The Final Countdown Flashcards Preview

Microbiology > The Final Countdown > Flashcards

Flashcards in The Final Countdown Deck (114):
1

Robert Hooke

Built first compound microscope, looked at cork, coined term cell

2

Antonie van Leeuwenhoek

observed single-celled microbes and called them "small animals", built single-lens magnifiers

3

Francesco Redi

Disproved spontaneous generation through the cover over meat experiment

4

Lazzaro Spallanzai

Disproved spontaneous generation by boiling broth covered and uncovered

5

Louis Pasteur

Disproved spontaneous generation by heating broth in swan neck bottles, one broken and one normal

6

Robert Koch

Established postulates which established a link between a specific microbe and disease

7

Koch's Postulates

1) microorganism is present in every case of disease and not in healthy people
2) Microorganism must be grown in pure culture
3) Same disease must result when a healthy host is infected with disease
4) the same strain of microbe must be obtained from the new diseased host.

8

Berry Marshall

Swallowed bacterium to give himself stomach ulcers to prove his theory right

9

Florence Nightingale

Used medical statistics to demonstrate the significance of mortality due to disease

10

Alexander Fleming

Discovered penicillium mold generated a substance that kills bacteria

11

Howard Florey and Ernst Chain

Purified penicillin to make first commercial antibiotic

12

Sergei Winogradsky

Studied microbes in natural habitats, discovered lithotrophs, developed enrichment cultures, built Winogradsky column

13

Bright Field Microscope

light source on specimen to produce a virtual image that shows something is there but can't see specifics or viruses

14

Dark field Microscope

shows microbes as halos of bright light against darkness, useful for narrow cells

15

Phase contrast

Shows refractive difference in cell components (shows internal components)

16

Fluorescence microscopy

adds dye or protein (fluorophores) to specimens to show fluorescent image of object, protein, structure

17

Basic Dyes

Methylene blue/ crystal violet/ safranin, bind to negatively charged molecules

18

Acidic Dyes

Eosin/ Rose bengal, bind to positively charged molecules

19

Gram stain procedure

Add crystal violet->both are purple
Then add Iodine as a mordant to trap the dye in the cell wall-> both still purple
Add alcohol (decolorizing step)-> now only gram positive is purple, gram negitive is clear
Clear cells are low contrast so a counter stain is added (safrin) to see gram negative cells as pinkish/red
Safrin does stain gram positive but the violet is too dark to see it

20

Electron Microscope

Electrons used instead of light, used for viruses and small cell structures

21

Scanning electron microscope

Shows surface details and color

22

Transmission Electron Microscope

Shows interior details and components (color can be computer generated)

23

Bacteria Characteristics

Single celled, Peptidoglycan cell wall, Lack membrane bound nucleus, Found in soil/water/air, Some species may survive extreme temp/pH/salt

24

Archaea Characteristics

RNA sequences, Unusual metabolic characteristics, Usually found in extreme temp/pH/salt, associated with extreme enviornments, Don’t have peptidoglycan in their cell walls but can have pseudopeptidoglycan:
N-Acetyltalosaminuronic,
use L-glycerol and have ether links

25

Chemotaxis

the movement of a bacterium in response to chemical gradients.
Attractant=CCW rotation
Repellent=CW rotation

26

Biofilm

Attached bacteria form complex, slime enclosed communities containing Exopolysaccharide that makes it sticky, form when nutrients are plentiful

27

Quorum sensing

communication of microcolonies to form biofilms

28

Peptidoglycan (Murein) Structure

Meshlike polymer of identical subunits forming long strands containing 2 sugars and amino acids.
Two alternating sugars:
N-acetylglucosamine (NAG)
N- acetylmuramic acid (NAM)

29

Bacterial resistance

bacteria produce beta-lactamases to keep penicillin from binding to the cell wall, or they have efflux pumps that pump penicillin out of the cells

30

why are gram positive bacteria purple?

