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Microbiology > Microbiology Exam 1 > Flashcards

Microbiology Exam 1 Flashcards

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Biology 101 flashcards
1
Q

Define Prokaryotic

A

organisms without a true nucleus (on the other hand, eukaryotes have a true nucleus enclosed in a nuclear membrane)

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2
Q

Define Nosocomial Pathogen

A

organism which causes infection, originating from a hospital

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3
Q

Define Iatrogenic Pathogen

A

organism which causes infection that arises from health care intervention

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4
Q

Define Occasional Opportunistic Pathogen

A

an organsim which causes infection because of a weaken immune system

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5
Q

Define Normal Flora

A

the mixture of organisms regularly found at any anatomical site (the bacteria that naturally live in our body)

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6
Q

What are the benifits of Normal Flora?

A
  • prevents colonization of pathogens
  • antagonize other bacteria (prevents growth of potentially harmful bacteria)
  • stimulates the production of antibodies
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7
Q

What are the human responses to microbial invasion?

A
  • Phagocytosis
  • inflammation
  • immune response (T and B cells)
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8
Q

Microorganisms respond to human response with:

A
  • capsule formation- gelatinous material surrounding bacterial cell wall, can protect cell from phagocytosis. (considered a virulence factor)
  • enzyme production
  • toxin production
  • biofilm production- a microbial community that usually forms a slimy layer on the surface
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9
Q

Factors Influencing Microbial Growth

A
  • moisture (culture medium and incubators)
  • pH (culture medium)
  • temperature (incubators, most at 35-37 degrees C)
  • oxygen (atmosphere)
  • nutrition (culture medium)
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10
Q

Define Obligate Aerobe

A

Organisms which require oxygen to grow

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11
Q

Define Microaerophile

A

Organism which requires oxygen in low concentrations to grow

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12
Q

Define Obligate Anaerobe

A

organisms that grow in the absence of oxygen

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13
Q

Define Facultative Anaerobe

A

organisms which can grow with or without oxygen

  • growth rate is higher in the prescence of oxygen
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14
Q

Define Aerotolerant Anaerobe

A

organism which only grows anaerobically, but continues growing in the prescence of oxygen

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15
Q

Growth Phases

  • match the letter to the phase and explain
A

A. Lag- bacteria are adapting to environment, cannot divide but are preparing

B. Exponential Phase (or Log Phase)- period of cell dividing at a constant rate

C. Stationary Phase- occurs because something has limited growth (ex. depleation of an essential nutrient). New cell production = death of old cells

D. Death Phase- bacteria run out of nutrients an die

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16
Q

Define Selective Media

A

A culture medium designed to suppress the growth of unwanted microorganisms and encourage the growth of desired ones (ex. MacConkey)

  • physical conditions of the media can be adjusted (such as pH and temperature) for the growth of certain organisms
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17
Q

Define Nutritive Media

A

Medium which supports the growth of most organisms (ex. Blood Agar)

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18
Q

Define Differential Media

A

A solid culture media that makes it easier to distinguish colonies of the desired organism

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19
Q

What kind of agar is this?

Primary Ingredients?

Differential/Selective/ Enrichment/ Isolation?

Organisms?

Special Notes?

A

Agar: Chocolate Agar

Ingredients: 2% hemoglobin or IsoVitalex

Enrichment

Fastidious Organisms (Neiseria gonorrhoeae)

* essentially the same as sheep blood agar except the red blood cells are lysed which provides essential nutrients for fastidious organisms

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20
Q

What kind of agar is this?

Primary Ingredients?

Differential/Selective/ Enrichment/ Isolation?

Organisms?

Special Notes?

A

Agar: Blood Agar

Ingredients: 5% sheeps blood

Enrichment/Differential

Nonfastidious organism

Hemolysis (alpha, betam gamma)

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21
Q

What kind of agar is this?

Primary Ingredients?

