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Principles of Disease > Primerano Exam 1 > Flashcards

Primerano Exam 1 Flashcards

1
Q

Zoonotic Infection

A

Exogenous microbes transmitted from animals to human

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2
Q

fomites:

A

inanimate objects which harbor the microorganisms, e.g. infants toys, shared toothbrushes.

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3
Q

Nosocomial infections.

A

Crowded conditions, poor sanitary practices, and impaired defense systems in hospitalized patients

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4
Q

Sterile tissues.

A

blood, deep tissue, and alveoli in lung.

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5
Q

bacteriocins

A

toxic bacterial proteins that kill other bacteria

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6
Q

Koch’s Postulates

A

1) The bacterium should be found in all people who have the disease. Also, the bacterium or its products should be found in parts of the body affected by the disease.
2) Bacterium should be isolated from the lesions of an affected person and able to be maintained in pure culture.
3) The pure culture, inoculated into a susceptible human volunteer or experimental animal, should reproduce the disease symptoms.
4) Same bacterium should be reisolated in pure culture from the infected animal or human.

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7
Q

Problems with Koch’s Postulates

A

1) Ignores the role of the host. Susceptibility and resistance can have a genetic basis and reduces the extent of correlation expected in postulate #1.
2) Fastidious organisms are harder to culture. Many organisms can’t be cultured at all.
3) Variability (in virulence) of a single bacterial species. Organisms can acquire new virulence traits by genetic exchange (e.g. lysogenic conversion).
4) We can’t ethically inoculate humans with dangerous/lethal for experimentation.
5) Polymicrobial infections.

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8
Q

Prokaryotes:

A

cells lack a membrane bound nucleus

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9
Q

Eukaryotes:

A

cells which have a defined nucleus

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10
Q

Bacteria are

A

unicellular prokaryotic organisms and as such lack a nuclear envelope as well as membrane-bound organelles.
cell wall

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11
Q

Fungi are

A

eukaryotic organisms which have a well-defined nucleus, membrane-bound cytoplasmic organelles and a cell wall

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12
Q

Fungi include

A

yeasts (unicellular), molds (multicellular and filamentous), and dimorphic fungi which can switch from yeast to mold.

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13
Q

Parasites (broad definition)

A

prokaryotic, eukaryotic or viral organisms that require a living host for at least part of their life cycle and cause disease to the host.

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14
Q

Parasites (narrow definition)

A

unicellular or multicellular eukaryotic organisms that require a living host for at least part of their life cycle and cause disease in the host.

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15
Q

Viruses are

A

intracellular parasites that lack cell structure; generally consist of nucleic acid genome surrounded by a protein coat; require a cellular host for replication.

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16
Q

Prokaryote Ribosome structure

A

70S Ribosomes (30S + 50S)

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17
Q

Prokaryote translation begins with

A

Translation begins with N-formylmethionine

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18
Q

Prokaryote respiration occurs where

A

Respiration occurs in plasma membrane

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19
Q

Viroid vs. prion

A

Viroids consist of RNA genome without any protein components

Prions are infectious agents consisting only of protein.

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20
Q

Flagella are required for what process?

A

movement of cell, toward a nutrient or away from a toxic substance, a process called chemotaxis

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21
Q

Flagella are composed of what protein?

A

flagellin

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22
Q

Pili (fimbriae) do what

A

thin, rigid appendages allow cells to adhere to host cell or other bacterial cell surfaces.

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23
Q

Pili (fimbriae) are composed of what protein?

A

composed of proteins called pilins;

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24
Q

Bacterial Capsule is made up of what?

A

Glycocalyx

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25
Q

Glycocalyx made up of what?

A 
usually polysaccharide (but occasionally protein) confers resistance to phagocytosis
gives colony a smooth or shiny appearance
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26
Q

Nucleoid:

A

discrete area containing the bacterial chromosome and plasmid DNA; bacterial DNA is
organized by histone-like proteins. No membrane is present

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27
Q

Cytoplasmic inclusion bodies:

A

sites where nutrient macromolecules (usually polysaccharides like glycogen) are stored as large microscopically visible complexes

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28
Q

Endospores:

A

heat-resistant, dehydrated multi-layered cells that are rich in calcium dipicolinate; formed within the cell by a process called sporulation; endospores germinate into growing cells when adverse conditions wane

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29
Q

Bacterial Cell Envelope =

A

Plasma membrane + cell wall + intervening material

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30
Q

Function of Plasma (Cytoplasmic or Inner) Membrane

A

(1) site of active transport
(2) respiratory chain components
(3) site of synthesis for phospholipids, peptidoglycan, LPS and capsular polysaccharides

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31
Q

Peptidoglycan structure of backbone

A

Glycan backbones consist of alternating N-acetylmuramic acid (M) and N-acetylglucosamine

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32
Q

What type of linkages are on peptidoglycan?

