Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology > 01 - Intro to Microbiology > Flashcards

01 - Intro to Microbiology Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Symbiotic organisms live in close nutritional relationships between what two things?

A

microorganism and host

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Between the host and microorgansim which one normally provides nutrients so the other can live?

A

the host provides to microorganism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

T/F: host is always human

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In commensalism is the host harmed or benefited?

A

the host is neither harmed or benefited

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is an example of commensalism?

A

the micro bacteria in our ears; no harm no benefit

- only live there because its warm and dead cells provide nutrients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is an example of commensalism?

A

the micro bacteria in our ears; no harm no benefit

- only live there because its warm and dead cells provide nutrients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Within mutualism who benefits?

A

both members benefit; stronger/better

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Within mutualism is it more or less difficult for other organisms to grow?

A

more difficult

- ex ecoli provides vitamin K and protect us from other organisms in order to defend their own territory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Within a parasitism relationship who is dependent and who benefits?

A

parasitic microbe is dependent on host and benefits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

In parasitism does it describe to us the organism or the relationship?

A

it describes the relationship

- does not tell us the organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How do HCP act as vectors?

A

transmitting mircroorganisms to patients, coworkers and others

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

In what two ways does bacteria show?

A
  • prokaryotic

- eukaryotic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Characteristics of prokaryotic

A
  • alive
  • no nuclei
  • single celled
  • live singly, in pairs or clusters (bacteria dependent)
  • can cause significant infection to humans
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How to treat a prokaryotic infection

A
  • way more antibiotics for antiviral and antifungal

- can tell difference because we are eukaryotic and that way they can find a way to target (antibiotics)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Characteristics of eukaryotics

A
  • bacteria very different from us

- lots of targets that we can attack to develop antibiotic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Adverse effects of antibiotics are usually associated with and why?
Symptoms

A

the gut as the antibiotic kills normal flora

- cramping, diarrhea, bloating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which signs or symptoms are more severe between viral and bacteria

A

signs and symptoms from bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Characteristics of viruses

A
  • acellular
  • not alive
  • not visible by light microscopy
  • ## genetic material surrounded by protein coat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

t/f: with viruses we tend to get better on our own

A

true

- immune response to viral pathogen is slower and signs and symptoms are not as severe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Are fungi eukaryotic or prokaryotic

A
  • eukaryotic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

characteristics of fungi

A
  • eukaryotic
  • have nuclei
  • cell wall
  • organelles
  • obtain nutrients from other organisms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What element of fungi is used as a target for pharm therapy?

A
  • cell wall
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Characteristics of protozoa

A
  • eukaryotic
  • single celled
  • possess a nuclei
  • eg. parasites
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Characteristics of helminths

A
  • eukaryotic
  • multicellular
  • possess a nuclei (visible with a naked eye)
  • eg. worms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Most infections associated with protozoa and helminths are associated with issues of?

A

sanitation; do not see these as often

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

If someone has travelled what should you expect?

A

parasite

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What are the only microbes that we can visually see at certain points in life cycle

A

Helminths

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Bacteria- typical structure

A
  • generic bacteria is rod shaped
  • no nuclei
  • prokaryotic
  • cell walls are important target to classify bacteria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Bacteria Characteristics

A
  • no nucleus
  • have smaller separate circles of DNA known as plasmids
  • ribosomes smaller than those of eukaryotes
  • cell wall and cell membrane
  • external cellular structure such as a flagella or pili
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Plasmids

A
  • Encode specific factors for organism
  • they can be shared with other bacteria
  • Train other bacteria to be resistant to it
  • FINISH full dose of antibiotics → eliminate all microorganisms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

In single celled organisms what can also be targeted for pharm therapy?

A

ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

The cell wall in prokaryotes are either

A

gram positive or gram negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is an example of a bacteria resistant to antibiotics and why?