Differential/Selective/ Enrichment/ Isolation?

Organisms?

Special Notes?

A

Agar: Phenylethyl alchohol (PEA)

Ingredients: nutrients

Selective, Isolation

Aerobic gram positive

Anaerobic gram negative bacilli and gram positive cocci

  • inhibits gram negative organisms
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22
Q

What kind of agar is this?

Primary Ingredients?

Differential/Selective/ Enrichment/ Isolation?

Organisms?

Special Notes?

A

Agar: MacConkey

Ingredients: peptose base with lactose, crystal violet, bile salts, pH indicator

Selective, Differential, and Isolation

Enteric Bacilli

Seperates organisms based on lactose fermentation

Inhibits Gram positive organisms

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23
Q

Which bacteria are lactose + and which are lactose negative?

A

The baceria on the left are lactose positive because the colonies are pink

The bacteria on the right are lactose negative because the colonies are clear/white

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24
Q

What type of hemolysis is this?

Explain why

A

Alpha hemolysis on blood agar

Blood cells are only partially lysed and produce a greenish color around the colony

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25
Q

What kind of hemolysis is this?

Explain why

A

Beta hemolysis on blood agar

Blood cells are completly lysed around the colony.

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26
Q

What kind of hemolysis is this?

Explain why

A

Gamma hemolysis on blood agar

There was no lysing of red blood cells

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27
Q

What is the purpose of Thioglycollate Broth and Schaedlers Agar?

What are the ingredients?

A

To grown anaerobic bacteria

pancreatic digestion of casein, soy broth, and glucose

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28
Q

Define Colonization

A

microbial organisms living in concert either harmlessly, symbiotically, or harmfully with a human host

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29
Q

Define Disinfection

A

using an agent to destroy or inhibit microorganisms that may cause disease (but not there spores)

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30
Q

Define Fomite

A

any inanimate object that may be contaminated with disease causing microorganisms and can therefore serve to transmit disease

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31
Q

Define Isolation

A

preparing a microorganism specimen in such a way as to grow a colony from a single species for further identification or study

32
Q

Define Propagation

A

growth or spread of microorganisms

33
Q

Define Reservoir

A

The origin of the etiological agent or laction from which it dimmeminates (ex. water, food, insects, animals, other humans)

34
Q

Define Sterilization

A

a process by which all forms of microbial life and bacterial spores are killed

35
Q

Define Endotoxin

A

a component of gram negative bacterial cellular structure which can have devistating effects on the body’s metobolism, released when cells are destroyed

36
Q

Define Exotoxin

A

common to gram positive bacteria, produced and released by living cells. Target specific hosts.

37
Q

Define Vector

A

Any living organism that transmitts an etiological agent.

38
Q

Define Virulence Factor

A

factors which increase the degree of pathogenicity or disease- producing abiltiys of microorganisms.

39
Q

List Common Ways to Classify Bacteria

A

gram stain

morphology

biochemical characteristics

site of clinical recovery

antimicrobial susceptibility

40
Q

List the Steps of the Gram Stain

A

fix microorganism to slide

  1. Crystal violet: primary stain
  2. Grams Iodine: mordent
  3. Wash (alcohol, acetone): decolorizor
  4. Saffranin: safranin
41
Q

The pink organisms are_______ Gram +/-.

The purple/blue organism are________ Gram +/-.

A

Pink: Gram negative

Purple/blue: Gram positive

42
Q

Gram Stain and Morphology

A

Gram negative rod

ex. Escherechia coli

43
Q

Gram Stain and Morphology

A

Gram positive cocci

ex. Staphylococcus aureus

44
Q

Gram Stain and Morphology

A

Gram negatice cocci

ex. Neisseria gonorrhoeae

45
Q

Which type of bacteria ferment lactose?

Example?

A

gram negative rods

E. coli

46
Q

Which gram negative organism DOES NOT ferment glucose or other sugars?