A

B-1,4 linkage

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33
Q

What enzyme cleaves B-1,4 linkage of peptidoglycan?

A

lysozyme

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34
Q

What allows peptidoglycan to form a ‘sacculus’ in G+ bacteria?

A

terminal D-alanine of tetrapeptides is covalently linked by a glycine pentapeptide

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35
Q

Muranyl Dipeptide

A

fragment of peptidoglycan: adjuvant, pyrogen (fever-causing), and somnagen

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36
Q

permeases

A

are required for active transport of nutrients (against a concentration gradient)

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37
Q

sites for the synthesis for the biosynthesis of peptidoglycan and outer membrane components (like LPS in g- organisms)

A

Plasma or Inner Membrane

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38
Q

Where is LPS located?

A

G- bacteria on outer most leaflet

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39
Q

Lipid A portion

A

is responsible for endotoxic activity; anchors LPS molecule in the outer leaflet

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40
Q

Core Polysaccharide contains

A

unusual eight carbon sugar 2-keto-3-deoxyoctulosonic acid (KDO); core is essential for LPS structure and bacterial viability

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41
Q

The O antigen forms basis for

A

serotypes of bacterial strains

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42
Q

LPS and LTA are both what?

A

amphipathic

43
Q

LTA can induce coagulation reactions but cannot do what/

A

cause fever (is not pyrogenic)

44
Q

Porins are

A

protein complexes that form channels that allow passive diffusion of small charged molecules.
Found only in outer membrane of g- bacteria

45
Q

Braun lipoprotein

A

covalently anchors the outer membrane to peptidoglycan. Inner leaflet of outer membrane.

46
Q

Omp proteins

A

stabilize the outer membrane and act as specific receptors

47
Q

What part of bacteria has been sequenced for identification?

A

16S ribosome

48
Q

Adhesins

A

(Afimbrial adhesins). Bacterial surface proteins which mediate intimate contact with the host cell
Gram + and gram- bacteria

49
Q

Biofilms.

A

The formation of dense, multiorganism layers on a surface. Especially significant in implants, etc

50
Q

Invasions:

A

causes the formation of pseudopod-like structures, which mediates bacterial engulfment.

51
Q

How do bacteria survive phagocytosis?

A

Some bacteria are able to produce catalase + SOD and have lysozyme resistant cell wall

52
Q

Siderophores/enterobactins

A

chelate iron effectively and bring inside cell.

53
Q

Diphteria Toxin is what kind of toxin?

A

AB Toxin

54
Q

Pore former (hemolysin)

A

acts to lyse the cell by permitting rapid H2O entry in response to the osmotic gradient. Cholesterol is often the target allowing entry/insertion into the host cell membrane.

55
Q

Phospholipase.

A

Enzymatically removes the charged head of phospholipids. This acts to destabilize the cell membrane, also resulting in cell lysis.

56
Q

Septic shock

A

Bacterial products hyperactivate the complement cascade leading to hypotension, DIC and organ failure.

57
Q

superantigens

A

antigen which binds to the MHC class II on phagocytes. This protein also binds to receptors on many T cells, with the release IL-2 and other interleukins. Septic Shock

58
Q

Sepsis is a problem caused by

A

bacteremia of both gram negative and gram positive origin

59
Q

LPS (endotoxin) results in what systemic effects?

A

DIC Thrombosis
Hypotension -> shock
Fever
Hypoglycemia

60
Q

Fermentation Defined

A

Glycolytic pathway followed by NAD+ regeneration

61
Q

Glycolysis Net equation

A

Glucose + 2 NAD + 2ADP + 2Pi —-> 2 pyruvate + 2 NADH + 2H + 2ATP

62
Q

What generates much of the total ATP under aerobic conditions

A

Oxidative phosphorylation

63
Q

Central metabolism provides intermediates for

A

nucleotide, amino acid and vitamin biosynthesis

64
Q

Nitrogen Fixation

A

N2 —-> NH3

65
Q

Ammonia assimilation

A

Many bacteria are able to assimilate NH3 into amino acids by various reactions.

