Microbiology > Unit I: A > Flashcards

Unit I: A Flashcards

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1
Q

What is the function of pili

A

Attachment to host cells, other bacteria, or surfaces allowing the infection, colonization, or DNA transfer

mating process in gram-negative bacteria

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2
Q

how does a pilus help spread antibiotic resistance

A

through bacterial CONJUGATION of resistance-carrying plasmids

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3
Q

What bacterial structure is responsible for gonococcus and where in the body

A

pilus; reproductive tract

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4
Q

what is the role of a bacterial capsule

A

important mucoid surface layer endowing resistance to phagocytosis by WBC in many pathogenic bacteria

like a slippery bar of soap

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5
Q

what diseases is the capsule responsible for

A

meningitis, pneumococcal, and Hib diseases

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6
Q

what is Koch’s first postulate

A

the suspected pathogenic organism should be present in all cases of the disease and absent from healthy animals

may be circumstantial

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7
Q

how are Koch’s postulates observed

A

1: observes blood under microscope
2. streak agar plate with sample from either diseased or healthy animal
3. remove blood or tissue sample and observe by microscopy
4. laboratory culture (pure culture recognition)

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8
Q

what is Koch’s second postulate

A

the suspected organism should be grown in pure culture outside of the animal

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9
Q

What is Koch’s third postulate

A

cells from a pure culture of the suspected organism should cause disease in a healthy animal

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10
Q

what is Koch’s fourth postulate

A

biopsy of the animal should re-iosolate the organism grown to be the same as the original

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11
Q

What is transduction

A

DNA transfer via viral infection
like delivery services

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12
Q

what is transfromation

A

DNA uptake by a competent live bacterial cell likely from a dead bacterial cell

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13
Q

What is fimbriae

A

important attachment surface appendage with specific portions that recognize specific targets on the humans cells of the urinary tract

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14
Q

What is flagellum and what does it allow

A

powers motility in surrounding fluids-allows chemotaxis (moving directed movement)

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15
Q

how is the motion of a flagellum denoted

A

T = tumble (3D turn), R = run

if the bacteria is running away from the positive chemotaxis, it will run shorter than it would if it was running towards from the positive chemotaxis

can be used to design anti-infection catheters

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16
Q

how is flagellum related to the immune system

A

it is highly antigenic: recognized by the immune system because it is a long foreign body

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17
Q

What is the cell wall materials made of and why does this matter

A

negative electrically charged material
dyes for bacteria need to be positively charged for it to bind to the cell

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18
Q

what is the use of the cell wall to human observation

A

to classify different types of bacteria: the basis for the Gram stain

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19
Q

what components of the cell wall are not found in human cells that are signals of microbial presence in human bodies

A

Teichoic acid
Lipopolysaccharide (LPS)
Peptidoglycan

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20
Q

What are peptidoglycan for

A

structural support for the cell wall that can be attacked to treat infection

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21
Q

What are the characteristics of a gram-positive cell

A

2 layers
thick cell wall of peptidoglycan and the cell membrane

purple stain

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22
Q

What are the basic characteristics of a gram-negative membrane

A

3 layers
cell wall: outer membrane layer and thin peptidoglycan layer
cell membrane
with more periplasmic space than gram-positive

pink counterstain

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23
Q

Describe gram-positive cell wall

A

Thicker homogenous sheath of peptidoglycan
teichoic acid chains (both peripheral and integral)

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24
Q

What is cell wall teichoic acid

A

polymer of ribotol or glycerol and phosphate embedded in the peptidoglycan sheath

