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Microbio > Lectures 1 and 2 > Flashcards

Lectures 1 and 2 Flashcards

1
Q

Study of Microbes

A
  • all microbes are NOT bad
  • humans are more microbe than human cells (3-5 lbs)
    • 200 species in mouth
    • 100 in gut
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2
Q

Microbial Taxonomy: Archaea

A

3 established phyla

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3
Q

Microbial Taxonomy: Protista

A

supergroups

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4
Q

Microbial Taxonomy: Fungi

A

6 fungal phyla

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5
Q

Pathogenicity

A
  • host-parasite relationships
  • pathogen transmission
  • exotoxins, endotoxins
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6
Q

members of the microbial world

A
  • organisms and acellular entities too small to be clearly seen by the unaided eye
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7
Q

members of the microbial world: cellular
(list 4 types)

A
  1. fungi
  2. protists
  3. bacteria
  4. archaea
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8
Q

fungi: examples

A
  1. yeast
  2. mold
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9
Q

Protists: examples

A
  1. algae
  2. slime molds
  3. protozoa
  4. triconympha
    5.dinenympha
  5. amoeba
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10
Q

Bacteria: examples

A
  1. Bacillus anthracis
  2. staphylococcus aureas
  3. e.coli
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11
Q

Archaea: examples

A
  1. methanogens
  2. halo archaea
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12
Q

Members of the microbial world: acellular
(list 4 types)

A
  1. viruses
  2. viroids
  3. satellites
  4. prions
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13
Q

viruses: makeup and examples

A

made of protein and nucleic acid (can be RNA, DNA variants)
1. covid
2. influenza
3. rhinovirus

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14
Q

viroids: makeup and example

A

made of RNA
1. plant pathogen

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15
Q

satellites: makeup and examples

A
  • made of nucleic acid enclosed in a protein shell
  • require a helper virus
    1. Hep. D
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16
Q

Prions: makeup and examples

A

made of proteins
1. mad cow disease
2. CJD

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17
Q

Types of microbial cells: 3 domain system

A

bacteria, archaea, eukaryotes

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18
Q

Bacteria and Archaea: distinctions from eukaryotes

A
  • smaller
  • have a nucleoid region
  • only microbes
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19
Q

Eukaryotes: distinction from bacteria and archaea

A
  • have a nucleus
  • larger
  • have organelles in cytosol (make up cytoplasm)
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20
Q

Similarities between bacteria, archaea, and eukaryotes

A
  • all have ribosomes, cytoplasm, and a plasma membrane
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21
Q

Nomenclature

A

genus, species, strain

example:
E. Coli 0157:H7
E = genus
coli = species
0157.H7 = strain

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22
Q

Domain characteristics: bacteria

A
  • peptidoglycan
  • usually single-celled
  • most lack a membrane-bound nucleus
  • ubiquitous, can live in extreme environments
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23
Q

domain characteristics: archaea

A
  • lack peptidoglycan
  • unique membrane lipids
  • unusual metabolic characteristics
  • many live in extreme environments
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24
Q

domain characteristics: eukaryotes

A
  • membrane bound organelles
  • linear DNA
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25
Q

Robert Hooke

A
  • published first drawings of microbes
    • Micrographia book w/ detailed drawings of fungus and other microorganisms
  • bent glass to magnify and view things (idea of a microscope)
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26
Q

Antony Van Leeuwenhoex

A
  • constructed simple microscopes
  • looked at pond water, blood, feces, etc.
  • “animalcules:” first word for microbes
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27
Q

Francesco Redi

A
  • discounted spontaneous generation theory (living organisms can develop or arise from nonliving/decomposing matter)
  • proved that maggots on decaying meat came from fly eggs, not the meat itself
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28
Q

Louis Pasteur

A
  • disproved spontaneous generation in microbes
  • pasteurization (heating to kill pathogens)
  • rabies and anthrax vaccines
  • swan flask (neck traps airborne microbes at base so solution is sterile)
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29
Q

Edward Jenner

A
  • pioneer of smallpox vaccine
    • used cowpox: took sample and inserted it into 8 y/o boy’s arm
    • later he was exposed to smallpox and was fine
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30
Q

Robert Koch

A
  • anthrax and tuberculosis
  • postulates: established link between pathogen and disease
31
Q

development of techniques for studying microbial pathogens
(3 scientists and their creations/discoveries)

A

Hesse: nutrient agar
Petri: petri dish
Chamberland: bacterial filter and autoclave

32
Q

Dmitri Ivanovsky

A
  • discovered viruses
  • studied disease in tobacco plants, leading to discovery
    • crushed infected leaves and forced through bacterial filter but found nothing
    • brushed on other leaves which caused disease
    • figured pathogen must be smaller than bacteria
33
Q

Martinus Beijerinck

A
  • coined term “virus”
34
Q

Alexander Fleming

A
  • realized his body had its own antibacterial power
    • nasal mucus
    • lysozyme
  • 1928 vacation
    • bacteria killed by mold (penicillin)
    • was unable to purify and concentrate the substance
    • in 1940, Florey and Chain purified it, the three of them shared Nobel prize in 1945
35
Q

Preparation and staining of specimens: purpose

A
  • increases visibility of specimen
  • accentuates specific features
  • preserves specimen
36
Q

prep and staining: fixation

A

preserves internal and external structures and fixes them in position
- heat fixation (overall morphology)
- chemical fixation (protects fine cellular substructure and morphology)