A

MRSA

  • Resistant to penicillins
  • It has plasmid that tells it how to work around penicillin
  • Penicillin cannot work against bacteria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Bacteria classification: cell morphology

A 
●	Shape
●	Arrangement
●	Colony morphology
●	External structures
●	Capsules
●	Spore formation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Bacteria classification: cell wall structure

A

● Staining and microscopy
● Gram and acid fast (TB) stains
○ Determine if it is a gram positive or gram negative cell wall
○ Helps to determine diagnosis/treatment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Bacteria Classification: growth characteristics

A

oxygen and energy requirements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Bacteria Classification: Metabolism

A
  • carbohydrate utilization and fermentation products
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Bacteria Classification: molecular techniques

A
  • dna sequencing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Cell morphology

A

● Wide variety in morphology can be identified by direct examination
○ Shape, size, arrangement, presence of spores or capsules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Cell morphology: diplococci

A
  • attached to one another
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Cell morphology: cocci

A

means organism is round

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Cell morphology: streptococci

A

means the organism is in pairs or chains; always round

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

cell morphology: staphylococci

A

means bunches; always round

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

cell morphology: bacilli

A

rod shaped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

cell morphology: coccobacilli

A

little bit rod and round

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Bacteria: Colony morphology

A 
●	Characteristics of colonies grown on agar plates = identification
For identification: 
●	Shape (form) of the colony
●	Margin/edge
●	Elevation
●	Surface texture
●	Pigmentation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Bacteria External Structures: Flagella

A
  • Protein filaments that extend from the cell membrane
  • Motile (rotate 360°)
  • Allowing microbe to move in a series of tumbles
  • Runs in response to stimuli (light, nutrient density, etc…)
  • Move from low nutrient density to high nutrient density
  • Bacteria w/flagella have high capacity to make us sick
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Number and location of flagellum can be used to classify microbes

A

● Polar – Vibrio spp. (single)
● Spirillium spp. (double)
● Peritrichous – Escherichia coli spp (tons of flagella)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Bacteria External Structures: Fimbriae

A
  • Straight filaments arising from bacterial cell wall
  • Facilitate movement
  • Used to “pull” the bacterium across a substrate
  • Not used for propulsion
  • Facilitate formation of biofilms
  • Shorter than flagella
  • Act as adhesins
    Bind to specific host cell receptors
  • Important role in adherence, a critical step in infection
  • E. coli spp. & Campylobacter jejuni bind to intestinal epithelial cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Bacteria External Structures: Conjugation Pili

A
  • Used to transfer DNA from one bacteria to another
  • Facilitate movement of plasmids
  • Share with other bacteria making them resistant to antibiotics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Bacteria External Structures: Glycocoalyx

A
  • two different forms of the same thing
  • Protective substance surrounding some bacteria
  • Normally made of polysaccharides
  • Presence/absence can be used for classification
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Slime Layer

A
  • Sticky and loose
  • Prevents dehydration
  • Allows bacteria to bind to surfaces
  • Form a protective layer encapsulating colonies of bacteria
  • Good at holding onto inorganic material
    ○ Prosthetics
    ○ Catheters
    ○ Replacements (hip, heart valve → must all come out)
  • Difficult to penetrate with antibiotics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Capsule

A
  • Firmly attached to cell surface
  • Specific to one bacteria
  • Virulence factor that facilitates adherence and impairs phagocytosis
  • Better at making us sick
    ○ With capsule → highly correlated with severe pneumonia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Endospores

A
  • Defensive strategy against hostile or unfavorable environmental conditions
  • Driven by nutrient supply
  • Spores are not responsive to normal cleaning practices
  • Metabolically dormant - resistant to heat, cold, drying, chemicals and radiation
  • Germinate when conditions improve
  • Excellent defensive strategy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What forms endospores

A

Formed by two genera: Clostridium spp. and Bacillus spp.
● Requires special environmental controls to kill spores
● Cleaning and disinfecting techniques are not sufficient
● Sterilization is required
○ Steam, under pressure, chemical sterilants, etc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What makes up the bacteria cell wall structure?

