PID BLOCK3- bacteriology Flashcards

1
Q

Ribosomes

A
  • ribonucleoproteins w large 50s and small 30s subunit
  • protein synthesis + translation

-target for antibiotics

  • 16s rRNA gene encoding for 30s subunit used for reconstructing phylogenies
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2
Q

Plasma membrane

A

inner membrane next to cytoplasm
-PHOSPHOLIPID BILAYER + PROTEINS

-where energy is stored

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3
Q

Proteins in the plasma membrane

A
  1. Transport proteins
  2. Energy generation components
  3. Proteins that anchor or help assemble
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4
Q

Transport proteins

A
  • in the plasma membrane

-transport of specific molecules in and out of cell

  • mediates passage of hydrophilic substances
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5
Q

Energy generating components

A

synthesis of ATP in plasma membrane

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6
Q

Phospholipid bilayer

A

Part of plasma membrane

-hydrophobic/hydrophilic sides

-Hydrophobic/ lipid solube can pass with passive diffusion

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7
Q

Main functions of plasma membrane

A
  1. Selective permeability barrier
  2. Bacterial respiration and energy generation
  3. Anchor for external structures
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8
Q

Cell wall

A

PEPTIDOGLYCAN LAYER

-mesh like structure containing alternating subunits of NAG and NAM cross-linked w peptides by transpeptidase enzymes called Penicillin binding proteins (PBPs)

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9
Q

Peptidoglycan

A

Bacteria cell wall, good target for antibiotics

polymer unique to prokaryotic cells

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10
Q

Penicillin- binding proteins

A

PBPs

  • transpeptidase enzymes that connect with NAG and NAMs in cell wall
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11
Q

Function of cell wall

A
  1. Protection against mechanical damage and osmotic lysis
  2. Transport: non selective permeability
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12
Q

Outer membrane

A
  • Only in Gram neg bacteria

Protein containing asymmetrical lipid bilayer (LIPOPOLYSACCHARIDE or endotoxin)

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13
Q

Function of outer membrane

A

Only in gram neg

  1. Selective permeability
  2. Resistance to large or hydrophobic toxic compounds
  3. Tolerance to detergents + bile salts
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14
Q

Lipopolysaccharides

A
  • in the outer membrane of gram neg bacteria

-virulence factor

lipid A component = endotoxic activity

Mediator of septic shock

heat stable

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15
Q

Symptoms of LPS

A
  • Fever
  • Leukopenia
  • Anorexia
  • Diarrhea
  • Blood coag
  • Hemorrhagic shock
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16
Q

The exceptions to the 2 main structural classes of bacteria are?

A

Mycobacteria and Mollicutes (mycoplasma)

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17
Q

Mycobacteria

A

Bacterial envelope is gram + but contains MYCOLIC ACID

-Acid fast staining for identifying

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18
Q

Mollicutes (Mycoplasma)

A

Plasma membrane w sterols

NO CELL WALL- no peptidoglycan layer

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19
Q

Capsule

A

POLYSACCHARIDE LAYER

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20
Q

Function of the capsule

A
  1. Protection
  2. Virulence factors
  3. Nutrient reserve
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21
Q

Endospores

A
  • Cryptobiotic state of dormancy, most durable

-Produced by Bacillus and Clostridium

-keratin spore coat helps survival

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22
Q

Function of endospores

A
  1. Ensure survival during adverse enviro conditions
  2. Dormant, highly resistant bodies
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23
Q

Flagella

A

-on bacterial surface

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24
Q

Flagella function

A

locomotion or bacterial motility

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25
Q

Pili/Fimbriae

A
  • Fine, straight hair-like, attached to cell wall
  • Most common on Gram neg bacteria

for adhesion

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26
Q

Function of pili/Fimbriae

A
  1. Adhesion to host tissues
  2. Contribute to antigenicity
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27
Q

Bacterial colony

A

single bacterium multiplies on solid growth media.

Growth of bacteria produces a colony that is visible without microscope

28
Q

Different morphology depends on

A

Culture medium
Incubation time
Temp
Oxygen
Genetic differences

29
Q

Environmental factors of bacterial growth

A
  1. Nutrients
  2. pH (best growth @ 7.2-7.4)
  3. Ionic strength + osmotic pressure
  4. Light
  5. Temp (most are mesophilic w growth at 30-37 C)
  6. Gaseous requirement: O2 or CO2
30
Q

Classification of bacteria based on O2

A
  1. Obligate aerobes
  2. Obligate anaerobes
  3. Facultative anaerobes
  4. Aerotolent anaerobes
31
Q

Generation time

A

time required for a single bacterial cell to yield 2 daughter cells (30 min- 20 hrs)

32
Q

How do bacteria replicate?