37
Q

prep and staining: dyes and simple staining

A

one dye
- divides microorganisms based on their staining properties
- detects presence or absence of structures
- endospores

38
Q

gram staining (differential)

A
  • widely used differential staining procedure
  • divides into gram positive and gram negative
  • based on differences in cell wall structure, depends on peptidoglycan layer
39
Q

4 steps of preparation and staining

A
  1. fix cells. crystal violet (primary stain) for one minute. water rinse. results in purple stain
  2. Iodine for 1 minute. water rinse. results in purple staying
  3. alcohol (decolorizer) for 10ish seconds. gram positive is purple, gram negative is colorless
  4. safranin (counterstain) for 30-60 seconds. water rinse, blot dry. gram positive stays purple, gram negative is red
40
Q

staining specific structures

A
  1. endospore: double-staining technique
  2. capsule staining: 1 negative stain
  3. flagella staining: increases thickness of flagella
41
Q

Light microscope varieties

A
  • bright-field
  • dark-field
  • phase-contrast
  • fluorescence
  • confocal
42
Q

compound microscope features

A

2 sets of lenses
- ocular
- objective

43
Q

Bright-field microscope

A
  • dark image against bright background
  • several objective lenses
  • ideally parfocal
  • total magnification
44
Q

parfocal

A
  • when objective is changed, image stays in focus
  • ideal, extremely hard to achieve
45
Q

dark-field microscope

A
  • bright image against dark background
  • uses a dark stop placed inside condenser, blocks light from shining directly through onto field
  • detailed images of unpigmented specimen
  • limits: lose magnification, can look grainy
46
Q

phase-contrast

A
  • converts slight variations in cell density into changes in light intensity
  • colorless unstained cells are visible
  • limits: can create a false halo around specimes
47
Q

Differential Interference Contrast

A
  • similar to phase contrast
  • used to observe living cells
  • unstained appears colorful, 3D, no halo
48
Q

Fluorescence

A
  • exposes specimen to UV, violent, or blue light
  • fluorochromes (dyes)
    • ex: staining alive and dead bacteria in different colors
    • ex: tagging pathogens
49
Q

electron microscopy: how it works

A
  • electrons replace light as illuminating beam
  • allows for study of microbial morphology in great detail (can see viruses)
50
Q

electron microscopy: types

A
  • transmission electron microscopy (TEM)
  • scanning electron microscopy (SEM)
51
Q

transmission electron microscopy (TEM)

A
  • electron gun passes electrons through sample (sample must be thin)
  • denser regions appear darker
  • limitations: takes a long time to process
52
Q

scanning electron microscopy

A
  • electrons reflected from surface of specimen
  • realistic 3D image of surface features
53
Q

bacteria: 5 shapes

A
  • cocci
  • bacilli
  • vibrio
  • spirillum
  • spirochete
54
Q

cocci: arrangements

A
  • diplococci: 2 attached
  • streptococci: chains
  • staphylococci: clusters
  • tetrad: 4 on perpendicular plane, like a square
  • sarcina: 2 tetrads together
55
Q

bacilli (rods)

A
  • single
  • sporeformer (spore at one end)
  • streptobacillus: chains
  • coccobacillus: squished cocci
56
Q

vibrio

A

comma shaped

57
Q

spirillum

A

rigid, external flagella at one or both ends

58
Q

spirochete

A

flexible, endoflagellum

59
Q

bacteria size: average rod

A

1.5 microns x 6 microns
roughly size of e.coli

60
Q

smallest bacteria

A

mycoplasma
0.3 microns

61
Q

largest bacteria

A
  • discovered in June 2022
  • thiomargarita magnifica
  • 1 cm long
62
Q

large bacteria

A

e. fishelsoni
600 microns

63
Q

bacterial cell structure: organization

A
  • cell envelope
  • cytoplasm
  • external features
64
Q

cell envelope: plasma membrane

A
  • encompasses cytoplasm
  • selectively permeable barrier
  • interacts with external environment
    • nutrients in, waste out
    • transport systems
    • metabolic processes (electron transport chain)
65
Q

fluid mosaic model

A
  • lipid bilayer with floating proteins
  • amphipathic lipids
    • polar (hydrophilic) heads
    • nonpolar (hydrophobic) tails
  • proteins
66
Q

membranes: characteristics

A
  • lack sterols, but have sterol-like molecules
    • hopanoids (stabilize cell wall)
67
Q

cell wall: functions

A
  • maintains shape of bacterium
  • protects cell from osmotic lysis
  • protects from pathogens
68
Q

peptidoglycan structure

A
  • meshlike polymer
  • 2 alternating sugars (NAG & NAM)
  • amino acid side chains on NAM
69
Q

gram positive cell wall

A
  • peptidoglycan with teichoic acids
  • periplasmic space (narrow, mostly water)
  • plasma membrane
70
Q

gram negative cell wall

A
  • 2 periplasmic spaces
  • outer membrane
  • peptidoglycan
  • plasma membrane
71
Q

gram negative cell outer membrane

A
  • lipopolysaccharides
  • porins (let water in)
  • Braun’s lipoprotein
  • outer membrane receptor
72
Q

Braun’s lipoprotein

A
  • attach peptidoglycan to outer membrane
73
Q

lipopolysaccharides: parts and functions

A
  • lipid a (endotoxin)
  • core polysaccharide
  • o side chain
  • provides stability and protection
  • can be pathogenic

Microbio (11 decks)

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