A
  • peptidoglycan layer
  • not observed in human body
  • makes it easy to identify and get rid of it
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

t/f: different types of cell walls can be used to classify species

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Bacteria Cell wall characteristics

A

● Provides cellular structure and shape
● Counters the effects of osmotic pressure
● Provides rigid platform for external appendages
○ Allows flagella, fimbriae to anchor
● Facilitates adherence to host cells & evasion of host defenses
● Target for antibiotics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Gram Stain identifies

A

two types of bacteria cell wall known as positive or negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Gram positive

A
  • bacteria retain primary dyes and become a purple colour post-Gram Stain
  • Thick, dense, non-porous cell walls
  • Do not possess an outer membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Gram Negative

A
  • bacteria easily decolorized and take on a pink/red colour post-Gram Stain
  • Thin cell wall surrounded by outer membrane
  • The outer membrane contains Lipid A; polysaccharide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Lipid A

A
  • is a pathogen associated molecular lipid protein
    ○ Component of foreign agent
    ○ Our body responds to it immunologically
    ○ Even though we don’t have any direct contact/history with pattern/protein
    ○ Every human is born with an immune system that recognizes Lipid A as foreign
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Dye retention is dependent on

A
  • thickness, density, porosity, integrity, and chemical composition of cell wall
  • The Gram Stain is starting point for bacterial identification
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Community is more associated with what type of gram

A

gram positive organism

● More frequently infected with gram positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Hospital and long term care are normally associated with what type of gram

A

more associated with gram negative organisms

66
Q

t/f: Some non-bacterial organisms with thick cell walls may also stain Gram-Positive

A

true

○ Some yeasts may absorb gram stain

67
Q

Gram-Positive bacteria that have lost wall integrity through aging or damage may stain

A
  • gram negative
  • They should hold onto the crystal violet iodine → they CANNOT
  • Usually b/c they are physically or chemically damaged
  • Actual bacteria are dying
  • Occurs due to poor sampling technique
68
Q

t/f: not all bacteria will gram stain

A

true; specialized stains are required for some species

69
Q

Do gram negative and positive have different or the same susceptibility to antibiotic drug classes?

A

different

70
Q

Two Microorganisms causing respiratory infection

A

Staphylococcus aureus and streptococcus pneumoniae

71
Q

What are the first immune cells recruited in bacterial infections?

A

neutrophils; see them u can confirm bacterial infection

72
Q

Gram Negative organism

A

● Diplococci

● Neisseria gonorrhoeae

73
Q

Acid Fast Stains

A

Most bacteria do not retain dye carbol fuchsin after treatment with acidic alcohol

74
Q

Acid Fast stains example

A

● Mycobacterium species do not dye from gram stain
○ e.g. Mycobacterium tuberculosis
● They contain a waxy material (mycolic acids) in their cell wall
○ This retains the stain
○ They are not good at absorbing the gram stain

75
Q

When are acid fast stains used specifically?

A

specifically when mycobacterial infections are suspected
● Not performed on all samples
● Needs to be requested

76
Q

Enzymes that bacteria use to detoxify reactive oxygen products include:

A

● Catalase
● Peroxidase
● Superoxide dismutase

77
Q

t/f: how bacteria use oxygen is not useful for classification

A

false; it is useful

78
Q

T/F: bacteria can be classified according to their stability to tolerate oxygen

A

true: Whether or not they like/hate oxygen has to do with their internal capacity to deal with free radicals and oxidative stress

79
Q

Molecular oxygen is highly reactive and toxic to bacteria unless:

A
  • Its inactivated by enzymes produced by bacteria

- Enzymes neutralize the free radicals

80
Q

Produce all three enzymes

A

large capacity to live in oxygen rich environment

81
Q

None of three enzymes

A

need to live somewhere with absolutely no oxygen

● Deep tissue wounds

82
Q

Oxygen Requirement: obligate aerobes

A

● Require oxygen to survive
● Possess all 3 enzymes
● Obligate → obligation to live in oxygen rich environment

83
Q

Oxygen Requirements: Facultative anaerobes

A

facultative = flexible
● Prefer to grow in the presence of oxygen
● Can also grow without
● Produce catalase and superoxide dismutase

84
Q

Oxygen Requirements: microaerophiles

A

● Tolerate low amounts of oxygen
○ i.e.: stomach
● Produce superoxide dismutase

85
Q

Obligate Anaerobes

A

● Cannot tolerate oxygen
● Lack enzymes to manage it’s toxicity
● Requires special growth conditions

86
Q

Why two blood culture specimens are required from each venipuncture site - one aerobic, one anaerobic!

