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Infectious Agents > Exam 1: Bacterial Classification and Morphology > Flashcards

Exam 1: Bacterial Classification and Morphology Flashcards

1
Q

What are eukaryotic organisms?

A

True nucleus

Includes all organisms, microscopic and macroscopic, except bacteria and blue green algae

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2
Q

What are prokaryotic organisms?

A

Before nucleus

Simpler cell types, 0.3 to 2.0 μm in diameter

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3
Q

Describe the difference between prokaryotic and eukaryotic cells for nuclear membrane

A

Prokaryotic cells: Absent

Eukaryotic cells: Present

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4
Q

Describe the difference between prokaryotic and eukaryotic cells for nucleolus

A

Prokaryotic: Absent
Eukaryotic: Present

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5
Q

Describe the difference between prokaryotic and eukaryotic cells for chromosome number

A

Prokaryotic: 1 usually
Eukaryotic: More than 1

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6
Q

Describe the difference between prokaryotic and eukaryotic cells for chromosomal structure

A

Prokaryotic: Supercoiling, no histones
Eukaryotic: Histones

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7
Q

Describe the difference between prokaryotic and eukaryotic cells for ploidy

A

Prokaryotic: Haploid
Eukaryotic: Diploid

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8
Q

Describe the difference between prokaryotic and eukaryotic cells for reproduction

A

Prokaryotic: Asexual
Eukaryotic: Sexual and asexual

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9
Q

Describe the difference between prokaryotic and eukaryotic cells for mitotic nuclear division

A

Prokaryotic: Absent
Eukaryotic: Present

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10
Q

Describe the difference between prokaryotic and eukaryotic cells for cell wall with nurein

A

Prokayotic: Present
Eukaryotic: Absent

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11
Q

Describe the difference between prokaryotic and eukaryotic cells for cytoplasmic ribosomes

A

Prokaryotic: 70S
Eukaryotic: 80S

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12
Q

Describe the difference between prokaryotic and eukaryotic cells for cytoskeleton

A

Prokaryotic: Absent
Eukaryotic: Present

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13
Q

Describe the difference between prokaryotic and eukaryotic cells for microtubules

A

Prokaryotic: Absent
Eukaryotic: Present

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14
Q

Describe the difference between prokaryotic and eukaryotic cells for endoplasmic reticulum

A

Prokaryotic: Absent
Eukaryotic: Present

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15
Q

Describe the difference between prokaryotic and eukaryotic cells for lysosomes

A

Prokaryotic: Absent
Eukaryotic: Present

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16
Q

Describe the difference between prokaryotic and eukaryotic cells for mitochondria

A

Prokaryotic: Absent
Eukaryotic: Present

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17
Q

Describe the difference between prokaryotic and eukaryotic cells for chloroplasts

A

Prokaryotic: Absent
Eukaryotic: Present (plant cells)

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18
Q

Describe the difference between prokaryotic and eukaryotic cells for golgi apparatus

A

Prokaryotic: Absent
Eukaryotic: Present

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19
Q

Describe the difference between prokaryotic and eukaryotic cells for electron transport

A

Prokaryotic: cytoplasmic membrane
Eukaryotic: mitochondrial membrane

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20
Q

Describe the difference between prokaryotic and eukaryotic cells for cytoplasmic membrane

A

Prokaryotic: Sterols generally absent
Eukaryotic: Sterols present

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21
Q

Why are the differences between prokaryotes and eukaryotes important?

A

The differences reveal their different strategies for survival
The differences allow antimicrobials targeting unique bacterial structures

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22
Q

What is the strategy of survival for eukaryotes?

A

Adaptation and specialization

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23
Q

What is the strategy of survival for prokaryotes?

A

Divide and conquer

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24
Q

How are fungi like bacteria?

A

Their structural complexity does not include differentiation into specialized tissues and organs

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25
Q

What is the system by which bacteria are named?

A

Bacterial nomenclature

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26
Q

How is the classical binomial Linnean system used?

A

Each distinct kind is given a species and genus name
A number of species ma be included in a genus
The first word is the genus name and is always capitalized
Both the genus and species names are italicized

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27
Q

What is taxonomy?

A

System of classification that groups bacteria with similar properties and is used to distinguish those that are different

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28
Q

What is the basic taxonomic unit in bacteria?

A

Species

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29
Q

What is a species defined as in prokaryotes?

A

A group of strains with unique phenotypic properties and exhibit more than 70% whole genome DNA-DNA hybridization among strains

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30
Q

What does a bacterial strain consist of?

A

The descendants from a single isolate in pure culture

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31
Q

What is a type strain?

A

The originally described isolate of the species

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32
Q

What is the modern system of classification that is now used?

A

Polyphasic taxonomy

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33
Q

What does polyphasic taxonomy use?

A

The combines systems of DNA sequence and phenotypic characteristics

34
Q

What are the different methods of DNA sequence?

A

DNA-DNA hybridization (70%)
16S rRNA sequence (97%)
Multilocus sequence typing
Average nucleotide identity (95%)

35
Q

What are the phenotypic characteristics looked at for polyphasic taxonomy?

A 
Chemical analyses of structural components
Serologic reactivity 
Enzyme profile
Nutritional requirements
Morphology
36
Q

What are the accepted phylogenetic classifications of bacteria?

A

Bergey’s Manual of Systematic Bacteriology

The National Center for Biotechnology Information

37
Q

What are keys used to do?

