrosin

Back 63

stains background

Front 64

Gram’sstain helps observe which specific bacterial cell anatomy?

Back 64

the cell wall

Front 65

Whatis gram-variability?

Back 65

gram-positive cells may stain gram-negative using the gram stain procedure

Front 66

Describethree conditions that may result in gram-positive organism staininggram-negative.

Back 66

a) overheating, over decolorization, too much washing

b) The age of the culture – more than 24 hours old and may lose their ability to retain the crystal violet-iodine complex

c) The organism itself – some gram positive bacteria are more able to retain the crystal violet-iodine complex than others

Front 67

What is the medical importance for agram stain?

Back 67

-determines whether bacteria are present

-The difference between gram negative and gram positive bacteria can also be important when determining appropriate treatment for an infection

Front 68

Which one is more difficult to treat─an infection caused by Gram-negative bacteria or by Gram-positive bacteria?Explain.

Back 68

Gram negative have many layers of cell membranes so may be more difficult to kill because of all the protection

Front 69

Ona Friday evening, the health care personnel on duty forgot to refrigerate theurine sample and left it on the counter. On Monday, the sample was sent to thelab and the Gram stain showed great variability ranging from intense purple toshades of red. How would you account for this result?

Back 69

a

Front 70

method and steps used in an acid-fast stain

Back 70

1. Prepare smear, air dry, and heat fix

2. cover smear with bibulous paper and apply carbon fuschin. Let stain for 10 minutes

3. wash with water

4. decolorize with acid-alcohol

5. wash with water

6. conversation with methylene blue for 2 minutes

7.wash with water and blot with paper

Front 71

When would an acid-fast procedure be used

Back 71

when a cell contains a peptidoglycan-arabinogalactan cell wall surrounded by a layer of mycolic acid

Front 72

the unique molecule found in the cell wall of an acid-fast positive bacterium and explain why this bacterial is difficult to stain

Back 72

It contains a peptidoglycan-arabinogalactan cell wall surrounded by a layer of mycolic acid. It is a waxy type of fatty acid that requires a strong dyes like carbon fuschin with heat.

Front 73

method and steps of an endospore stain

Back 73

1. Prepare smears and heat fix

2. Place slide on beaker of boiling water and flood with malachite green and leave for 10 min.

3. wash with distilled water

4. Cover smear with safranin for 2 minutes

5. rinse with water

6. blot with paper and air dry

Front 74

the distinguishing chemical found in the coat ofendospores and explain its significance

Back 74

Dipicolinic acid. It gives resistance to heat, desiccation, and chemicals.

Front 75

the method of bacterial transformation withplasmid DNA

Back 75

bacteria take up free-floating DNA molecules. Plasmids carry full-length genes and can introduce new genotypes into the bacteria

Front 76

a

Back 76

a