The teichoic acid threads retain the stain

31

Thermophiles or Hyperthermophiles adaptions

They have increased hydrogen bonds, less flexible polypeptides, and other DNA binding proteins to stabilize in extreme heat
ex. Taq DNA polymerase

32

How do cells survive in a hypotonic environment

They have pressure sensitive channels in the plasma membrane to allow solutes to leave the cell

33

How do cells survive in a hypertonic environment

The cells can increase cellular osmotic concentration by synthesizing or importing solutes

34

Adaptations of Halophiles

Have ion pumps to excrete sodium and replace it with other cations like potassium

35

Adaptations of Psychrophiles

Have unsaturated fatty acids to allow the membrane to remain semi-fluid in the cold

36

Organotrophy

involves organic electron donors and inorganic or organic terminal electron acceptors.

37

Lithotrophy

involves inorganic electron donors and inorganic or organic terminal acceptors.

38

Phototrophy

involves photo (light) excited electrons

39

Frederick Griffith

Studied Streptococcus pneumoniae in mice
Hypothesized that the bacteria could “transfer information” to each other, smooth strains caused cell death and even killed could pass the fatal gene to different cells of a different strain

40

Conjugation

Horizontal gene transfer requiring cell contact. Live cell to live cell

41

DNA supercoiling

condenses chromosome to keep it in one small area, done by topoisomerases

42

Positive DNA supercoiling

DNA is overwound, extreme archaea have it

43

Negative DNA supercoiling

DNA is underwound, not as tight, found in bacteria, eukaryotes, and some archaea

44

Initiation of replication of DNA

starts at single origin of replication, replication bubble forms and 2 replication forks move in separate directions, DnaA initiates replication (rise as cell grows and is activated by binding of DnaA-ATP complexes) and SeqA inhibits replication

45

Transformation

is the process of importing free DNA into bacterial cells.
Cells must be competent which is generated by quorum sensing and Competence factor will induce it (except in gram negative bacteria)

46

Methyl Mismatch repair

is based on recognition of the methylation pattern (parent strand) in DNA bases, hopefully parent strand has correct sequence so MutS can bind to mismatch and it can be looped, cleaved by MutH and repaired and replaced with the correct sequence

47

Nucleotide excision repair

An endonuclease removes a patch of single-stranded DNA containing damaged bases.
Does not distinguish between parental/daughter strands.

48

Jacques Monod and François Jacob

proposed idea that genes could be regulated by studying E.coli and inducible lactose enzymes, glucose is preferred carbon source

49

Lactose operon

Only turns on gene for lactose utilization if there is lactose in the media- induction because LacZYA operon makes glucose from lactose but you don't need it if glucose is already available

50

EMP pathway

most common form of glycolysis occurs in the cytoplasm of the cell, and functions in the presence or absence of O2, has 2 stages the glucose activation stage and Energy yielding stage, yields 2 pyruvate, 2 ATP, and 2 NADH

51

ED pathway

Studied mostly in prokaryotes, occurs in the cytoplasm, enables intestinal bacteria to feed on mucus, less efficient, most primitive, yields 1ATP, 1 NADH, and 1 NADPH

52

PPP Pathway

Occurs in the cytosol of the cell (aqueous component of cytoplasm), can operate independently or at the same time as other pathways, no oxygen requirement, yield 1 ATP and 2 NADPH

53

Antibiotic classification- Broad Spectrum

Effective against many species

54

Antibiotic classification-
Narrow Spectrum

Effective against few or a single species

55

Antibiotic classification- bactericidal

antibiotics kill target organisma

56

Antibiotic classification- bacteriostatic

antibiotics prevent growth of organisms so immune system can take care of it and create antibodies against it

57

Minimal Inhibitory Concentration

is the lowest concentration that prevents growth, tested by diluting antibiotic

58

Dimitri Ivanovsky

Studied Tobacco Mosaic Disease, observed agent was not removed by filters

59

Beijerinck

Studied Tobacco Mosaic Disease:
agent must be so small it passes through filters

60

Loeffler and Frosch

Studied foot and mouth disease

61

Petyon Rous

Studied sarcomas (tumors) in chickens, diseased chickens could transmit tumors to healthy chickens= cancer transmitted by a virus

