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I&I > Microbiology: A Focus on Bacteria, Fungi, and Viruses > Flashcards

Microbiology: A Focus on Bacteria, Fungi, and Viruses Flashcards

1
Q

How do “bad” pathogens arise from human microbiome

A

dietary changes
stress
antibiotics

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2
Q

True/false: Majority of pathogens are non-pathogenic

A

true

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3
Q

What do pathogens do to help them survive?

A

They constantly evolve by either losing or gaining traits over time

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4
Q

What is the incubation period

A

The time it takes the pathogen to enter the body and show the first symptom to appear

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5
Q

What does the incubation period depend on

A

health of host
growth rate of pathogen
degree of exposure

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6
Q

What is the timeline of infection

A

incubation period –> onset of illness –> period of invasion –> convalescent period

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7
Q

What are the different types of infections

A

Acute
Chronic
Latent (persistent)

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8
Q

What is an acute infection

A

Symptoms develop quick
Clears quickly
Host has immunity for reinfection
ex. strep throat

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9
Q

What is chronic infection

A

Symptoms develop slowly
Can last months to years
ex. tuberculosis

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10
Q

What is latent (persistent) infection

A

Illness never goes away
It becomes formant in the body and can be awakened with low immunity
ex. syphilis, typhoid, fever, etc.

Carriers: the host may not show symptoms but they spread it to others

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11
Q

What is horizontal transmisson

A

person to person (horizontal)
ex. blood, saliva, stds, urine

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12
Q

What is vertical transmissoin

A

Mother to baby via breast milk, delivery, placenta

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13
Q

What is a vector

A

An animal or arthropod that caries a pathogen and can transfer it to humans
ex. rabies virus transmitted by animal bite

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14
Q

What is virulence?

A

the degree of pathogenicity of a pathogen (bacteria, fungi, or virus) and is determined by its ability to invade and multiply within the host causing disease

They grow and thrive at the expense of the host

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15
Q

what is a strict pathogen

A

always causes disease

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16
Q

What is an opportunistic pathogen

A

part of normal microbial flora
takes advantage of a weakened immune system
caused by the disruption in the microbial flora
breached barrier introduced by a wound

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17
Q

Bacterial Characteristics shapes

A

Maintained by cell wall of bacteria composed of peptidoglycan

No nucleus –> chromosome forms a structure called a nucleoid

No membrane-bound organelles (prokaryotic)

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18
Q

What are the main shapes of bacteria

A

cocci
bacilli
spiral
pleomorphic (no defined shape)

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19
Q

What is the cocci shape

A

Spherical bacteria

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20
Q

What are the different variations of cocci?

A

Single organisms (cocci)
Pairs (diplococcus)
Chains (streptococcus)
Clusters (staphylococcus)
Tetrads
Sarcina (cube of eight cocci)

