Microbiology Lab Midterm

Front 1

Focal point

Back 1

the point at which a lens focuses light rays

Front 2

Focal length

Back 2

the length between the middle of the lens and the focal point

Front 3

a shorter focal length means___

Back 3

stronger magnification

Front 4

compound microscope

Back 4

◦image formed by action of >2 lenses

Front 5

the bright-field microscope

Back 5

produces a dark image against a brighterbackground

Front 6

abilityof a lens to separate or distinguish small objects that are close together

Back 6

microscope resolution

Front 7

shorterwavelength means ___

Back 7

greater resolution

Front 8

Why do we use oil in microscopy?

Back 8

to increase resolution and numerical aperture

(light rays that did not enter the objective lens due to reflection and refraction will now do so)

Front 9

working distance

Back 9

—distance between the front surfaceof lens and surface of cover glass or specimen when it is in sharp focus

Front 10

In Fluorescence Microscopy, we expose specimen to ______

Back 10

ultraviolet, light or blue light

Front 11

In fluorescence microscopy, we stain the specimen with__

Back 11

flurochromes to tag specific cell constituents foridentification of unknown pathogens

Front 12

What type of microscopy allowsfor study of microbial morphology in great detail??

Back 12

Electron

Front 13

____ can determine actual in situ location of microorganisms in ecologicalniches

Back 13

Scanning electron microscope

Front 14

to clean the oil lens, we can use___

Back 14

xylene

Front 15

Mannitol salt agar

Back 15

selective: for staphylococci

differential: based on the release of acidic products

Front 16

MacConkey Agar

Back 16

selective: for gram -
differential: lactose fermenters/ non-fermenter

Front 17

Blood agar

Back 17

Enriched: blood
differential: hemolytic/ nonhemolytic

Front 18

Eosin Methylene blue Agar

Back 18

selective: for gram -

differential: use of lactose/ sucrose as carbon/energy sources

Front 19

What are fastidious organisms?

Back 19

Fastidiousorganisms:require specialized environments due to complex nutritional requirements.

Front 20

Size of bacterial cells

Back 20

•0.2- 2.0 µm diameter

•2– 8 µm length

Front 21

What's a mordant?

Back 21

Mordant – intensify the stain ,increase the affinity of a stain for a specimen , to coat a structure to make it thicker and easier to see after it is stained

Front 22

Examples of simple stains

Back 22

Methylene blue , carbolfuchsin, crystal violet , and safranin

Front 23

capsulematerials are ____in water , and may be ____during intense washing

Back 23

soluble
removed

Front 24

Capsules appear as ___ surrounding stained bacteria

Back 24

halos

Front 25

Bacteria that stain acid positive

Back 25

Mycobacterium & Nocardia and actinomyces

Front 26

Acid positive bacteria contain

Back 26

mycolicacids

Front 27

Hot stain is also called

Back 27

Ziehl–Neelsen Method (5% phenol in carbolfuchsin)

Front 28

Cold stain is also called

Back 28

Kinyoun modification (15% phenol in carbolfuchsin)

Front 29

Two medically important bacteria that form endospores

Back 29

Bacillus & Clostridia

Front 30

•Bacteriacan form endosporesin approximately ____hours after being exposed to adverse conditions.

Back 30

6 to 8

Front 31

Young cultures of spore-forming microbes may not demonstrate any endospores because ______

Back 31

the vegetative cells may not have been subjected to sufficient stress to stimulate sporulation.

Front 32

To improve the odds that spore formers can be detected, most methods suggest _____

Back 32

using cultures that are 18 to 36 hours old

Front 33

What's a wire loop made out of

Back 33

platinum

Front 34

proper temperature in incubators

Back 34

37 for bacteria

28 for fungi

Front 35

how do we clean petri dishes/ tubes/ infected material?

Back 35

put in autoclavable bags→into autoclave

Front 36

how do we clean cotton swabs/ tips/ slides

Back 36

into a container containing disinfectant

Front 37

BNR

Back 37

Basic nutritional requirements (C, N, H, O, P, S)

Front 38

how much agar per 100 ml h20

Back 38

1.5 gm

Front 39

Nutrient broth ____gm/L

Back 39

13

Front 40

Nutrient agar ____ gm/L

Back 40

28

Front 41

Blood agar____gm/L

Back 41

40

Front 42

MacConkey agar_____gm/L

Back 42

50

Front 43

Autoclave heats at ___C for ____ minutes

Back 43

121

15-20

Front 44

Where does the autoclave get all that heat and pressure?

Back 44

from water vapor

Front 45

Cholera agar is

Back 45

selective media for Vibrio cholera
(it's the only type of bacteria that grows at 8.2 pH)

Front 46

SS agar is

Back 46

Selective for Salmonella and Shigella

Front 47

what does salmonella cause

Back 47

typhoid

Front 48

what does shigella cause

Back 48

dysentery

Front 49

what color are salmonella colonies

Back 49

black

Front 50

what color are shigella colonies

Back 50

yellow

Front 51

chocolate agar is

Back 51

selective for Haemophilus influenzae and Niserria (meningitidis amd gonorrhea)

Front 52

example of an acidic stain

Back 52

safranin

Front 53

example of a basic stain

Back 53

methylene blue

Front 54

Why do we do gram stains?

Back 54

for the gram rxn

to see the size of cells

to see the shape of cells (cocci, bacilli, curved, spiral)

to see the arrangement of cells (chains, diploid, tetrads, clusters. single)

Front 55

Treponema pallidum is

Back 55

a spiral shaped bacterium that causes syphilis

Front 56

klebsiella pneumonia is

Back 56

a gram +, diplococci bacteria with a capsule

Front 57

All cocci are gram + except

Back 57

nisseria

Front 58

All bacilli are gram - except

Back 58

bacillus, diptheria, clostridium

Front 59

Arrangement for bacilli

Back 59

single, stacks, chinese letter

Front 60

what does clostridium cause

Back 60

gangrene

Front 61

Differences between capsulated and non-capsulated bacteria

Back 61

capsulated is:

resistant to phagocytosis

more virulent

has a store of nutrients and water

can adhere more easily

Front 62

3 Encapsulated bacteria

Back 62

klebsiella pneumonia, bacillus, streptococcus mutans

Front 63

why do we air dry in capsule staining

Back 63

we don't want to dry out/ ruin the capsule

Front 64

Stains of gram stain

Back 64

Crystla violet then safranin

Front 65

Strains of capsule stains

Back 65

Congo red then acid fuchsin(2 min)

Front 66

Fixative of capsule stain

Back 66

acid alcohol (1 min)

Front 67

decolorizer of capsule stain

Back 67

h20

Front 68

steps of germintion

Back 68

activation, initiation, outgrowth

Front 69

most important chemical compound in endospores

Back 69

calcium dipicolinate

Front 70

Stains of endospore staining

Back 70

Malachite green (5-7min over b. h20) and safranin (2 min)

Front 71

decolorizer in endospore stain

Back 71

h20

Front 72

fixative in endospore stain

Back 72

h20

Front 73

TB must be cultured on ____ for ___

Back 73

Löwenstein–Jensen medium,

Front 74

Stains in acid fast stain

Back 74

Carbolfuchsin(5min) then methylene blue (2mins)

Front 75

decolorizer in acid fast stain

Back 75

acid alcohol

Front 76

what can we see in sputum?

Back 76

epithelial cells

streptococci

dead WBCs

M-TB