62

Virus characteristics

molecule of DNA or RNA enclosed in coat of protein (nucleocapsid), cannot reproduce independent of living cells nor carry out cell division, helical or icosahedral or complex shape, variety of genome types

63

lytic cycle

Bacteriophage quickly replicates, killing host cell, causes cell burst by creating an enzyme that breaks down cell walls, can be triggered by stress

64

Lysogenic cycle

Bacteriophage is quiescent, integrates into cell chromosome, as a prophage, can reactivate to become lytic

65

Herpes Virus characteristics

-Icosahedral
-Enveloped
-Spiked
-Tegument (layer of proteins around it)
-dsDNA
-attach to host heparan sulfate and full atachment requires nectin
-enter via fusion or endocytosis
-release via exocytosis and by upregulating host heparanase

66

Mutualism

each partner species benefits from the other and may fail to grow independently ex. lichen

67

Synergism

optional cooperation where both species benefit, but can grow independently, ex. gut flora

68

Commensalism

One species benefits, while the partner species neither benefits nor is harmed, ex. Beggiatoa in wetlands, consume H2S and help out other organisms

69

Amensalism

One species benefits by harming the other.
Relationship is nonspecific, ex. strepomyces that secrete antibiotics into soil

70

Parasitism

One species benefits at the expense of the other, ex. legionella

71

Coral Bleaching

Under stress the Zooanthellae are expulsed from the coral, or can occur due to infectious disease from Vibrio shiloi bacteria that kill zooxanthellae

72

Milk --> Cheese

obtain milk and pasteurize it --> add starter cultures (bacteria ferment and pH declines, milk proteins unfold exposing hydrophobic residues)--> rennet added (sometimes) and caseins are cleaved into hydrophobic (curds) and hydrophilic (whey) components --> add salt to curds --> age with microbes

73

Innate immune system physical barrier-skin

Keratinized
Slightly acidic
Has SALT (the Langerhans cells that digest forgien debris and take to other immune cells for them to determine if an immune response is appropriate)

74

Innate immune system physical barrier-mucous membrane

Traps pathogens
Has products that can destroy pathogens
-Lysozyme- hydrolyzes sugar bonds in peptidoglycan
-Lactoferrin- keeps iron from plasma
-Lactoperoxidase- creates superoxide radicals

75

Innate immune system chemical barrier-bacteriocins

Peptides produced by normal flora.
-Lantibiotics: Many Gram (+)
Forms holes in target cell membrane.

-Colicins E. coli (Gram -)
Damage DNA, stop protein synthesis, & forms holes in inner membrane.

76

Innate immune system chemical barrier- complement

Host serum proteins that augment (or “complement”) the antibacterial activity of antibodies.
-Have signals that recruit phagocytes to their activation site.
- Can puncture cell membranes causing cell lysis.

77

Innate immune system chemical barrier- cytokines

Soluble proteins that act as signaling molecules.
-Proliferation
-Differentiation
-Apoptosis
-Cell movement (chemokines)

78

Innate immune system chemical barrier- Interferons

Type of cytokine
-Type I: Bind to receptors on uninfected host cell, and render them resistant to viral infection.
Cleave dsRNA and block viral RNA translation.
-Type II: Has immunomodulatory function

79

Innate immune system physical barrier- Inflamation (signs)

Nonspecific, can release kalikrein to increase capillary dilation and blood flow, fibrin clots, phagocytes accumulate in inflamed area
5 Cardinal signs:
-Redness
-Warmth
-Pain
-Swelling
-Altered function

80

Innate immune system- fever

Pyrogens are substances that raise the hypothalamus set-point: 98.6˚F
-Impairs microbial growth.
-Activates immune cells.