A

Classify bacteria into convenient groups of clinical interest

38
Q

What are the 3 domains in the tree of life?

A

Archaebacteria
Eubacteria
Eukaryota

39
Q

How can eubacteria be divided?

A

Cell envelope type

Cell morphology

40
Q

What are the cell envelope types?

A

Gram-positive

Gram-negative

41
Q

What are the 3 basic cell types?

A

Cocci (spherical)
Bacilli (cylindrical/rods)
Spirilla (helical, spiral, or curved)

42
Q

What allows bacteria to be motile?

A

Flagella
Corkscrew
Gliding

43
Q

What are the methods of multiplication?

A

Binary fission

Budding

44
Q

What is binary fission?

A

Once cell splits into 2 of slightly smaller size, no mitosis or meiosis

45
Q

What are the types of cell association?

A

Long chains
Clusters
Cubical packets of 4 or 8
Pairs

46
Q

What bacteria are in long chains?

A

Streptococci

47
Q

What bacteria are in clusters?

A

Staphylococci

48
Q

What is the dependence on living cells for growth?

A

Some are capable of independent growth on lifeless artificial media
Some require living cells from growth, especially obligate intracellular parasites

49
Q

What are the different atmospheric requirements?

A 
Obligate aerobes
Obligate anaerobes
Facultative anaerobes
Microaerophilic
Aerotolerant
Capnophilic
50
Q

What are obligate aerobes?

A

Require oxygen, oxidize only, respire

51
Q

What are obligate anaerobes?

A

Killed by oxygen, ferment only or use anaerobic respiration

52
Q

What are facultative anaerobes?

A

Go either way, oxidize or ferment, prefers growing with oxygen

53
Q

What are microaerophilic?

A

Require reduced oxygen

54
Q

What are aerotolerant?

A

Do not require oxygen, not killed by oxygen, ferment only

55
Q

What are capnophilic?

A

Require increased carbon dioxide

56
Q

What are the most common units of measurement in microscopy?

A

The micron/micrometer (10-6) and the nanometer (10-9)

57
Q

What is the maximum resolving power of a light microscope?

A

0.2 μm under optimal conditions

58
Q

What magnification is commonly used with oil immersion lens?

59
Q

What is darkfield and phase contrast microscopy?

A

Resolution to 0.1 μm

Used to observe unstained, living cells and movement

60
Q

What is fluorescent microscopy?

A

Resolution to 0.1 μm

Used in research and diagnostic labs; immunofluorescence

61
Q

What is electron/scanning and transmission microscopy?

A

Resolution to 0.0003 μm (0.3 nm)

Internal or surface detail observable

62
Q

How can you observe transparent cells?

A

Staining procedures

63
Q

What is the preparation for staining?

A

A drop of liquid containing bacteria is placed on a glass slide and allowed to dry
The dried film is “fixed” onto the slide using a chemical fixative or heat
Stains are used that preferentially stain specific cell components

64
Q

What does passing the slide through a flame do?

A

Coagulates the cell surface protein and sticks the bacteria to the slide

65
Q

What are the different types of stains?

A

Positive
Negative
Differential

66
Q

Describe positive stains

A

Have an affinity for one or more cell components

The simplest stains are colored cationic salts that combine with phosphate groups of nucleic acids

67
Q

What is an examples of a positive stain?

A

Methylene blue

68
Q

What are negative stains?

A

Acidic dyes that do not penetrate cells

The background contrasts with cells

69
Q

What is an example of negative stains?

70
Q

What are differential stains used to do?

A

Separate bacteria into groups based on their ability to take up and retain certain dyes

71
Q

What are examples of differential stains?

A

Gram stain and acid fast stain

72
Q

What is the gram stain?

A

The most widely used differential stain to divide all eubacteria into 2 groups

73
Q

What is the procedure for gram stain?

A

Primary stain
Mordant
Decolorizer
Counterstain

74
Q

Describe the primary stain step of gram stain

A

Gentian or crystal violet is a basic purple dye used
All bacteria able to take it up are stained purple
It is applied for 45-60 seconds and gently rinsed off with tap water

75
Q

Describe the mordant step of gram stain

A

Gram’s iodine is added to the slide and incubated for 45-60 second
It complexes with crystal violet and decreases solubility
Rinse gently

76
Q

Describe the decolorizer step of gram stain

A

Ethyl alochol +/- 10% acetone is dripped over the smear in a controlled fashion for 5-7 seconds
Rinse gently to stop decolorization
This is the most important step

77
Q

Describe the counterstain step of gram stain

A

Safranin is contrasting red dye that is applied for 45-60 seconds
Rinse gnetly

78
Q

How can you tell if a bacteria is gram positive?

A

It will retain the purple dye and resist decolorization

79
Q

How can you tell if a bacteria is gram negative?

A

Bacteria that were decolorized will take up the counterstain and appear pink or red

80
Q

What is gram’ stain used to determine?

A

Gram’s reaction
Arrangement (spatial orientation resulting as a consequence of growth)
Morphology (form of cells)

81
Q

What is a simple test for determining gram reaction of bacteria without staining?

A

Add a colony to a drop of 10% KOH on a glass slide and stir
If solution becomes soapy, bacteria are gram-negative
The reaction is caused by saponification of phospholipids in the outer membrane

82
Q

Look at pictures in PowerPoint

A

Look at pictures in PowerPoint

Infectious Agents (38 decks)

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