A

● Lab needs to test in oxygen and without oxygen
● They won’t have enough if there is only one vial given
● Take two sets of two
○ 2 bottles from aerobic
○ 2 bottles from anaerobic

87
Q

Bacteria Reproduction: A sexual Reproduction

A

binary fission
# of cells increase exponentially when nutrients are readily available
● Exponential growth phase
● Amount of nutrients is less available → enter stationary phase

88
Q

T/F: doubling time differs by species and conditions

A

true

  • E. coli doubles every 20 min
  • Mycobacterium spp. double every few days under optimal conditions
89
Q

Stationary Phase

A

Nutrients are depleted + toxic wastes accumulate → rate of growth slows to a stationary phase
● Without new source of nutrients = bacteria begin to die
● Death phase
● Can occur with poor sampling technique, preparation, and travel times

90
Q

Reproduction: When transferred to a new environment

A

● Enter lag phase

● Pathways required to utilize nutrients are reactivated

91
Q

Reproduction: Sexual Reproduction

A

reproduction (requires conjugation pili)

● Do not see this as frequently

92
Q

Intracellular bacterium: Obliate intracellular bacteria

A 
●	Require host cell to live
●	Cannot make their own energy
●	Grow and reproduce inside the host cell
○	 e.g. Chlamydia spp.
●	Require cell cultures for growth in laboratory
○	Cannot grow on agar plate
○	They have to grow on tissue culture
○	Have to infect tissue to survive
93
Q

Facultative intracellular bacteria

A

● Can live in host cells if needed
● Capable of getting their own energy required to live too
● Able to survive phagocytosis
● Grow and reproduce within immune cells (macrophages, neutrophils)
○ Outsmart macrophage
○ Do not die when phagocytosed by immune cells
○ e.g. Neisseria spp.
● Shielded from antibodies and other immune defenses
○ Contributes to their ability to survive illness
● Employ specialized mechanisms to protect against lysosomal enzymes in host cell
● They are able to grow on agar plate

94
Q

Viruses

A

● Very few antiviral medications
● Rely on immune system to take care of virus
● We can only provide supportive measures

95
Q

Are viruses alive? What are they wrapped in?

A
  • no: acellular not alive
    ● They are a bit of genetic material
    ○ Either DNA or RNA wrapped in capsule
96
Q

Obligate intracellular pathogen

A

● Cannot replicate (multiply) independently
● Must replicate inside host cells
● Using enzymes, organelles and energy from the host cell to increase in number

97
Q

Acellular; lack cell membrane, composed of only a few organic molecules

A

● Possess DNA or RNA

● Supported by a protein capsule or “capsid”

97
Q

Acellular; lack cell membrane, composed of only a few organic molecules

A

● Possess DNA or RNA

● Supported by a protein capsule or “capsid”

98
Q

Viruses: Capsule

A

○ Protection

○ Provide recognition sites that bind to receptors on host cells

99
Q

Viruses: Envelope

A
  • Some viruses also possess an “envelope” derived from host cells
  • Leave host cell and drag host cell with them
  • Facilitates entry into host cells
  • Cellular membrane proteins are replaced with virus-derived proteins
100
Q

Characteristics used to define viruses include:

A

● Virion structure
● Mechanism of replication
● Nature of genome
● Molecular techniques ***

101
Q

Virus Classification includes more detailed division includes consideration of:

A

● Host and tissue range, cytopathic effect on host cell
● Nature of disease
● Serological reactions
○ Draw blood and look for antibodies
● Amino acid sequences of viral proteins, nucleic acid sequences