81

Innate immune system- phagocytes

“Eating Cells”
-Dendritic Cells
-Macrophages
-Neutrophils
host cells have CD47 to differentiate

82

Innate immune system- natural killer cells

Destroy infected and cancerous host cells
-healthy host cells make MHC class 1

83

Adaptive immunity- Humoral immunity

B cells produce antibodies (when differentiated into plasma cells)
that directly target antigens of invaders, recognize epitotes, presents helper T cells with a piece of antigen and it is activated by a peptide

84

Adaptive immunity- Cell-mediated immunity

Antigen presenting cells activate T helper cells which rapidly divide and activate cytotoxic T cells which can directly kill infected host cells, handles intracellular microbes

85

Superantigens

Stimulate stronger immune response than normal antigens by “tricking” T cells into activation, nonspecific and evoke global T cell response

86

Infectivity

measured by the number of microbes that will cause infection in half of test animals

87

Virulence

Measured via the number of microbes that kill half of test animals.

88

Easiest way to transmit disease

through a sneeze or cough

89

Active invasion

Utilizes lytic substances.
Lytic substances “attack” normal host tissue
ex. collagenase and streptokinase

90

Invasion Passive

Chance scenarios allow spread to deeper tissues.
Ex. Insect bites or wounds

91

Enriched media

blood (complex media with specific blood components)

92

Selective media

favor growth of one species over another ex. only gram negative grow on MacConkey

93

Differential media

exploit differences between 2 different species that grow equally well ex. only colonies that ferment will be pink

94

Hetero

Rely on other organisms for carbon source, release CO2

95

Auto

Reduce CO2 for carbon to make complex cell constituants

96

Chemo

Energy from oxidation-reduction reactions

97

Why are enzymes useful?

Bring substrates close together at specific sites (active sites) to react which can lower activation energy

98

Competitive inhibition

Competes at active site to fill it and keep the substrate from binding ex. penicillin

99

Noncompetitive inhibition

Competes at allosteric site to change enzyme conformation

100

Deep branching Thermophiles- Aquificae

“Water maker”-
Oxidizes hydrogen gas to form water.
-Found in thermal vents
-Ether linked membrane lipids.
- grows long rod shape in wild, and forms pink streamers

101

Deep branching Thermophiles- Thermotogae

“Toga”-Loosely bound sheath, absence of “classical” outer membrane- possible advantage in high heat
-Mosaic (shared) genomes (bacterial-archaeal)
-Gram negative (atypical)

102

Deep branching Thermophiles- Chlorofelxi

-photoheterotrophs
-have chlorosomes and are green
-sulfur is toxic
-filamentous shape
-form biofilms in hot springs

103

Cyanobacteria

-oxygenic
-gram negative, but with thick peptidoglycan
-appear green
-mutualistic associations in microbial mats
-no standard cell shape, can be multicellular
-have heterocysts for nitrogen fixation, thylakoids for photosynthesis, and carboxysomes to fix CO2

104

Gram positive firmicutes

-Low GC
-many form endospores
-many are pathogens ex. botulism

105

Gram positive Actinobacteria

-High GC
-form complex multicellular filaments
-some are acid-fast- technically stained gram positive but it is difficult to stain

106

Proteobacteria

-gram negative
-most likely arose from a single ancestor
-ex. E.coli

107

Phylogeny of eukaryotes

Algae and green plants, protists, Fungi and animals

108

Tamiflu

competitive inhibitor for neuraminidase so influenza can't release from host cell, must be taken early into infection

109

Acyclovir

Antiviral, acts as nucleotides, incorporated into viral DNA, stops polymerization of herpes virus

110

Docosanol

-Changes the host cell membrane which surrounds healthy cells so that virus can't enter cells
-not an antiviral, in order to be effective must be applied at earliest signs of outbreak

111

Bacitracin

Peptidoglycan (cell wall) synthesis is halted so precursors are never carried across the cell membrane

112

Vancomycin

inhibits cell wall synthesis of Gram + bacteria by inhibiting transpeptidase by binding to substrates

113

itraconazole

treats fungal infections ex. blastomycosis, weakens cell membranes

114

Penicillin

a competitive inhibitor that prevents transpeptidine substances (peptidoglycan precursors) from building the cell wall