Micro Lab Practical 1 Review

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created 4 years ago by kaworu27
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Microbiology
Chapters 1-10, 12, 13, 16
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1

Cells that are round have the following morphology:

Coccus

2

Cells that are rectangular in shape have the following morphology:

Bacillus

3

Long thing flexible cells shaped like a corkscrew, containing axial filaments, have the following morphology:

spirochete

4

Two round cells that are physically stuck together have teh following arrangement:

diplococcus

5

several rectangular cells that form a chain have the following arrangement:

Streptobacillus

6

Cells shaped like a comma have the following morphology:

Vibrio

7

A simple staining employs the use of a ___ charged dye to stain cells that are ___ charged:

Positively, Negatively

8

True/False:

The purpose of a heat-fixation is to kill the organisms, they will adhere to the slide, and it will stimulate motility by activating flagella

False

9

Smears should never be heat-fixed while they are still wet because

creates living aerosols

10

True/False:

Simple staining is not very useful for examining living organisms or for testing an organisms' motility.

True

11

True/False:

When performing negative staining, it is important to heat fix the microbial smear prior to staining.

False

12

Cells that are wavy, large, and rigid, with external flagella, have the following morphology:

Spirillum

13

After performing a negative stain, for the most part, how will the cells look?

colorless

14

Four or more bacilli shaped cells that are arranged in a long chain:

Streptobacillus

15

Multiple Choice:

Living cells have a net (negative OR positive) charge and will (attract OR repel) negatively charge stains.

Negative, Repel

16

True/False:

Gram negative cells have a thick cell wall and are surrounded by an additional layer of lipid.

False

17

When Gram-negative cells lyce in KOH test, what cellular material causes the characteristic "stringing"?

Chromosomal DNA

18

In the Gram stain, the primary stain is:

Crystal Violet

19

If the iodine step is missed, Gram positive cells will appear ___ at the completion of the protocol:

Red

20

True/False:

Gram-positive cells are susceptible to Vancomycin while most Gram-negative cells are resistance.

True

21

Bacterial cells that are actively undergoing metabolic processes and binary fission are referred to as:

Vegetative

22

the two clinically significant genera that are capable of producing endospores:

Bacillus, Clostridium

23

Why is steam used during endospore staining?

Heat i necessary for driving stain into the spore coat

24

In the capsule stain, what stain serves as the negative stain?

Congo Red

25

In the capsule stain, what stain serves as the positive stain?

Maneval's

26

Four chemical elements essential for comprising 98% all living things:

Carbon (C), Hydrogen (H), Oxygen (O) and Nitrogen (N)

  • Phosphorus (P) and Sulfur (S) are also necessary
27

What are the optimum temperatures at which all living organisms grow?

Body temperature 37*C

Room temperature 20-27*C

Refrigerator temperature 4-10*C

Freezer temperature -20*C

Note: Some microbes grow above or below these temperatures

28

Members of Microbial world

Living Members:

Nonliving Members:

Living: bacteria, protozoa, fungi, algae, and parasitic worms

Nonliving: viruses, viroids, and prions

29

Media (singular: Medium)

the food that is used to culture microorganisms

30

Physical Factors that affect Growth of Microorganisms:

1. Temperature - there is an optimum temperature for all living organisms to grow

2. pH - reflects the relative acidity/alkalinity of a solution (0 [most acidic] to 14 [most alkaline]) all living organisms have an optimum pH
- Human Blood has a pH of 7.2-7.4

3. Oxygen gas: only 50% of all microorganisms require oxygen
- In fact, even trace amounts of oxygen can be deadly to some microbes

4. Salt concentration: Controls the amount of water available to a cell (also the same with sugar)

31

Isotonic

Define: Solute concentration is the same outside & inside the cell

What happens: Stays the same

Why: Equilibrium already reached

32

Hypertonic

Define: Solute concentration greater outside the cell than inside the cell

What happens: Crenates (shrinks)

Why: water rushes out of the cell

33

Hypotonic

Define: Solute concentration less outside the cell than inside

What happens: Lysis (swells)

Why: water rushes into the cell

34

Types of media

1. Solid: Agar

2. Liquid: Broth

3. Semisolid: contains lower % of agar than solid media (bit runny)

35

Agar

an algal extract that acts as a solidifying ingredient when added to microbial media

  • no nutritional substance

the media is mixed , heated to boiling, & sterilized into an autoclave. Once sterile, molten media is put into sterile Petri dishes or test tubes.

36

Why not use gelatin instead of agar?

Gelatinized media turns to a liquid at 37* (room temperature) and agar does not. Aldo some organisms produce enzymes that turn gelatin into a liquid.

37

Most bacteria divide by a process called...

Binary fission

  • Binary - 2
  • Fision - to split
38

Generation time

the time it takes for a single cell to split into two new cells

39

When you start to see one little colony approximately how many cells need to be in the colony for you to be able to "see" it?