A

Binary fission

33
Q

Bacterial growth curve

A
  1. Lag phase
  2. Exponential phase/ logarithmic phase
  3. Maximal stationary phase
  4. Decline phase/ death phase
34
Q

Lag phase

A

cell size increases

active metabolism but no division

35
Q

Exponential or Logarithmic phase

A

cells multiply at maximum rate

36
Q

Maximal stationary phase

A

Due to exhaustion of nutrients or toxic byproducts

Growth is ceased

37
Q

Fungal characteristics

A
  1. Eukaryotic
  2. Non-photosynthetic heterotrophs
  3. Aerobic growth

Cell membrane contains sterols (ergosterol) and chitin

38
Q

Mycelium

A

filamentous mass of hyphae

39
Q

Convalescent carrier

A

recovered but continues to shed pathogen

Ex: strangles in horses

40
Q

Incubatory carrier

A

incubating pathogen but not yet ill

shedding of pathogen during incubation period

41
Q

Strangles in horses

A
  • detection of convalescent carriers
  • contagious febrile disease of URT w abscess of lymph nodes
42
Q

Pathogenicity islands

A

carry genes coding 1 or more virulence factors

  • horizontal gene transfer
  • mobile, located on bacterial chromosome or plasmids
43
Q

Quorum sensing

A

regulates gene expression in response to changes in cell density

Mediated by chemical signal molecules (autoinducers)

Low density= individual cell behavior

High density= group behavior

makes biofilm

44
Q

Virulence factors that play a role in adherence

A
  1. Flagella
  2. Pili/ Fimbriae
  3. Capsule= glycocalyx.. layer of exopolysaccharides
45
Q

Invasion

A

ability of pathogen to spread to other locations in host by invading host cells/tissues

46
Q

Extracellular invasion

A

breaks down barriers of tissue to disseminate in host while remaining outside host cell

Production of extracellular enzymes

47
Q

Intracellular invasion

A

bacteria penetrates cell and survives within enviro

  • Facultative intracellular
  • Obligate intracellular
48
Q

Exotoxins

A

Proteinaceous toxins

Delivery by:
1. Secretion into milieu
2. Direct injection into host cell

49
Q

Type 1 Exotoxin

A
  1. Active @ cell surface
  2. Disturbs cell metabolism by binding to receptors on cell surface

Ex: clostridium perfringens

50
Q

Type 2 Exotoxin

A

damages membranes of cells

Ex: staph aureus

51
Q

Type 3 Exotoxin

A

Intracellar, needs transport protein to be brought in (A-B toxins)

Ex: clostridium botulinum

52
Q

Types of proteolytic toxins?

A
  1. Botulinum toxin
  2. Tetanus toxin
53
Q

Endotoxins

A

component of prokaryotic cell wall, not released until cell death and lysis of bacteria

Effect: fever, diarrhea, weakness, blood coag, septic shock, death

54
Q

(Lipo) Teichoic Acid

A

Only in GRAM +

Mediator of septic shock

55
Q

Does exotoxins have low or high toxicity?

A

High toxicity

56
Q

Do endotoxins have low or high toxicity?

A

Low toxicity

57
Q

Where is the gene location for exotoxins vs endotoxins?

A

Exotoxins= on plasmids

Endotoxins= on bacterial chromosome

58
Q

Heat stability for exotoxin vs endotoxin?

A

Exotoxin= heat labile

Endotoxin= heat stable

59
Q

Are vaccines available for exotoxins or endotoxins?

A

Only available for exotoxins (toxoids)

60
Q

Antigenicity of exotoxin vs endotoxin

A

Exotoxin= highly antigenic

Endotoxin= poorly antigenic

61
Q

What species are exotoxins found in?

A

Both gram positive and gram negative

62
Q

What species are endotoxins found in?

A

Mostly gram neg and Listeria

63
Q

True or false: Endotoxins are part of the cell wall

A

TRUE

64
Q

What is the protein location of exotoxins?

A

Proteins secreted from cell

65
Q

Biofilms

A

Mass of bacteria, clings to surfaces

Produces extracellular polymer matris and exchanges nutrients

66
Q

Functions of biofilms

A
  1. Bacterial persistence (endocarditis)
  2. Reduc. of host immunity
  3. Local damage (Ex: catheters)
  4. Reduced susceptibility to antibiotics
67
Q

Iron uptake

A

needed for bacterial growth

Bacterial cytotoxins damage host by releasing ferritin, hemoglobin, lactoferrin

Receptor mediated recognition