Microbiology

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1

Capsule

A distinct, thick gelatinous material that surrounds some microorganisms

2

Chemotaxis

Movement of a cell toward or away from certain a chemical in the environment

3

Cytoplasmic membrane

A phospholipid bilayer embedded with proteins that surrounds the cytoplasm and defines the boundary of the cell

4

Endospore

An extraordinary li resistant dominant cell produced by some types of bacteria

5

Flagellum

A type of structure used for cell movement

6

Gram-negative bacteria

bacteria that have a cell wall characterized by a thin layer of Peptidoglycan surrounded by an outer membrane, when Gram stained, the cells are pink

7

Gram positive bacteria

Bacteria that have a cell wall characterized by a thick layer of peptidoglycan, when Gram stain, these cells are purple

8

Lipopolysaccharide (LPS)

Molecule that makes up the outer layer of the outer membrane of gram-negative bacteria

9

Peptidoglycan

A macromolecule that provides strength to the cell wall, it is found only in bacteria

10

Periplasm

the gel-like material that fills the region between the cytoplasmic membrane and the outer membrane of gram-negative bacteria

11

Pili

cell surface structures that allow cells to adhere to certain material, some types are involved in a mechanism of DNA transfer

12

Plasmid

Extrachromosomal DNA molecule that replicates independently of the chromosome

13

Ribosome

Structure involved in protein synthesis

14

Transport systems

Mechanism cells use to transport nutrients and other small molecules across the cytoplasmic membrane

15

What two fundamental cell types did microscopic study reveal

Prokaryotic and eukaryotic

16

All the domains of bacteria and archaea are what type of cell?

Prokaryotic

17

Cells of all animals, plants, protozoa, fungi and algae are what type of cell?

Eukaryotic

18

Prokaryotic cells

-Smaller

.easier for them to take in nutrients and excrete waste products

-vulnerable to threats

.predators.

.parasites

.competitors

-unique features

.increase chance of survival

19

Eukaryotic cells

-more complex

-larger

-cell processes take place within membrane-bound compartments

-nucleus

20

Light microscope

-Uses visible light and a series of lenses to magnify objects

-easy to use

-can magnify images 1000 X

-routinely used

-observe

.cell size

.shape

.motility

21

Electron microscope

-magnifies images 100, 000X

-fine details of cell structures

22

What is the most common type of light microscope?

Bright-field microscope

23

What does a brightfield microscope do?

Evenly illuminates a field of view and generates a bright background

24

Call the modern light microscope

Compound microscope

25

Objective lens

Series of lenses house in a tube immediately above the object being viewed

26

Ocular lens (eyepiece)

Close to the eye

27

What's your lenses are used in combination?

Objective and ocular lens

28

Most compound microscopes have a selection of objective lenses that are powers of?

4x, 10x, 40x, and 100x

29

Condenser lens

Positioned between the light source and the specimen, does not magnify but focuses the light on the specimen.

30

Resolving power

-Determines how much detail can be seen in the observe specimen

-measure of the ability to distinguish two objects that are very close together

31

The resolving power of a microscope depends on?

-Quality of lens

-type of lens

-wavelength of the light

-magnification

-specimen preparation

32

At 0.2 micrometers you can see the morphology of ____________ but you cannot distinguish the size of__________.

-prokaryotic cell

-viruses

33

Super-resolution microscopes

Resolution up to 10 nm

34

In order to obtain maximum resolution when using certain high power objective such as the 100x lens ___________ must be used to displace ________________.

-Immersion and oil

-displace are between lens and specimen

35

Refraction

Bending of light rays that occurs when light passes from glass to air

36

How do we prevent refraction in using high power objectives

Oil immersion of the lens

37

Light microscopes include?

Bright-field

dark field

phase-contrast

differential interference contrast

fluorescent scanning laser

super resolution

38

Brightfield (light microscope)

-Illuminates an even field of view

-generatesa bright background

-most common

39

Dark field (light microscope)

-latest directed towards specimen at an angle

-unstained cells easier to see

-organism stand out as bright objects against dark background

40

Phase contrast (light microscope)

-increases contrast by amplifying differences in refractive index

-dense material appears darker than normal

41

Differential interference contrast (light microscope)

-two light beams pass through specimen and recombined

-specimen appears three-dimensional

42

Fluorescence (light microscope)

-projects ultraviolet light causing fluorescent molecules to emit longer wave length light

-observes cells stained or tagged with fluorescent dye

43

Scanning laser (light microscope)

-mirror skin laser beam across successive regions and planes of specimen from that information a computer constructs an image

-obtains three-dimensional image of structure that has been stained with fluorescent dye

-detailed sectional views of intact cells

44

Super resolution (light microscope)

-complex elimination mechanisms and merge data construct image

-higher resolving power than conventional fluorescence microscope

45

Electron microscopes include?

-Transmission

-scanning

46

Transmission (electron microscope)

-Transmits a beam of electrons through specimen

-complicated specimen preparation required

47

Scanning (electron microscope)

-Beam of electrons scans back and forth over surface of specimen

-used to observe surface details

-produces three-dimensional effect

48

Atomic Force(Scanning probe microscope)

-pro moves in response to events latest force between it in the sample

-no special sample preparation required

-produces three-dimensional effect

49

What cannot be used to observe living cells because it kills them?

Staining process

50

Wet mount

-easiest way to microscopically examining specimen

-observe living microorganisms

-consists of drop of liquid specimen and coverslip

51

Simple staining

Only single dye is used to stain specimen

52

Basic dyes include

- methylene blue

-Crystal violet

-safranin

-malachite green

53

Negative staining

Procedure that colors the background

54

What type of dyes are used in negative staining?

