Lab Quiz Cards

Question 1

A single medium, such as trypticase soy agar can support the growth of all organisms in the lab. True or false?

Answer 1

False - there is no medium that support the growth of all organisms.

Question 2

When preparing a slide, a liquid organism would not require the initial drop of water. True or false?

Answer 2

True.

Question 3

The total magnification of the microscope is the product of the ___ lens and the objective lens magnification.

1. focal piece
2. eyepiece
3. nose piece

Answer 3

eyepiece

Question 4

Why is sterile technique so important? Give two reasons.

Answer 4

1. prevent contamination of the culture from environmental organisms
2. prevent culture of contaminating you or others

Question 5

Why should plates be inverted when being incubated?

1. To view the cells correctly
2. To avoid condensation
3. To avoid outside contamination

Answer 5

to avoid condensation

Question 6

All of the following are true when you use the oil immersion lens except:

1. you are using the 100x objective
2. you are adding a drop of oil to compensate for refraction
3. you are adding a drop of oil to compensate for reflection

Answer 6

you are adding a drop of oil to compensate for reflection

Question 7

The resolving power of a microscope is described as the ability of the microscope to

Answer 7

clearly separate two objects that are very close together

Question 8

specimens can be observed at the atomic level using an

Answer 8

atomic force microscope

Question 9

What kind of charge do basic dyes have?

Answer 9

positive

Question 10

what is the correct order in the basic staining procedure?

Answer 10

smear, fix, stain

Question 11

what are the two types of bacteria and what are their colors?

Answer 11

gram positive - purple

gram negative - pink

Question 12

is applicable to only a few groups of bacteria and usually shows the spores as green structures among a background of pink cells

Answer 12

endospore stains

Question 13

what is a diluent?

Answer 13

the liquid used to dilute a sample

Question 14

you have added .1ml of the original culture to 9.9ml of water. How much have you diluted the sample?

Answer 14

1:100

Question 15

what is serial dilution?

Answer 15

preparing a dilution of the original culture in multiple steps

Question 16

All of the following are true of viable bacteria except

1. they are not growing
2. they are growing and dividing
3. can be measured by plate counts

Answer 16

they are not growing

Question 17

In an agar deep, where do obligate aerobes grow?

Answer 17

at the surface of the agar deep

Question 18

what is an agar deep?

Answer 18

test tube filled almost to the top with agar

Question 19

what the thermal death time (TDT)

Answer 19

minimum time required to kill all microbes at a set temperature

Question 20

what is the thermal death point (TDP)

Answer 20

the lowest temperature at which all microbes are killed in a culture within a given time

Question 21

Out of the following microorganisms, which one would penicillin be able to kill?

1. staphylococcus epidermidis
2. e. coli
3. pseudomonas aeruginosa

Answer 21

staphylococcus epidermidis

Question 22

liquid media containing heat-sensitive components would best be sterilized by

Answer 22

membrane filtration

Question 23

the zone of inhibition produced by a bacteria that is sensitive to an antibiotic will depend on….

Answer 23

the size of the antibiotic molecule and the concentration of antibiotic on the disc

Question 24

What are two precautions that need to be taken when dealing with UV light?

Answer 24

do not look directly at it and do not put it to your skin because it causes mutations

Question 25

what are the typical conditions for sterilization?

Answer 25

121 degrees celsius at 15 psi for 15 minutes

Question 26

what is the zone of inhibition?

Answer 26

region that surrounds a chemical saturated disc where bacteria are unable to grow

Question 27

acinetobacter is

Answer 27

naturally competent

Question 28

what is DNA transformation?

Answer 28

transfer genes of one bacterium to another

Question 29

Acinetobacter StrS cells will grow on TSY + streptomycin plate. True or false?

Answer 29

False

Question 30

propionbacterium will grow in what conditions? 1. plate incubated aerobically 2. plate incubated anaerobically 3. surface of the agar deep 4. bottom to middle of the agar deep

Answer 30

plate incubated anaerobically/bottom to the middle of the agar deep

Question 31

what happens to staphylococcus aureus when it is plated on a mannitol salt plate?

Answer 31

it will appear yellow because it is able to utilize mannitol

Question 32

why is salt used in the mannitol salt plate?

Answer 32

to prevent the growth of gram negative bacteria

Question 33

A commensal organism is harmful for the host. True or false?

Answer 33

false

Question 34

a pink color on macconkey agar tells us what?

Answer 34

lactose has been fermented by a gram negative bacteria

Question 35

the indole test indicates whether the bacteria has the enzyme to break down what?

Answer 35

tryptophan

Question 36

what happens when there is an indication of tryptophan in a broth?

Answer 36

a red/pink ring will form in the indole test when kovacs regeant is added

Question 37

why is methyl red added to each of the sugar fermenting tubes

Answer 37

because it is a pH indicator

Question 38

what is one coccus gram negative bacteria from your throat culture?

Answer 38

moraxella catarrhalis

Question 39

what is a beta hemolytic bacteria that may be found in a throat culture?

Answer 39

streptococcus pyogenes

Question 40

what does the oxidase test indicate?

Answer 40

is cytochrome c oxidase is present in a bacteria

Question 41

what is a indicative oxidase test?

Answer 41

a dark purple blue color

Question 42

ELISA stands for

Answer 42

enzyme linked immunosorbent assay

Question 43

the elisa assay technique is based on the formation of

Answer 43

antigen-antibody complex

Question 44

what does lauryl lactose sulfate selectively enrich for

Answer 44

coliforms

Question 45

what is the best way to measure the presence of viable bacteria that may not form colonies on plates easily

Answer 45

multiple tube fermentation method

Question 46

three characteristics of indicator organisms

Answer 46

- non pathogenic - highly occurring in feces - easy to detect compared to waterborne pathogens

Question 47

what kind of medium is the brilliant green broth?

Answer 47

selective

Question 48

what kind of growth does brilliant green broth support?

Answer 48

coliforms

Question 49

if all the tubes in your MPN method for determination of viable bacteria are positive, then you will start with

Answer 49

a diluted sample of the water