102
Q

Viral Replication

A

● Replicate in linear process
● Cannot reproduce independently
○ Nothing until all the viruses have left the cell
○ People feel bad and then all the sudden feel like trash
○ Little viral load → lots of viral load
● Lack enzymes necessary for replication
● Do not possess ribosomes for protein synthesis
● Once under control of a viral genome, host cell is forced to replicate viral genetic material and translate viral proteins

103
Q

Viral Replication Cycle in Host Cell: Attachment

A

Specific molecular interaction with a host cell receptor

104
Q

Viral Replication Cycle in host cell: Entry

A

Entry via direct penetration, membrane fusion, or endocytosis

  • Uncoating; required for viruses that enter the host cell with their capsid intact
  • Capsid is removed
105
Q

Viral Replication Cycle in host cell: Synthesis

A

● Strategy varies depending on nucleic acid (ie; DNA, RNA, ds, ss)
● DNA synthesis occurs in nucleus
● RNA synthesis in cytoplasm

106
Q

Viral Replication Cycle in host cell: Assembly

A

Once components are synthesized → assembled into virions

107
Q

Viral Replication Cycle in host cell: release from host cell

A

Budding
○ Leave host cell keeping it intact
○ Drag host cell membrane creating viral envelope
○ Enveloped viruses are released via budding
Exocytosis
○ Leave host cell keeping it intact
○ Does not take any cell membrane
Lysis
○ Naked virus released via host cell lysis
○ Destroying the host cell
○ Tear cell open to make its way out to infect other tissues
○ MOST VIOLENT

108
Q

Viral Infection Host cell fate: Aborted viral infection

A

● Body has seen this type of infection before → memory cells at work
● Little or no detectable effect
● Eliminate before any symptoms/signs

109
Q

Viral Infection Host cell fate: Persistent infection

A

● Alteration of antigenic specificity of cell surface
○ Due to presence of virus glycoproteins
● Host cell function is intact leading to gradual prolonged release of progeny viral particles
● Consistent and chronic viral illness

110
Q

Viral Infection Host cell fate: Latent infection

A

herpes, chicken pox, shingles
● Acquires virus → active infection → undergo latency period
○ No more symptoms
● Persistence of viral genome in cell with no virus progeny produced
● Latent virus can be reactivated months to years later (stress, age, friction on skin)
● Resulting in a productive infection
● Cannot cure = can only prolong latency periods

111
Q

Viral Infection Host cell fate: Transformations

A

cervical, penis, anal, and throat cancers
● Integration of viral genome into host cell chromosome
○ Cause fatal mutations
○ Leading to cancer
● Disruption of host cell metabolic functions including cell growth and replication
○ Resulting in the induction of tumours

112
Q

Viral Infection Host cell fate: Cell death

A

rapid lysis of host cell and release of progeny

113
Q

Fungi

A

● Grow as single cells (yeast) or as multicellular filamentous colonies (molds)
● Most are not pathogenic
● They are saprophytic
○ Obtain food from dead organic matter
● Classified and identified based on their characteristic structures, colors, habitats, carbohydrate utilization, modes of growth and reproduction
● In lab → fungi are identified by direct examination/cultured to examine their characteristic structures

114
Q

saprophytic

A

Obtain food from dead organic matter

114
Q

saprophytic

A

Obtain food from dead organic matter

115
Q

Fungal Structure: Yeast

A

● Single cells

● Reproduce via budding

116
Q

Fungal Structure: Molds

A

● Multicellular filamentous colonies, called hyphae
● A mat of overlapping hyphae are called mycelia
● Reproduce via asexual spore formation
● Spores germinate to generate new organisms once an ideal environment is found

117
Q

Fungal Structure: Dimorphic Fungi

A

● Capable of growing in both forms (yeast & mold)
○ Mold out in environment
○ Yeast inside the host
● Reproduce via asexual spore formation
● Spores germinate to generate new organisms once an ideal environment is found