A

Pseudomonas aeruginosa

47
Q

Give an example of a gram positive cocci that produces catalase.

A

Staphylococcus

48
Q

Give an example of a bacteria that produces the enzyme coagulase.

A

Staphylococcus aureus

49
Q

Give an example of a gram negative cocci that produces the enzyme oxidase.

A

Neisseria species

50
Q

Are organisms recovered from blood and CSF clinically significant?

A

Yes

51
Q

Is S. aureus recovered from respiratory specimens clinically significant?

A

No

52
Q

Is S. aureaus recoved from a wound clinically significant?

A

Yes

53
Q

Is E.coli recovered from a stool culture clinically significant?

A

No

54
Q

Is E. coli recovered from urine or blood clinically significant?

A

Yes

55
Q

What is happening in this picture?

A

Antimicrobial suceptibility- tests for bacterial sensitivity to antibiotics.

  • should always be performed on pure culture
  • certain organisms can be classified according to their susceptibility profiles
  • Ex. Methicillin resistant S. aureus (MRSA)
  • Vancomycin resistant Enterociccus (VRE)
56
Q

What causes Gram positive organisms to retain the crystal violet dye?

A

thick peptidoglycan cell walls with numerous teichoic acid cross-linkages

low permeability of decolorizer

low lipid content

57
Q

Define Light microscopy

A

also called brightfield microscopy, uses light passing through a specimen and a series of lenses to magnify the specimen visually

58
Q

What is this and what does it do?

A

Objective lense- the lens closest to the specimen

usually 4X, 10X, 40X, and 100X (oil immersion)

59
Q

What is the formula for total magnification?

A

magnification of objective x magnification of ocular

  • the ocular usually is 10X
60
Q

Define ocular lens

A

The lens closet to the eye which usually has a magnification of 10X

61
Q

Define resolution

A

the extent to which detail in the magnified object is maintained (sharpness, focus)

62
Q

Define contrast

A

the ability of the specimen to stand out from the background, staining improves and so does reducing the diameter of the aperture diaphram (but this will reduce resolution)

63
Q

Label the diagram

A
64
Q

What are the key diffrences between Prokaryotic and Eukaryotic cells?

A

Prokaryotes

  • no nucleus or membrane bound organells
  • always unicellular
  • DNA is circular
  • 70s ribosomes
  • no cytoskeleton
  • motility by flagellum
  • cell division by binary fission
  • always asexual reproduction

Eukaryotes

  • often multicellular
  • true nucleus and membrane bound organelles
  • linear DNA
  • 80s ribosomes
  • always has cytoskeleton
  • cell division by mitosis/meiosis
  • reproduce sexually or aesexually
65
Q

How are the quantities of bacteria expressed in the lab report?

A

rare, few, moderate, many

1+, 2+, ect

66
Q

What is it important to give the quantity on a report?

A

It helps to correlate smear results with the amount of growth observed in the culture.

67
Q

What color should phagocytes or white blood cells appear?

A

Pink or gram negative

68
Q

Name 2 causes for an organism to appear gram variable.

A

antibiotic treatment

old age

autolytic enzymes

69
Q

Gram stain morphology of Staphylococcus aureus.

A

Gram positive cocci in clusters

70
Q

Gram stain morphology of Klebsiella pneumoniae

A

gram negative rods

71
Q

Gram stain morphology of Salmonella

A

gram negative rods

72
Q

Gram stain morphology of Streptococcus agalactiae

A

gram positive cocci in chains

73
Q

Gram stain morphology of Neisseria meningitis

A

gram negative cocci/ diplococci

74
Q

Gram stain morphology of Haemophilus influenza

A

gram negative rods or coccobacilli

75
Q

What temperature is appropriate for the incubation of most bacteria?

A

35-37 degrees C

76
Q

What is the most common biosafety level?

A

2

77
Q
A

Microbiology (11 decks)

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