Acidic dyes

55

Differential staining

multi stop procedure used to stain cells and distinguish one group of microorganisms from another

56

Two most frequently used differential staining techniques?

- Gram stain

- acid-fast stain

57

Gram stain

-Used to separate bacteria into two groups

.gram-positive

.gram-negative

-reflects the difference in structure of cell walls

--most common

58

Acid-fast stain

-used to detect organisms that do not easily take up stains

ex. Mycobacterium

59

Special stains

Used to stain specific cell structures

60

Capsule stain

-darkens background

-stands out as a clear area surrounding cell

61

Endospore stain

Stains a type of dormant cell that does not readily take up stains, produced by bacillus and clostridium species

62

Flagella stain

Staining agent that adheres to and coats then flagella

63

Fluorescent dyes and tags

Absorb ultraviolet light, then emit light of longer wavelength

64

Fluorescent dyes

Some Vines you compounds found in all cells, others buying two compounds specific only to certain types of cells

65

Fluorescent tags

Antibodies to which a fluorescent molecule has been attached are used to tag specific molecules

66

Decolorizing agent

95% alcohol, removes dye-iodine complex from gram-negative but not gram-positive bacteria.

67

Counterstain

Applied to give different color to now colorless gram-negative bacteria, red safranin commonly used

68

Gram staining is more reliable?

Less than 24 hours old

69

Immunofluorescence

Use the tag specific cell components with fluorescent dye attached to an antibody

70

What two general shapes are most common bacteria?

Spherical (coccus)

cylindrical (rod)

71

What is the difference between Bacillus and bacillus?

B= Genus

b= species

72

A rod so short that it might be mistaken for a coccus is called?

Coccobacillus

73

Rod-shaped bacteria that is not bacillus?

Escherichia coli

74

vibro

Type of cell with a short curved rod

75

Spirillum

Cell with a curved Long rod enough to form spirals

76

Spirochete

Long spiral shape cell with a flexible cell wall and a unique mechanism of motility

77

Pleomorphic

Bacteria that characteristically vary in their shape

78

Greatest diversity of cell shapes is found in?

Low nutrient aquatic environments

79

Summit aquatic bacteria have _______ giving them a star like appearance?

Cytoplasmic extensions

80

Cells found in low nutrient aquatic environments have a large surface area that helps them to?

Absorb nutrients

81

Archaeal cells that have been found in salt ponds have a _________ appearance?

Square, tile like

82

Binary fission

Process where one cell divides into two

83

Cells often stick to each other following division, forming _______ _______?

Characteristic arrangements

84

Diplococci

Cocci that typically occur in pairs

85

An important clue in the identification of neisseria gonorrhea is its characteristic?

Diplococcus arrangement

86

Cells like streptococcus form?

Long chains

87

Strepto means?

Twisted chain

88

Most prokaryotes divide by?

Binary fission

89

The cell envelope of the prokaryotic cell consist of?

-cytoplasmic membrane

-cell wall

-capsule (if present)

90

Cell envelope of a prokaryotic cell?

Surface layers of a prokaryotic cell

91

Enclosed within the envelope of the prokaryotic cell is?

Cytoplasm

92

Cytoplasm

Fix substance filled with nutrients ribosomes and enzymes fluid portion of which is called cytosol

93

Nucleoid

Joe lake region in cytoplasm where the cell's chromosome is found

94

Nucleoid is ____ enclosed by a membrane in a prokaryotic cell.

not

95

Filamentous appendages (prokaryote)

Composed of protein subunits that form a helical chain

96

Flagella (prokaryote)

Provide the most common mechanism of motility

97

Pili (prokaryote)

-Different types have different function

-common type fembriae

-allow cells to eat here to surfaces

-certain types used for twitching / gliding mobility

98

Sex pili involved in? (prokaryote)

DNA transfer

99

Capsule (prokaryote)

Distinct in gelatinous

allows bacteria to adhere to specific surfaces

allows some organisms to avoid body's defense systems causing disease

100

Slime layer (prokaryote)

-Diffuse / irregular

-allows bacteria to adhere to specific surfaces

101

What provides rigidity to the cell wall of a prokaryote that stops it from lysing?

Peptidoglycan

102

Gram positive (prokaryote)

Thick layer of peptidoglycan that contains teicholic acids and lipoteicholic acids.

103

Gram-negative (prokaryote)

Thin layer of peptidoglycan surrounded by an outer membrane (outer layer of membrane is lipopolysaccharide).

104

Cytoplasmic membrane (prokaryote)

-Phospholipid bilayer embedded with proteins

-surrounds cytoplasm

-separates from external environment

-transmits information about external environment to inside cell

105

DNA (prokaryote)

Carries genetic information of the cell

106

Chromosome (prokaryote)

-Carries the genetic information required by a cell

-single circular double stranded DNA molecule

-found in the nucleoid

107

Nucleoid (prokaryote)

irregularly-shaped region within the cell of a prokaryote that contains all or most of the genetic material. Not surrounded by a nuclear membrane.

108

Plasmid (prokaryote)

Generally carries only genetic information that may be advantageous to a cell in certain situations

109

Endospore (prokaryote)

Type of dormant cell that is extraordinary only resistant to heat, desiccation, ultraviolet light, and toxic chemicals.

110

Cytoskeleton (prokaryote)

Protein framework involved in cell division and control of cell shape.

111

Gas vesicles (prokaryote)

Small, rigid structures that provide buoyancy to a cell

112

Granules (prokaryote)

Accumulations of high - molecular - weight polymers, synthesized from a nutrient available in relative excess

113

Ribosomes

-Involved in protein synthesis

-two subunits (30S& 50S join to form the 70S ribosome)