118
Q

Fungal Reproduction: Hand looking structure

A
  • yeasts, unicellular, budding
119
Q

Fungal reproduction hyphae

A
  • molds, hyphae, spores
120
Q

Fungal cell walls composed of chitin

A

● Antimicrobial drugs that target the bacterial cell wall will have no effect on fungi
● Fungi DON’T have peptidoglycan (this makes up bacteria cell wall)

121
Q

Fungal cell membrane contains ergosterol

A

● Limited number of drugs that target the differences between fungi and mammals
○ Cholesterol found in mammalian cell membranes
● Many antifungal cause difficult to tolerate adverse effects

122
Q

Fungi vs Bacteria vs Other Eukaryotes

A
  • Fungal cell membrane contains ergosterol

- Fungal cell walls composed of chitin

123
Q

Fungal Infections: Mycoses

A

● Chronic fungal infections
○ Pathogens grow very slowly
● Classified into 5 groups depending on tissue involved and mode of entry

124
Q

Mycoses: 1. Superficial Infections

A

● Outermost layer of skin, nails and hair (superficial)

● Treated topically

125
Q

Mycoses: 2. Cutaneous Infections (ringworm, tinea)

A
  • Keratinized layers of the skin, hair and nails
  • Ringworm or athlete’s foot
  • Caused by dermatophytes
  • Host immune response may be stimulated
  • Itchy, scaling skin that may become inflamed
  • Transmission human to human (or animal to human) via infected skin
  • Topical therapy may not be sufficient
  • Especially in later stages or when nails are involved
  • Too deep = require oral medication
126
Q

Mycoses: 3. Subcutaneous Infections

A

● Do not see frequently in Canada
○ More in developing countries
● Involve the dermis, subcutaneous tissues, muscle and fascia
● Most infections are chronic
● Expressed clinically as lesions on the skin surface
○ Initiated by trauma to the skin
● Difficult to treat
● Surgical excision or amputation often required

127
Q

Mycoses: 4. Systemic Infections (primary infection)

A 
●	Originate primarily in the lungs
●	Travel to distal sites
●	Fungi found in soil and feces of birds and bats 
●	Geographically defined
○	Associated with inhaled spores
128
Q

Mycoses: 5. Opportunistic Infections

A

● Observed in individuals with impaired host defenses

● Alteration of normal flora, AIDS, DM, immunosuppressive therapy, cancer

129
Q

Parasitic infections

A

Parasitic → protozoa and helminths

● Different than PARASITISM

130
Q

Parasites

A
  • Most common in developing or tropical regions
    ○ Sanitation is poor
    ○ Control of vectors is limited
  • At some point in life-cycle have a microscopic phase
    ○ Require microscope to observe them
  • Throughout the world ~70% of humans are infected with a parasite
  • Parasitic infections are long and chronic
    ○ Sometimes they are very serious
    ○ Especially in immunocompromised patients
131
Q

Protozoa

A
  • Eukaryotic
    ○ Antimicrobials can be associated with toxicity in humans
  • Unicellular
  • Lack a cell wall
  • All exist in a motile, feeding “trophozoite” stage
    ○ Active
    ○ Moving, growing, and reproducing
    ○ Cause active disease in individual
    ○ They will become symptomatic
  • Many protozoa revert to a hardy, dormant “cyst” stage
    ○ Hibernating
    ○ Thick capsule and a low metabolic rate
    ○ Protects parasite from poor environmental factors
    ○ Infective form
    ○ This is the form we find it in the environment
132
Q

Protozoa Classification: Site of infection

A

● GI and urogenital tracts
○ STIs associated with protozoa
● Blood and tissues

133
Q

Mode of iocomotion

A
  • categorize them based on how they move on a wet mount slide
  • Protozoa have different ways of moving
  • Some have any of the following
134
Q

Amoebas

A

● Move by extending cytoplasmic projections outward from main body
● Use pseudopods to move themself along the slide

135
Q

Flagellates

A

● Whip-like projections rotate and propel the organism

136
Q

Ciliates

A

● Hair-like projections cover cell-surface and beat in unison to move cell forward