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21
Q

What is bacilli

A

Rod shape

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22
Q

What are the variations of bacilli

A

Single (bacilli)
Double (diplobacilli)
Chain (streptobacili)
Palisades

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23
Q

What is the intermediate shape between coccus and a bacillus

A

coccobacilli

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24
Q

What are the shapes of spiral bacteria

A

Vibrio
Spirillum
Spriochete

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25
What is vibrio
curved or comma-shaped rod
26
What is spirllum
Thick, rigid spiral
27
What is spirochete
thin, flexible spiral
28
What is pleomorphic
do not have any characteristic shape can change their shape also can be a combination of shapes
29
What cell retains crystal violet from iodine
gram +
30
What cell does not retain crystal violet and appears transparent
gram -
31
Which cell has a thick multi-layered peptidoglycan layer
gram +
32
Which cell structure contains lps
gram -
33
What is LPS
only produced by gram (-) Consists of lipid and carbohydrate Helps bacteria cause disease
34
What are cell wall components
LPS (only in gram -) and peptidoglycan (sugar and amino acids)
35
which cell type has an outer membrane that prevents crystal violet penetration
gram (-)
36
Which cell develops resistance more quickly
gram (-)
37
Which cell is more resistant to antibodies due to impenetrable cell wall
gram (-)
38
Which cell lacks peptidoglycan
gram (-)
39
What are acidophiles
bacteria that grow optimally at pH values around 2
40
What are alkalophiles
only grow well at pH values near 10
41
Aciduric (acid tolerant)
Can survive acidic conditions but not necessarily grow under those conditions
42
Psychrophiles
Prokaryotes that grow very poorly at temperatures above 15 celcius
43
Thermophiles
thrive at 100 degrees C
44
What are the components of a bacterial cell structure
Capsule Cell wall Cytoplasmic membrane Pili Flagella Nucleoid Cytoplasm Ribosomes
45
What is capsule
covers the outer layer of the cell wall composed of polysaccharides mediates attachment of bacterium to host tissues can inhibit phagocytosis by neutrophils and macrophages --> virulence factor for some bacteria
46
Strep mutans
one of the causative agents of dental caries attaches to tooth surfaces via a capsule
47
What is slime layer
some bacteria have a loosely adherent colloidal material that they secrete usually similar to the capsule
48
What is a pili (aka fimbriae)
Extend from cell surface Pili: long hair-like tubular microfibers Responsible for: attachment and transfer of DNA & motility only in gram (-) only!!
49
What is the flagella
extend from interior cell body Responsible for: motility, also sense certain temperature and chemicals/metals present in both gram + and -
50
Bacterial Growth Curve phases
lag phase --> exponential (log) phase --> stationary phase --> death phase
51
What is the lag phase
initial phase characterized by cellular activity BUT NOT GROWTH cells increase in size, but no cell division
52
Exponential (log) phase
cells divide by binary fissions & metabolic activity high
53
Which bacteria growth phase are antibiotics and disinfectants most effective in?
Exponential (log) phase
54
Stationary phase
Bacterial cell growth reach a plateau Number of dividing cells equal the number of dying cells No overall population growth
55
Death phase
Number of living cells decreases exponentially Population growth experiences sharp decline
56
Bacterial spores
gram (+) bacteria only form spores especially under adverse environmental conditions
57
What is the importance of spores
structure of spore protects its DNA from intense heat, radiation, and attack by most enzymes and chemical agents So resistance to environmental factors --> can exist for centuries Difficult to decontaminate with standard disinfectants or autoclaving
58
Aerobic bacteria
require oxygen for basic survival, growth, and reproduction
59
Anaerobic
don't require oxygen for growth
60
Fermentation
Anaerobic conditions only Conversion of pyruvate to various end products (ethanol and lactic acids)
61
True/false: aerobic and anaerobic conditions both involve glycolysis
True
62
Which cell has peptidoglycan and what does peptidoglycan do
gram (+) Induce fever/inflammation
63
What does LPS do? (low vs. high doses)
Low doses: activates immune response and triggers fever High doses: extreme fevers, septic shock, skin lesions (fatal)
64
Two ways bacteria cause disease
release of exotoxins bacteria inhibit phagocytosis of immune cells
65
release of exotoxins (polypeptides)
receptor-binding proteins that cause cell death or change in function Cytolysis bursting of host cell from osmotic pressure
66
What type of bacteria releases exotoxins
gram - and gram +
67
What do exotoxins do
releases: enzymes, gas, acids, toxins toxins: cause cell lysis and can cause degradation of tissue by immune response Can be encoded on a plasmid or a bacteriophage
68
Transformation
introduction, uptake and expression of foreign genetic material
69
Conjugation
Transfer of DNA via plasmid from a donor cell to a recipient cell Involves pilius
70
Transduction
bacterial DNA is moved from one bacterium to another by a virus
71
Quorum sensing
bacteria's way to communicate
72
Fungi
diverse group of free-living eukaryotic micro organnisms may be unicellular or multicellular
73
Fungi in our body
controlled by competent immune system and multiplies when conditions are favorable
74
obligate intracellular parasites
viruses
75
Are viruses alive
me dont think so because" do not reproduce, do not maintain metabolism to gain energy on their own
76
Different virus structures
Naked capsid virus or enveloped virus
77
What is naked capsid virus (non-enveloped)
typically more virulent usually cause host cell lysis cell lysis= most common exit mode from host cell Does not have extra lipid membrane Antibodies are generally sufficient for protection against these infections
78
True/false: Non-enveloped capsid virus is more resistant to extreme pH, heat, dryness, and simple disinfectants
true yuhh
79
How does naked capsid virus spread
spread on fomites, hand to hand, and by small droplets
80
Where can naked capsid virus grow
can survive in the gastrointestinal system because of their resistance to low pH and bile detergents
81
Characteristics of enveloped virus
typically less virulent don't always cause cell lysis during cell exit contain an outer membrane that surrounds the capsid --> can use host cell membrane itself to assemble their membrane --> process avoids cell lysis and helps enveloped viruses escape from host's immune system
82
Which type of virus is relatively less sensitive to environmental conditions
enveloped virus
83
what virus can spread in large droplets and secretions or by organ transplantation and blood transfusion
enveloped virus
84
Virus classification is based on
size, morphology, nucleic acid, disease they cause, means of transmission
85
Morphology of a virus is based on
size and shape
86
Chemical composition and mode of replication
may consist of DNA or RNA may be single or double stranded may be linear or circular
87
Characteristics of DNA viruses
mostly double stranded replication occurs in the nucleus has to be transcribed prior to being synthesized into proteins Exception: a few DNA viruses can replicate in cytoplasm because they carry polymerases DNA --> RNA --> mRNA --> proteins
88
Characteristics of RNA viruses
Mostly single stranded replication occurs in the cytoplasm can use its RNA to immediately synthesize proteins RNA --> mRNA --> Proteins
89
What is a positive strand of RNA
RNA virus that serve as mRNA and can immediately be translated into proteins RNA/mRNA --> proteins
90
What is a negative strand of RNA
Viral RNA must first be transcribed into mRNA then can be translated into proteins RNA --> mRNA --> proteins
91
What are retroviruses
reverse normal transcription reverse transcriptase will transcribe the RNA from the virus into DNA and then incorporates it into the host's cell DNA <-- RNA
92
Viral Replication APURAM
study on slides for more detail lol Attachment Penetration Uncoating Replication Assembly Maturation Release

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