About 1 million

40

Descriptive terms for colonies grown on a solid surface

1. Whole colony shape
2.Margin (edge of the colony): Swarm - leaving an opaque pattern of waves across the medium (sometimes they do this)
3. Elevations: What the colony looks like from the side (how high off media
4. Size: measured in millimeter (mm) Punctiform- colonies of enormous size
5.Texture: wet, mucoid, erose (dry, crusty) granular, opaque (almost see through them), shiny, and dull
6. Pigment: may be within the colony or diffusing away from the colony

41

NA Agar

Bacterial

42

SDA agar

Fungal

43

Bacterial Configurations:

1 Round,
2 Round with scalloped margin,
3 Round with raised margin,
4 Wrinkled,
5 Concentric,
6 Irregular and spreding

44

Fungal Configurations

1 Filamentous,
2 L-Form (darker mass in middle)
3 Round with radiating margin
4 Filiform
5 Rhiziod
6 Complex

45

Bacterial Margins:

1. Smooth (entire)
2. Wavy (undulated)
3. Lobate
4. Irregular (erose)

46

Fungal Margins:

1. Ciliate
2. Branching
3. Wooly
4. Thread-like
5."Hair-Lock"-like

47

Bacterial Elevations:

1. flat
2. raised
3. convex
4. Drop-like

(5.) Umbonate ??

48

Fungal Elevations:

1. Hilly
2. Ingrowing into medium
3. Crateriform

(4.) Umbonate ??

49

Ring

Film of growth clinging to the test tube at the liquid-air interface

50

Pellicle

A membrane or scum-like structure that floats on the top of the liquid media

51

Sediment

Organisms may settle and grow, forming a layer at the bottom of the tube.

52

Folcculent

Visible chunks/flakes/broken particles supended throughout the broth medium

53

Uniform Fine Tubridity

Turbidity means "cloudy"

54

Why might an organism fail to grow?

bad culture, loop was too hot when trying to transfer, or the nutrients weren't right for the the organism

55

Why might two different organisms show exactly the same growth features even if they are not supposed to?

Cross contamination

56

Why is it necessary to use a negative control?

It make it easier for a base-line comparison

57

What is meniscus?

When water beads or pools up on a surface

58

what growth patterns are similar or different among the organisms tested?

Bacillus subtilius - Pellicle (the only one that had it)

Everything had sediment

59

Is it possible for an organism to produce more than one growth pattern in the same tube?

Yes

60

A film of growth on teh surface:

Pellicle

61

Even cloudiness

Uniform fine turbidity

62

Growth adhering to the glass at the liquid/air interface:

ring

63

Suspended flakes or particles:

Flocculent

64

A layer of growth at the bottom of the broth

Sediment

65
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#A is the Ocular

66
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#B is the rotating nosepiece

67
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# 3, 4, 5 are the objectives

68
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#11 is the mechanical stage

69
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#I is the stage adjustment knobs

70
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#8 is the Substage light

71
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#14 is the Base

72
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#10 is the Arm

73
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#G is the Coarse adjustment knob

74
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#H is the Fine adjustment knob

75
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#K is the power switch

76
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#7 Condenser

  • Connected to the condenser is the iris diaphragm lever which controls the light that filters through
77

Working distance

The distance between the slide and the objective lens

78

Calculating total magnification:

Ocular 10X 10X 10X 10X
Objective (4X) (10X) (40X) (100X)
Total: 40X 100X 400X 1000X

79

Refraction:

The bending of light as it passes from one medium to the next

  • The amount of available light decreases w/ magnification because the field of view becomes smaller and smaller
  • At 1000X, there is not enough light available to see the specimen clearly w/o the use of immersion oil. Therefore, immersion oil must be used w/ the 100X objective
80

what happens to the field of view as the magnification increases?

it decreases

81

What happens to the light when the iris diaphragm lever is moved to the left (increases or decreases)? Moved to the right (increases or decreases)?

Increases, Decreaes

82

What happens to the contrast when the iris diaphragm lever is moved the left (increases or decreases)? Moved to the right (increases or decreases)?

Decreases, Increases

83

True/False:

The Coarse adjustment knob may be used with all 4 objective lenses.

False

84

True/False:

The fine adjustment knob may be used with all 4 objective lenses

True

85

What part of the microscope should be used to center the speciment in the field of view?

Stage adjustment knobs

86

What part of the microscope can be adjustment to increase or decrease the contrast?

iris diaphragm lever

87

True/False:

Immersion oil helps to increase the refraction of light as it passes through the glass specimen slide

False

88

If the power of the ocular is 5X and the total magnification is 200X, what is the power f the objective? Justify your answer by showing your work.

200/5 = 40

40X

89

If the power of the ovular is 10X and the power of the objective lens is 45X, what is the total magnification? Justify your answer by showing your work

45X*10X=450X