137
Q

Sporozoa

A

● Generally non-motile

● Adult males sometimes have flagella

138
Q

Nucleotide sequencing →

A

yields more rapid results

139
Q

Protozoa → Reproduction

A

● Typically asexual
○ Binary fission
● Some reproduce by meiotic (sexual) division

140
Q

Protozoa → Reproduction: Vector

A

○ Protozoa is contained within organism that interacts w/us to transfer protozoa into our blood
○ Mosquitoes, tsetse fly, rats

141
Q

Protozoa → Reproduction: Intermediate Hosts

A

○ Snails, pigs, beef, fish

142
Q

Protozoa typically gain access to human host via :

A

● Ingestion or penetration of anatomical barrier (ie: insect bite)
● Followed by attachment, replication, and host damage as organism is released from host tissues

143
Q

Helminths

A

worms

144
Q

Flatworms → tapeworms

A

● Thin, soft body that is flattened dorsoventrally

○ They are squished

145
Q

Two Broad Categories of Flatworms:

A

Trematoda:
● Flukes
○ Liver, blood and lung flukes
● All are parasitic

Cestoidea:
● Tapeworms
○ Beef, pork, and fish can all posess tapeworms
● All are parasitic

146
Q

Roundworms

A 
●	Cylindrical shaped body, tapered at end, unsegmented 
●	Intestinal
○	E.g. pinworm
●	Blood and Tissue 
○	E.g. Filarial worms and dog worm)
147
Q

Tapeworms

A

● Adult tapeworms live in the small intestine of humans
● Attach to intestinal wall by the scolex
○ Scolex consists of hooks and up to four suckers
● A tapeworm grows by the addition of body segments
○ Up to 3 - 5 meters long
○ Living up to 25 years
● Detected by the presence of ova (eggs) or proglottids (segments) in feces
○ Find segments wriggling and moving in stool

148
Q

Symptoms of tapeworm infection

A 
●	Diarrhea
●	Increased appetite
○	They are ingesting a lot but not gaining any weight
○	Calories are going to the worm
●	Intestinal obstruction
○	If they are sufficiently long
149
Q

Ex of tapeworm infection

A

E.g. Taenia solium
● Commonly known as the pork tapeworm
● Acquired by ingesting larva present in muscle tissue of a pig

150
Q

Enterobius vermicularis → pin worm

A

More common infection in children
● Child has pinworm infection
● It begins to grow
● Female forms of worm develop
● Worm crawls out of intestine to the anus
● Female worm lays eggs on the anus
● Makes child’s anus itchy
● They do not wash their hands → touch something → others can acquire it
● Ingestion of ova present on hands, fomites or linens
○ Eggs are able to survive bed sheets, hard surfaces and areas distal to intestine

151
Q

Pin Worm symptoms

A

● Nocturnal itching at the anus.

152
Q

Pin worm is detected by

A

● Wait til child is asleep, get them in froggy position, shine flashlight on anus
○ Parasite is attracted to the light
○ Female is most active in the evening
○ Attracts female worms
● Collecting ova or female worms from anal region using tape
● Worms visible in stool during the day
○ Easier in the evening
There is an oral antiparasitic medication that turns stool pink → EXPECTED

153
Q

Helminths → Reproduction

A

Life-cycles are highly complex

154
Q

Helminths → Reproduction Can include

A

Definitive host → sexual cycle takes place
Intermediate host → asexual cycle takes place
Paratenic host → no change in stage or development

155
Q

t/f: Helminths → Reproduction specific to each pathogen

A

true

156
Q

Plasmodium falciparum:

A

○ Anopheles mosquito is the definitive host
■ Sexual cycle occurs
○ Humans are the intermediate host
■ Asexual cycle occurs

157
Q

Taenia solium

A

○ Humans are both the definitive and intermediate host

158
Q

Helminths → Reproduction Transmission to humans varies with species:

A

● Ingestion of larvae in raw undercooked pig, beef, fish
● Ingestion of helminth eggs (feces)
● Insect bites or direct penetration through skin
● Life cycle is key to understanding the infectious process, time course of disease and symptomatology

Microbiology (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions