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Pathogenic Microbiology > Exam 1 Study Deck > Flashcards

Exam 1 Study Deck Flashcards

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Biology 101 flashcards
1
Q

how does a light microscope work and what is it used for

A

uses light and a magnifying lens to view small objects

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2
Q

how does a digital microscope work

A

uses optics and a digital camera to output an image to a monitor

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3
Q

how does a fluorescence microscope work

A

uses fluorescence to generate an image
used in conjunction with a flourescently stained organism which will produce a color when exposed to a wavelength of light

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4
Q

how does a phase contrast microscope work

A

light is shone through a transparent specimen
phase shifts are converted to brightness changes in the image

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5
Q

how does a dark field microscope work

A

light it shone at a specimen and produces a dark area around the specimen
this darkness occurs because there is nothing in those areas to scatter the beam of light

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6
Q

how does an electron microscope work

A

uses a beam of accelerated electrons as a source of illumination

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7
Q

what are the some phenotypic ways to classify an organism

A

size
shape
hemolysis
texture
rate of growth
color
odor

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8
Q

what is the difference between genotype and phenotype

A

genotype: unique, genetic DNA
phenotype: observable expression (ex. size)

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9
Q

what are the two modes of transmission of diseases

A

direct and indirect

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10
Q

what are 5 examples of direct transmission of disease

A

1.) direct contact
2.) droplet infection
3.) contact with soil
4.) inoculation into skin or mucosa (vaccines)
5.) transplancental (vertical)

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11
Q

what are 5 examples of indirect transmission of disease

A

1.) vehicle (water, food, air, and medical devices)
2.) vector (animals, insects, and other humans)
3.) air
4.) fomite (objects likely to carry infection like furniture)
5.) unclean hands and fingers

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12
Q

what are the two intervening agents for modes of transmission

A

vectors and vehicles

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13
Q

what makes up the specific immune response

A

memory through previous exposures (vaccines)

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14
Q

how does the ingestion and removal process of invaders work

A

phagocytes ingest the bacteria by endocytosis
they engulf in phagosomes which then fuse with lysosomes
toxic chemicals in the lysosomes destroy the invaders

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15
Q

which antibody is the most abundant antibody produced

A

IgG

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16
Q

which antibody is the largest in size and is the initial antibody produced in reaction to an infection

A

IgM

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17
Q

which antibody is found in various body fluids

A

IgA

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18
Q

which antibody is secreted in parasitic infections and during allergies

A

IgE

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19
Q

which antibody is attached to the surface of specific immune system cells and is involved in the regulation of antibody production

A

IgG

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20
Q

generally, how does antibody-mediated immunity work

A

B-cells are stimulated by helper T-cells to become plasma cells and memory B-cells
plasma cells make antibodies

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21
Q

generally, how does cell-mediated immunity work

A

helper T-cells stimulate cytotoxic T cells
memory T-cells are created

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22
Q

what are virulence factors

A

characteristics of organisms allow them to cause disease in humans

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23
Q

what are the 5 main virulence factors

A

1.) ability to attach
2.) ability to invade
3.) ability to survive inflammation
4.) ability to survive against the immune system
5.) production of microbial toxins

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24
Q

what are the three methods of accomplishing diversity in bacteria

A

1.) mutation
2.) genetic recombination
3.) gene exchange

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25
Q

what is a mutation

A

a change in the original nucleotide sequence of a gene within an organism’s genome

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26
Q

what is genetic recombination

A

pieces of DNA that are homologous (similar) are exchanged

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27
Q

what are the three types of gene exchange

A

1.) transduction
2.) transformation
3.) conjugation

28
Q

what is transduction

A

DNA from a virus is packaged in a bacteriophage
bacteriophage then infects bacterial cell

29
Q

what is transformation

A

donor cell lyses to release DNA
DNA is then uptaken and exchanged with other pieces of DNA

30
Q

what is conjugation

A

chromosomal or plasmid transfer of DNA by an intracellular bridge

31
Q

what is differential media

A

media that allows you to differentiate between organisms based on what is added to the media

32
Q

what is selective media

A

media that is selective for only certain types of media (will kill all other types of organisms)

33
Q

what is MacConkey agar selective for

A

gram negative rods

34
Q

what is MacConkey agar differential for

A

lactose fermenters and bile positive organisms

35
Q

what is 5% Sheep Blood Agar differential for

A

hemolysis (beta, gamma, and alpha)

36
Q

what is CNA agar selective for

A

gram positive cocci and rods

37
Q

what is CNA agar differential for

A

hemolysis (beta, gamma, and alpha)

