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micro > Week 1 > Flashcards

Week 1 Flashcards

Fundamentals

1
Q

What creatures does the study of microbiology include?

A

Bacteria, viruses, fungi, parasites

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2
Q

How much biomass does bacteria make up? (of the world’s total)

A

50%

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3
Q

How many more bacterial cells are there than human cells within the body?

A

10x

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4
Q

How much of the world’s O2 does bacteria produce?

A

50%

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5
Q

What three things do bacteria do that are super important for the environment?

A

1)Decomposition. 2)Nitrogen fixation 3) Oxygen production 4*)bioremediation

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6
Q

What percent of microbes cause disease?

A

1% Most bacteria assist in digestion or protect us from other bacteria

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7
Q

What are the four major microb classifications

A

Viruses, fungi, protozoa, bacteria/prokaryotes

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8
Q

What are the six general virus characteristics

A

1) Obligate intracellular parasites. 2) No cytopasmic membrane, cytosol, organelles* 3)Causes infections in animals, plants, fungi, and bacteria 4)Causes ‘plauges’ 5)not alive (no metabolic pathaways, no growth or response, no independent reproduction). 6)infect cells metabolic pathways

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9
Q

what are the four general characteristics of fungi

A

1) (chemo)heterotrophic - dont fix carbon (photosynthesis), but use them for growth. 2)chitinous cell walls. 3) uni or multicellular. 4) closely related to animals

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10
Q

What six things do fungi do that are significant to the environment

A

1) Decompose dead organisms (saprophytes). 2)Helps plants absorb water and minerals (Symbionts/commensals). 3)Used for food/bev manufacturing 4)Used for antibiotics. 5) used for research 6)Can cause infection (30% of cause)

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11
Q

What are the four characteristics of protozoa?

A

Eukaryotic, unicellular, lack of a cell wall, motile (bacteria are motile as well, but only flagella)

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12
Q

What does medical microbio focus on?

A

Pathogens that cause (human) disease

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13
Q

what family is TB from

A

Mycobacterium tuberculosis

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14
Q

What three ways can Protozoa be motile?

A

Cilia, flagella, or pseudopodia (exceptions are apicomplexans subgroup)

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15
Q

Where do protozoa live?

A

Moist environments. Critical members of planktons

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16
Q

Are protozoa pathogenic?

A

Yes, but very few

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17
Q

What genetics do prokayotes (not viruses) have?

A

DNA: single, circular chromosome in the nucleoid area (no cell wall). (plasmids encode specialized genetic info, EG pathogenicity or drug resistant genes)

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18
Q

Eurkaryotic cell characteristics (5)

A

Nucleus (membrane bound genetic), Internal membrane-bound organelles, larger 10-100x bigger than prokaryote, complex, includes: algae, protozoa, fungi, animals, plants

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19
Q

prokaryotic cell characterics (5)

A

Lack nucleus (nucleoid instead), lack mitotic apparatus, Lacks various interial membrane-bound structures, small (less than 1um in diameter), simple structure, include bacteria and archaea

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20
Q

What is the nucleoid

A

An area where a single, cilular chromosome is, without a nuclear membrane

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21
Q

What else is in the cytosol of a protkaryote?

A

Plasmids, Ribosomes, nucleoid

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22
Q

What is the cell envelope? what does it do?

A

Protects the cell from osmolarity, chemicals, antibiotics. Made out of the plasma membrane and the cell wall

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23
Q

What is the cell wall mostly composed of for a prokaryote?

A

Peptidoglycan

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24
Q

What does the cell wall do? what does the plasma membrane do? what is the cell envelope?

A

Cell envelope= Cell membrane + Cell wall
-Cell wall: Protects the cell from environment, helps with cell attachment
-Cell membrane: Selective permeability, concentration/electrical gradient maintenance, photosynthesis

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25
Q

What are the two types of bacterial cell envelope structures look like? Outside to inside

A

Gram-positive: Thicc peptidoglycan layer, plasma membrane. Held together with teichoic acid.
Gram-negative: Outer membrane with lipopolysaccarides as well as other PM stuff.

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26
Q

What are lipopolysaccharides? What do they do? where are they located?

A

They are located on the outside of a gram negative outer membrane. They are used in cell structure, protection, and signaling

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27
Q

What causes the stiff thick structure of a gram postiive peptidoglycan cell wall

A

Pentaglycine bridges

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28
Q

What causes serotypes in gram-pos bacteria

A

Teichoic and lipoteichoic acid

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29
Q

What is the cell wall component that determines serotype in gram-negative organisms

A

lipopolysaccharides (LPS)

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30
Q

What is an acid-fast organism?

A

Has a waxy cell wall due to mycolic acid, and so cannot be stained with water-based stains. Must use a Ziehl-Neelson stain, which uses acid to penetrate the cell wall

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31
Q

Other external bacterial structures

A

Glycocalyx: a gelatinous, sticky stubstance that surrounds the outside of the cell.
Flagella: long stucture that helps with cell movement
Fimbriae/pili: small hair like structures that promote adhesion of cell
Bacterial spore/ endospore: unique structure produced by bacterium in unfavorable conditions

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32
Q

What is an endospore?

A

Unique structures (only some bacteria) to protect them against unfavorable condintions

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33
Q

Gram positive or negative? Lipoteichoic acid, teichoic acid, and lipopolysaccharides (LPS)

A

lipoteichoic acid and teichoic acid : positive
LPS: negative

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34
Q

What is a glycocalyx? What are the two types

A

Gelatinous polysaccharide and protein complex that surrounds the bacterium. Used for anchorage, strength and desiccation resistance.
-Capsule: repeating layers of organic chemicals firmly attached to bacterium. Prevents cell recognition
- slime layer: loosely attached, water soluble layer. Helps with adhesion to surfaces.

35
Q

What are the four ways/methods to classfiy bacteria?

A

-Media growth
-Microscopy
-biochem
-immunolocial

36
Q

What is complex media? What is simple media?

A

Simple: just agar
Complex: additives that allows us to grow bacteria on solid-agar. Cannot grow viruses or paraistes because they need a host cell (obligate intracellular parasites).

37
Q

What are the three categories of complex agar media? Give an example of each.

A

non-Selective: No antibiotics or anything to stop organisms from growing. Trying to get everything to grow (BAP, choco BAP)
Selective: elimates or reduces large numbers of irrelevant bacteria. (MAC for enterobacteriaceae, CNA agar for STS and streph)
Differential: Makes use of bacteria’s biochemical properities (EG pigment, enzyme secretion). (MAC with its lac + and lac - stuff) (Chrom agar shows pathogenic versus non pathogenic Ecoli)

38
Q

What color does Salmonella/Shigella produce on MAC? how about Ecoli

A

Salmonella/Shigella: White
Ecoli: red

39
Q

What is microscopy?

A

Using a microscope and a stain to see a bacteria. Includes light (type dependent on organism of interest), electron , confocal scanning laser, and scanning probe microscopy

40
Q

What is Bright-feild microscopy

A

The normal one. Uses an objective and an ocular lens. Uses contrast differences with surrounding media to cause visability. Dead cell only

41
Q

phase contrast light microscopy

A

use light that passes thru cells in different phases depending on material properties. A special condenser then is used to make a 2D image with greater contrast than bright-field. Used to see living cells

42
Q

Differential interference contrast microscopy (DIC)

A

Uses polarized light in two beams that then converge to give the image inference –> more contrast. Good for living cells with fine detail with no staining. 3D image

43
Q

What is Darkfield microscopy

A

uses a transmitter to prevent light from directly illuminating the specimen, causing a dark background. Allows to see different bacterial components or specimens that are difficult to see with direct lighting

44
Q

What is flurorescence microscopy?

A

Organism is stained with a fluorescent dye, or immunofluorescence. Allows for greater contract and brighter illumination

45
Q

electron microscopy

A

Best contrast and visulaization. Uses magnetic coils and electron beams to ‘see’ the bacteria

46
Q

What are the two types of electron microscopy?

A

SEM: surface scan
TEM: Electrons move thru sample to see interior

47
Q

What is a direct examination of bacteria?

A

Samples are suspended in solution, but not stained. Includes: water, KOH 10% for protein dissolve, india ink or lugol iodine (contrast, not staining)

48
Q

What are some differential stains

A

Gram stain, acid-fast stain, iron hematoxylin stain, trichrome stain, ect … NOT Fluorscent stains

49
Q

What is the oxidase test?

A

Does the organism has cytochrome-C oxidase?

50
Q

What is the catalase test?

A

Does the organism have catalase to take care of toxic oxygen (OH)

51
Q

What do antibodies read as the epitope on microorganisms?

A

LPS, flagella, or capsular antigens

52
Q

What is an agglutination assay? What type of test is it?

A

An antibody is made to a specific microorganism or one of its compoents. The bacterial sample and the antibodies are put together. If positive, clumping will happen (at macroscopic level). This is a serological test

53
Q

What are the four bacteria shapes?

A

Bacillus (rods), coccus, spirllum (spiral), Spirochete (corkscrew), vibria (comma)

54
Q

How is subtyping determined (4)

A

Serologically. Biotyping (biochem tests). Antimicrobial susceptibiltiy testing. molecular methods (PCR)(using proteins, DNA, or RNA. Cannot recover organism, but doesn’t need isolation)

55
Q

Why don’t you run pulsed-feild gel electrophoresis electrial feild linearly?