66
Q

Organisms that require these molecules added to the growth medium are called

A

auxotrophs

67
Q

Those that have no requirements beyond simple C, N and S sources are called

A

prototrophs.

68
Q

Strict Aerobes require

A

oxygen for growth since little or no ATPgenerated via fermentation.

69
Q

Strict Anaerobes

A

little or no ATP via electron transport; lack superoxide dismutase, catalase and peroxidase, hence, oxygen is toxic.

70
Q

Aerotolerant anaerobes

A

aerobic and anaerobic
possesses Catalase and SOD - - or Mn++
Ferments in presence or Absence of O2

71
Q

Facultative anaerobes

A

aerobic and anaerobic
catalase and SOD
Respires with O2 and ferments in absence of O2

72
Q

Microaerophilic organisms

A

require or prefer low [O2]
no anaerobic
no catalase
only does oxidative phosphorylation

73
Q

General Secretory System

A

transports proteins to the gram-positive extracellular space or to the periplasm of gram-negative organisms.
located in cytoplasmic membrane and recognizes precursor proteins with hydrophobic N terminus (signal peptide)

74
Q

What passes through bacterial membrane by passive diffusion?

A

Very small molecules, water and gases.

75
Q

Energy independent channels (porins) transport what?

A

small hydrophilic solutes to pass through the outer membrane

76
Q

Glycerol transport is mediated by what found in the cytoplasmic membrane of gram-negatives

A

glycerol facilitator protein (facilitated diffusion)

77
Q

mechanism of the transport of glucose and other sugars go through bacterial membranes how?

A

Group translocation via PTS system

78
Q

Siderophores are

A

macromolecules that bind iron in the medium and transport it inside the cell

79
Q

Pathogenicity Islands:

A

cluster of genes encoding proteins involved in pathogenesis

GC content of island is often different than the host genomes

80
Q

Semi‑conservative replication

A

each daughter duplex DNA molecule is composed of one parental strand and one newly‑synthesized strand

81
Q

oriC

A

single site on chromosome where all DNA replication is initiated.

82
Q

Bidirectional replication

A

Two replication forks begin at oriC and travel in opposite directions around the circular chromosome

83
Q

DNA Polymerases

A

All bacterial polymerases share 5’ to 3’ polymerase activity and 3’ to 5’ exonuclease (proofreading) activity which is necessary for maintaining a lower error rate.

84
Q

Supercoiling:

A

Bacterial chromosome has negative superhelicity which means that it can readily convert to a molecule with unwound helical regions. Negative superhelicity is absolutely required for DNA replication.

85
Q

RNAP does what?

A

single enzyme transcribes all four types of RNA (not true in eukaryotes)

86
Q

sigma factor

A

initiation site specificity to holoenzyme, so that holoenzyme recognizes -10 and -35 positions of the promoter.

87
Q

Rho factor

A

assists in termination in some genes

88
Q

consensus sequence is

A

the sequence found most frequently in a survey of a large number of sequences

89
Q

the more similar a sequence is to the consensus, the stronger the

A

promoter.

90
Q

PolyA tails in prokaryotes. true or false?

A

false

91
Q

Two subunits of bacterial ribosome

A

30S + 50S (70S)

92
Q

30S plays a role in

A

translation initiation and has

site for tRNA binding.

93
Q

50S primary function

A

Primary function = peptide bond formation (transpeptidase)

94
Q

tRNA synthetases catalyze

A

addition of amino acid to tRNA

95
Q

degenerate

A

that is more than one codon can code for a given amino acid

96
Q

The rate of translation initiation is controlled by a sequence present in the 5’ non translated region of all prokaryotic mRNAs

A

ribosome binding site or Shine-Dalgarno (S‑D) sequence.

97
Q

the A site

A

Accepts incoming charged tRNA.

98
Q

P site

A

is the site where peptidyl tRNA sits.

99
Q

transpeptidation step

A

Transfer of peptidyl residue to free amino group of charged tRNA molecule in the A site.

100
Q

Peptidyl transferase activity is located

A

in the 50S subunit

101
Q

Coupling

A

can only occur in prokaryotes. Nucleus physically separates the processes of transcription and translation

102
Q

What reactions require energy consumption in transcription/translation

A
  • Active transport
  • DNA AND RNA SYNTHESIS
  • tRNA CHARGING
  • PEPTIDE SYNTHESIS (INITIATION AND ELONGATION)
103
Q

sequential use of carbon sources is called

A

diauxic growth.

Principles of Disease (8 decks)

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