38
Q

what two things does CNA agar contain to suppress Gram negative organisms

A

colistin and nalidixic acid

39
Q

chocolate agar best grows what

A

fastidious bacteria like Hemophilus and Neisseria

40
Q

what is chromogenic media used for

A

used to select and differentiate bacteria by color

41
Q

what is the single most important phenotypic identifying characteristic used to identify organisms

A

the gram stain

42
Q

what is the main difference between gram positive and negative organisms

A

gram positive: thick peptidoglycan layer covering a cytoplasmic membrane - no outer later
gram negative: cytoplasmic membrane covered by a thin peptidoglycan layer covered with a thick lipopolysaccharide layer

43
Q

what are the 5 steps to a gram stain

A

fixation
crystal violet - purple dye
iodine treatment - forms a complex between the violet and iodine
decolorization - thins out the peptidoglycan layer, gram negative lose their color
counter stain (safranin) - stains red/pink

44
Q

what happens during the decolorization step of the gram stain

A

alcohol strips the gram negative bacteria of their outer wall and washes away the violet and iodine - leaving them colorless
gram positive bacteria are unaffected due to their thick peptidoglycan layer and lack of outer cell wall

45
Q

what happens during the counter stain step of the gram stain

A

colorless gram negative organisms now stain pink and gram positive organisms stay purple

46
Q

what does MALDI-TOF stand for

A

matrix-assisted laser desorption ionization time of flight mass spectrometry

47
Q

explain the steps of the MALDI-TOF

A

1.) colony is applied to a stainless steel plate and allowed to dry
2.) chemical matrix is added and allowed to dry
3.) plate is placed in the instrument and a laser is applied
4.) matrix absorbs the energy transferring heat to proteins in the sample
5.) soft ionization causes ions to float up a vacuum tube based on their size and charge
6.) a spectrophotometer measures the ions and protein charges to mass ratio and creates a graph unique to the organism

48
Q

what are some of the benefits of the MALDI-TOF method

A

-measures microbial proteins so it provides a more reliable means of discriminating one species from another
-good for differentiating organisms with complex nutritional requirements
-it’s very quick which allows patients to get treated more quickly
-expensive to purchase at first but saves money in the long run
-faster to get diagnosis of things like yeasts and anaerobes

49
Q

what are the three types of bacterial resistance

A

intrinsic (inherent)
aquisitional
mutational

50
Q

what is intrinsic resistance

A

organism is inherently not susceptible to the antibiotic

51
Q

what is aquisitional resistance

A

organism codes for certain proteins that make it resistant to an antibiotic

52
Q

what is mutational resistance

A

organisms can get resistant mutant genes through normal bacterial genetic exchange, thus making them resistant to an antibiotic

53
Q

what are the 5 general mechanisms of antibiotic resistance

A

1.) decreased cell permeability
2.) active efflux
3.) enzymatic inactivation of the antibiotic
4.) altered target (modification of drug receptor site)
5.) synthesis of a resistant metabolic category

54
Q

how do plasmids play a role in antibiotic resistance

A

the plasmid is a small, circular piece of DNA
these plasmids can contain antibiotic resistant genes these genes can be transferred through conjugation, transduction, or transformation
this allows bacterial to share antibiotic genes with their neighbors - thus making them harder to kill

55
Q

what are the three main key elements of host vs microbe interactions

A

relationship, physical encounter between the two, compromise

56
Q

what is the relationship like between a host and microbe

A

extremely complex
most situations are mutually beneficial but can vary

57
Q

what is the physical encounter like between host and microorganism

A

microorganisms colonize on the host’s surface where they can enter, invade, and spread

58
Q

what are the three types of compromises that can create favorable conditions for the development of disease between a microbe and its host

A

normal flora disruptions
reduced immunity
introduction into host via injury

59
Q

what is an opportunistic pathogen

A

one that does not normally cause harm unless something specific happens to the host (trauma)

60
Q

what is the definition of antibiotic

A

means “against life”
substance produced by a microorganism or by chemical synthesis which inhibits the growth of or kills microorganisms

61
Q

what are some desired characteristics in an antibiotic

A

toxic against pathogen but not host
high LD50
low MIC and MBC
bacterial
broad or narrow spectrum depending on infection
lack of side effects
ability to cross outer and cytoplasmic membranes
resistant to inactivation by microbial enzymes

62
Q

what is LD50

A

lethal dose 50% - dose of an antibiotic to kill 50% of the microorganisms

63
Q

what is minimal inhibitory concentration (MIC)

A

measure of the concentration of the minimum antibiotic necessary to inhibit growth of pathogen

64
Q

what is minimal bactericidal concentration (MBC)

A

measure of the concentration of the minimum antibiotic necessary to kill the target pathogen

65
Q

what are the two main types of presentations of infections

A

acute vs chronic

Pathogenic Microbiology (3 decks)

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