A

DNA is too big. It would litterially get stuck. It needs to be giggled along. was like pre-PCR

56
Q

What are the four stages of binary fission?

A

1) cell elongation + DNA replication
2) Cell division starts: cross wall starts to form and DNA copies are pushed to opposite ends of the cell
3) Cross wall completely forms
4) cells separate

57
Q

What are the four types of culutre media?

A

Enriched non-selective, selective/differential media,

58
Q

What are some examples of enriched non-selective media?

A

Growths most organisms. EG: blood agar, buffered peptone water, Bolton’s broth (anaerobic bacteria)

59
Q

What are biocides?

A

Anything that can inactivate (not necessarily kill) a microorganism) (EG hydrogen peroxide, alcohol, bleach, heat, radiation, phenols)

60
Q

WHat is a bacteriostatic biocide?

A

A biocide that inhibits bacterial growth

61
Q

What is a bactericidial biocide?

A

A biocide that kills bacteria

62
Q

What does sterilization mean?

A

When a product or surface is rendered free of viable organisms (EG autoclaves)

63
Q

What does septic, anticeptic or aseptic mean?

A

Septic: pathogenic microbes in living tissues or associated fluid (typically in the blood)
Antiseptic: a biocide used on living tissue (EG detergent)
Aseptic: microogranism free

64
Q

MOA to stop microbe growth

A

Damage DNA, protein denaturation (heat or chemical), membrane disruption, cell wall disruption (EG penicillin)

65
Q

How to damage microbe DNA?

A

Ionizing radiation, UV light, DNA reactive chemicals

66
Q

What are three ways bacteria resist antibacterial agents

A

Physical barriers (EG Vancomycin), Genetically encoding (beta-lactamase), mutations in binding-sites

67
Q

What are some physical sterilizating agents?

A

Heat, radiation

67
Q

What are the MOAs of chemical agents (5)? Give examples.

A

1) Damage to DNA: UV, ionizing radiation, DNA-reactive chem
2) protein denaturation: heat or chemical agents
3) cell membrane/wall disruption: active transport or diffusion disruptions, enzyme disruption
4) Free sulfhydryl group (Cys) disruption: penicillin, oxidizing agents can form links, Mercuric ions
5) Chemical antagonism (enzyme interference): carbon monoxide, cyanide (binds to cytochrome C oxidase)

68
Q

what are the four microscopic examination methods

A
  • Direct examination
  • Differential stains
  • Acid-fast stains
  • Fluorescent stain
69
Q

What genus is the one with acid-fast bacteria

A

mycobacteria. Has leperesy and TB. *novocardia has some.

70
Q

What are two acid-fast stains? what are two fluorescent stains.

A

-acid fast: Ziehl-Neelsen, Kinyoun stain
-fluorescent: Auramin-rhodamine, acridine orange stain

71
Q

What are some classic ways to subtype bacteria via biotyping

A

biotyping = biochem
-sugar fermentation
-amino acid decarboxylation/deamination
-hemolysis

72
Q

What is the difference between Eubacteria and archaebacteria

A

Eubacteria = classic bacteria. Possess peptidoglycan layer, membranes, proteins, and DNA+machery
archaebactera = NO classic peptidoglycan cell wall. *
Cell wall lacking eubacteria mycoplasmas exsist

73
Q

What are three methods used during epidemics to id/subtype a microorganism

A

-biotyping
-serotyping
-antimicrobial susceptibility testing

74
Q

what do you call an Eubacteria that lacks a cell-wall ?

A

mycoplasmas

75
Q

What are some enriched non-selective media examples?

A

Blood agar (Nutrient media + blood), buffered peptone water (for bacteria only), Bolton’s broth (anaerobic bacteria)

76
Q

Whats a selective/differential media? give examples

A

Selective: only lets some organisms grow
differential : allows to differentiate between two bacteria
-MAC
-Xylose-lysin deoxycholate (XLD)
- Chromagar

77
Q

What elements are needed for bacteria to grow?

A

C, O, H, N, S, P, K, Na
-O2 is not required by all bacteria. toxic oxygen can be very rxtive.

78
Q

What are some toxic oxygen species?

A

peroxide anion, singlet oxygen, superoxide radicals, hydroxyl radicals

79
Q

What four things influence enzymatic rxn rate?

A

temp, pH, concentration, inhibitors if present

79
Q

What does catalase do?

A

It deals with toxic oxygen. Means it must be O tolerant

79
Q

What is the difference between obligate anaerobes and facultative anaerobes? what is the aerobic version of facultative anaerobes

A

-facultative anaerobes: okay either way. Equivalent is aerotolerant anaerobes
-obligate : need it

80
Q

Whats an inorganic enzyme?

A

a catalyst

81
Q
A

micro (7 decks)

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