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25
What is the use of the periplasmic space
temporary storage of enzymes maybe peptidoglycan synthesis
26
how is the outer membrane of gram-negative cells different than gram-positive
contains specialized types of lipopolysaccharides (LPS) and lipoproteins linking proteins that can be used for bacterial identification
27
what happens if the lipopolysaccharide lipid portion is released during infections
may cause toxic septic SHOCK because it is an endotoxin where the polysaccharides give rise to the somatic (O) antigen in gram-negative pathogens
28
What are the cardinal signs of septic shock in the human body
elevated WBC tachycardia (fast hr) Tachypnea (fast breathing) Hypotension (low bp) Fever
29
What happens with peptidoglycans in human bodily fluids tear, saliva, breast milk
hydrolyzed by antimicrobial lysozymes
30
what are the 3 protective layers that surround where DNA is located in bacterial endospores
Exosporium spore coats Cortex (precious core DNA)
31
What is an endospores best quality
withstanding hostile conditions (temp, chemicals) and facilitating survival
32
what are endospores
dormant bodies produced by various bacteria with a two-phase life cycle (endospore/vegetative)
33
What do endospores do
act as the infectious entity in botulism (ingestion) anthrax (inhalation) and tetanus (puncture wound) where endospore germination causes disease
34
Why are bacterial shapes important
many bacterial scientific names are based on cell shape identifying bacteria
35
What are the shapes of bacteria
spherical or ball shaped -coccus cylindrical - rod/bacillus gently curved - vibrio spiral-shaped cylinder - spirillum thinner helical/spiral hair width -spirochete branching filaments
36
what are the main factors influencing the arrangement of bacterial cells
pattern of division and how the cells remain attached afterard
37
Describe Bacilli and Coccus arrangement
Cocci have the greatest variety in arrangement (can be grouped liked grapes (staphlo) or chained (strepto)) while bacilli have less varied arrangement because they only divide in the transverse plane
38
how does transformation occur
free ssDNA is integrated into the acceptor and either the original strand or the new resistant DNA will be removed for complementary strands. Then the bacteria will be grown in culture with a antibiotic so that only the antibiotic resistant bacteria will grow useful for recombinant DNA
39
how does transduction occur
bacteriophage serves as a carrier of DNA from a donor to a recipient of the same species
40
what phase occurs in transduction where the DNA is broken down
lytic phase
41
what are the two results of bacteriophage transduction
newly grown bacteriophages with either all viral DNA or some chromosomal DNA
42
what are the three ways that leads to genetic recombination and acquisition of new traits
conjugation transduction transformation
43
where is fimbriae used in the human body
as a uropathogeneic E. coli to colonize the urinary tract resulting in UTI
44
what would happen if fimbriae of a urobacteria bind to the sugar mannose
fimbriae would not be able to bind to the urinary tract cells and would not travel up through the urinary tract
45
what is the significance of the cell wall
helps the bacteria shield from unfriendly things is antigenic for the human body that will be easily recognized
46
what does the cell envelope contain
the cell wall periplasmic space cell membrane
47
describe the gram-negative cell wall
no teichoic acid has lots of lipopolysaccharides in outer membrane layer lipoprotein that links the outer membrane and the peptidoglycan
48
what inhibits peptidoglycan synthesis
B-lactam antibiotics/penicillin type antibiotics
49
why are lipopolysaccharides aka endotoxins the leading cause of death in hospitals,
lowered blood pressure to vital organs leading to organ failure Septic (bacteria in blood) shock
50
why is death to the microbe to treat septic shock not enough
the LPS is still roaming the blood the high blood pressure is a problem
51
what does a vasopressor do
more volume because of septic causes constriction to increase BP to provide adequate blood to vital organs
52
why is it necessary to regulate the nervous system in sepsis
the NS becomes a central driver of organ failure causing inflammation and disrupting autonomic signals which affects the heart and blood vessel function overactivates sympathetic and inhibits parasympathetic
53
describe modulation of the septic response
inject LPS antibodies into blood. goes through liver, and gets filtered
54
How are teichoic acid and peptidoglycan similar to LPS
similar issues to LPS but 100x less potent
55
what is the O-antigen
variable region (found in LPS) that varies between species variable areas act as a tool to identify bacteria
56
if blebs are formed in the gram-positive cell wall, what is the most likely target of the bioweapon
it is the most common component of the cell wall
57
what is the agent of transmissible disease
the free spore that find favorable conditions in human body becoming a vegetative cell
58
what is the phase where an endospore breaks dormancy
germination
59
how does an endospore enter the vegetative phase
germination in the presence of water and a germinating agent signals hydrolytic enzymes that digest the endospore membrane. The endospore core rehydrates and grows out of the endospore coats. Then it can infect
60
Describe the permeability of the gram-negative cell wall
makes bacteria more antibiotic-resistant and nutrient-resistant due to the permeability layer it has porins to combat this and let in nutrients
61
what is the cell membrane
a thin sheet of lipid and protein that surrounds the cytoplasm and controls the flow of materials into and out of the cell pool
62
what is the bacterial chromosome or nucleoid
condensed DNA molecules containing essential genetic info of cell and codes for all proteins
63
whatis the s layer
monolayer of protein used for protection and/or attachment
64
what is the outermembrane
contains lps. controls flow of materials portions are toxic to mammals when released
65
what is the cell wall
semirigid casing that provides structural support an shape for the cell
66
what is the capsule
coating of molecules external to the cell wall serves protective, adhesive, and receptor function
67
what are inclusion/granule
stored nutrients such as fat, phosphate, or glycogen deposited in dense crystals or particles that can be tapped into when needed
68
what is the plasmid
small double stranded DNA molecule containing extra genes
69
what are mycobacterium
genus of rod-shaped, aerobic bacteria characterized by unique waxy cell wall rich in mycolic acids
70
who discovered tuberculosis
robert koch
71
what are the four steps of the gram stain
crystal violet: primary stain Grams iodine: mordant (stabilizes the primary stain) acetone: decolorizer safranin: counterstain
72
why would an older culture stain gram negative
aging bacteria lose their ability to retain the primary dye, crystal violet
73
why might over decolorized cells appear gram negative
because excessive exposure to alcohol or acetone breaks down the cell wall causing gram-positive bacteria to the lose the primary crystal violet-iodine complex
74
What is the lipoprotein
linking protein in the gram-negative cell embedded in the outer membrane holding the cell wall in close proximity to the periplasmic space
Microbiology
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