Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology Lab > Exam 1 Objectives > Flashcards

Exam 1 Objectives Flashcards

1
Q

what is a simple microscope

A

it is used to produce an enlarged image of an object placed within its focal length; single lens; no condenser

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is a compound microscope

A

3 to 5 lenses; better magnifying power; has condenser lens; illuminator is the source of light; used for detail and studying structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the power of the objective and ocular lenses

A 
ocular=10x
oil immersion=100x
scanning=4x
objective=10x
objective=40x
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

explain the use of immersion oil and how it allows the microscopist to obtain greater resolution

A

placing a drop of oil with some refractive index as glass between the cover slip and objective lens eliminates two refractive surfaces, can achieve greater magnification while preserving resolution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

describe resolving power

A

the actual measurement f how far apart two points must be for microscope to view them as separate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

describe numerical aperture

A

measure of a lens ability to capture light coming in from specimen and used to make an image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what does the blue light equal

A

shorter wavelength

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

explain why a blue filter is used beneath the condenser of our microscopes

A

it increases contrast between a specimen and its background, also has better higher resolution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

describe the change in working distance as magnification increases

A

as magnification increases, working distance decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what does parfocal mean

A

having corresponding focal points in all the same plane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the advantage to the microscopist parfocally

A

the advantage is it allows more accurate focusing at maximum focal length and then zooming back to a shorter focal length to compose the image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

describe the change in the size of the field of view as magnification increases

A

as magnification increases, size of field decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the field of view

A

how much of your subject you see through the lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how does the orientation of the image change under the microscope compared to the orientation of slide

A

the optics of the microscope inverts the image(turns it upside)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

compare the size of human blood cells with yeast cells and typical bacilli and cocci

A

human blood cells= 12um
yeast= 3-4 um
bacilli= .2-2 um
cocci= 1-2 um

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is meant by depth of field

A

distance through which you can move the specimen and still have it remain in focus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is a pure culture

A

lab culture with one species of organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is a mixed culture

A

lab culture with two species of organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is aseptic

A

without contamination of culture, the sterile medium or the surroundings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is sterile

A

killing all forms of microbe life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is contamination

A

the unintended introduction of microbes in areas or on surfaces they should not be

22
Q

what is broth

A

used to grow stock culture

23
Q

what is a slant

A

a growth medium in a test tube; this provides the medium with more surface area for microbial growth

24
Q

what is meniscus

A

when a liquid is in a cylinder the liquid will be higher than in the middle creating a concave

25
Q

identify the times when a microbiologist must use a pure culture

A

1-look for a particular pathogen that caused a disease
2-to look for antibiotic susceptibilities on that pathogen
3-to inhibit evolutionary change

26
Q

describe characteristics of a properly a adjusted bunsen burner flame

A

bunsen burner produces a flame with two cones, an outer cone that is relatively colorless and an inner cone that is blue in color and should be about one inch in height

27
Q

describe the instruments microbiologists most often use to transfer microorganisms

A

inoculating loop
inoculating needle
nutrient agar slants

28
Q

what is a mohr pipette

A

they have markings that always end before the tip

29
Q

what is a serological pipette

A

have marks that continue all the way down the tip

30
Q

what is the meaning of the markings on the top end of a serological pipette

A

they indicate whether the pipette is a blow out pipette and the size and the measurement graduations of the pipette

31
Q

identify aseptic technique procedures that are performed when working with microorganisms

A

inoculating loop is placed at the tip of the inner cone until it is bright orange and then it is dragged through the flame before and after transferring a microorganism. The test tube containing the microbe is also run through the flame before and after the transfer

32
Q

explain how to protect yourself from laboratory acquired infection

A

lab coat and goggles and closed toed shoes; keep personal things away from the desk

33
Q

why is a new stock culture always made as the first incoculation from a stock culture tube

A

we make a stock culture as a duplicate cuz the stock culture that we used for transfer is no longer sterile

34
Q

what is a serial dilution

A

series of controlled transfers down a line of blank dilution, reduces the concentration of a culture(produce between 30-300 colonies when plated
provides a way to calculate the original concentration

35
Q

what is a tube with solidified agar in an upright position, as opposed to a slant

A

agar pour (deep)

36
Q

what does TNTC mean

A

too numerous to count, >300

37
Q

what does TFTC mean

A

too few to count, <30

38
Q

this is bacterial colony shaped like a double convex lens

A

lenticulate

39
Q

this means no growth

A

NG

40
Q

what does CFU mean

A

colony forming units from a single, pair or chains of bacterial cells

41
Q

this is a count viable bacteria (meat)

A

heterotrophic plate count

42
Q

this is a plate count agar, medium used to assess total number of viable growth, not a selective medium

A

standard method agar

43
Q

what is a colony forming unit

A

1 cell or a group of 2 or more cells which when plated give rise to a colony

44
Q

why are plates labeled on the bottom of the dish and inverted for incubation/storage

A

in case of lid loss, the label will still be on bacterial culture and to avoid condensation disturbance of growth as well as rehydrate bacterial colonies

45
Q

how to calculate the dilution factor for each dilution made

A

D2=V1D1/V2

46
Q

what is countable plate

A

between 30-300

47
Q

why plates with fewer or greater number of colonies are unreliable

A 
<30= not true representation of original concentration
>300= overlapping colonies can cause human error in the counting process
48
Q

what is the basic assumption made concerning the number of bacteria in the inoculum and the number of colonies on a plate

A

the number of colonies is equal to the number of bacteria transferred

49
Q

what is the formula used to determine the concentration of bacteria in the original sample after making plate counts from a dilution series

A

original cell density=colony forming units/(dilution written on tube)x(volume transferred to the plate)

50
Q

reasons a microbiolgist might wish to ascertain the number of bacteria per milliliter in a sample of meat

A

to understand the likelihood that a specific pathogen capable of causing disease will be present in the food and that the food will spoil

51
Q

maximum number of bacteria per gram of meat for the meat to be sellable

A

10^6

52
Q

what are the limitations of the procedures used to estimate bacterial numbers

A

only bacteria capable of growing in the culture medium under the environmental conditions provided will be accounted for

Microbiology Lab (25 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions