Microbiology: A Focus on Bacteria, Fungi, and Viruses Flashcards
1
Q
What is the microbiome?
A
Microbes live on and within the human body
2
Q
What is mutualism?
A
Both species benefit
3
Q
What is commensalism?
A
One benefits, the other is not harmed
4
Q
What is parasitism?
A
One benefits, the other is harmed
5
Q
What does PCR do?
A
Tests for specific gene in a complex
6
Q
What is the first line of defense that pathogens need to get past?
A
Epithelium
7
Q
What is the incubation period?
A
The time it takes the pathogen to enter the body and show the first symptom
8
Q
What are the factors that influence the incubation period?
A
- Health of host
- Growth rate of pathogen
- Degree of exposure
9
Q
What are two adhesion mechanisms of pathogens?
A
Pili and fimbrae
10
Q
What is an acute infection?
A
- Symptoms develop quickly
- Clears quickly
- Host has immunity for reinfection
11
Q
What is a chronic infection?
A
- Symptoms develop slowly
- Can last months to years
12
Q
What is a latent/persistent infection?
A
Illness never goes away, becomes dormant in the body and can be awakened with low immunity
13
Q
What transmission is person to person?
A
Horizontal transmission
14
Q
What transmission is mother to baby?
A
Vertical transmission
15
Q
What transmission is from an animal or arthropod?
A
Vector transmission
16
Q
What is the degree of pathogenicity of a pathogen?
A
Virulence
17
Q
What factors determine virulence of a pathogen?
A
Ability to invade and multiply within the host
18
Q
What are factors within the host that can influence a pathogen’s virulence?
A
- Diet
- Hormones
- Hygiene
- Health
19
Q
What is a strict pathogen?
A
Always causes disease
20
Q
What is an opportunistic pathogen?
A
Already part of normal microbial flora, takes advantage of weakened immune system
21
Q
How do bacterial cells hold their genetic information?
A
- No nucleus
- Chromosomes form a nucleotide
22
Q
Are bacterial cells eukaryotic or prokaryotic?
A
Prokaryotic
23
Q
What is the spherical shape of a bacterial cell classified as?
A
Cocci
24
Q
What is a diplococcus?
A
Pair of cocci cells
25
What is a streptococcus?
Chain of cocci cells
26
What is a staphylococcus?
Pyramidal shape of cocci cells
27
What is a tetrad?
4 cocci cells
28
What is a sarina?
Cube of eight cocci
29
What is a rod shaped cell classified as?
Bacilli
30
What is a diplobacilli?
Two bacilli cells
31
What is a streptobacilli?
Chain of bacilli cells
32
What is a palisades?
Looks like dominos of bacilli cells together
33
What is the intermediate shape between coccus and bacillus called?
Coccobacilli
34
What is a vibrio?
Curved or comma-shaped rod
35
What is a spirillum?
Thick, rigid spiral
36
What is a spirochete?
Thin, flexible spiral
37
What is it called when a bacterial cell does not have any characteristic shape and can change their shape?
Pleomorphic
38
What does gram positive stain?
Purple, retains crystal violet from iodine
39
What does gram negative stain as?
Pink, does not retain crystal violent and appears transparent (counter stain is pink)
40
What type of cells have a large peptidoglycan wall?
Gram positive
41
What type of cells have a lipopolysaccharide layer?
Gram negative
42
What type of cells have an outer membrane?
Gram negative
43
What is the LPS layer made out of?
Lipids and carbohydrates
44
What is peptidoglycan made out of?
Sugar and amino acids
45
Can the LPS play a role in a pathogen's ability to cause disease?
Yes
46
Is gram positive or negative cells more resistant to antibiotics? Why?
- Gram negative
- Has impenetrable cell wall
47
Do gram negative or gram positive develop resistance to antibiotics more quickly?
Gram negative
48
Can all bacteria be reliably classified through gram staining?
No
49
What are acidophiles?
Acid loving, grow optimally around pH of 2
50
What are alkalophiles?
Base loving, grow well at pH values near 10
51
What aciduric?
Acid tolerant, can survive in acidic conditions but do not necessarily grow
52
What are psychrophiles?
Prokaryotes that grow very poorly at temperatures above 15 degrees C
53
What are thermophiles?
Thrive at 100 degrees C
54
What structure covers the outer layer of the cell wall and is composed of polysaccharides?
Capsule
55
What is a virulence factor that mediates attachment of bacterium to host tissues?
Capsule
56
What structure can inhibit phagocytosis by neutrophils and macrophages?
Capsule
57
What is one of the causative agents of dental caries?
Streptococcus mutans
58
How do Streptococcus mutans attach to the tooth surface?
Capsule
59
What is a slime layer?
Some bacteria have a loosely adherent colloidal material that they secrete, usually similar to the capsule
60
What are pili?
Long hair-like tubular microfibers
61
What are fimbriae?
Bristle-like short fibers
62
What do pili and fimbrae do?
- Attachment
- Transfer of DNA
- Mobility
63
Do gram positive or gram negative cells have pili and fimbrae?
Gram negative only
64
Where does the flagella extend from?
Interior cell body, not from the capsule
65
What is the function of the flagella?
Mobility
66
Do gram positive or gram negative cells have flagella?
Both
67
What is the initial phase characterized by cellular activity but no growth?
Lag phase
68
What happens to the cells in the lag phase?
Cells increase in size but there is no cellular division
69
What phase do cells divide by binary fission and the metabolic activity is high?
Exponential/log phase
70
What phase are antibiotics and disinfectants are most effective in?
Exponential/log phase
71
What is the stationary phase?
Bacterial cell growth reaches a plateau
72
What phase has the same number of cells dividing is the same number of cells dying?
Stationary phase
73
What happens to the number of cells in the death phase?
Number of living cells decrease exponentially
74
Do gram positive or gram negative cells have the ability to produce spores?
Gram positive
75
When are spores formed?
Under adverse environmental conditions
76
What is the function of spores?
Protect DNA against heat, radiation, and attack by most enzymes and chemicals
77
What type of bacteria require oxygen for basic survival, growth, and reproduction?
Aerobic bacteria
78
What bacteria don't require oxygen for growth?
Anaerobic bacteria
79
What is an obligatory anaerobe?
Bacteria can't survive and multiply in the presence of oxygen
80
What is a facultative anaerobe?
Bacteria can survive with or without oxygen but may use it for their growth if available
81
What is an aerotolerant anaerobe?
Bacteria can't use oxygen for their growth but are not harmed by it
82
In a test tube, where do obligate aerobes migrate towards?
Gather at the top of the test tube, can only grow at the surface
83
In a test tube, where do facultative anaerobes migrate towards?
Spread throughout, often with heavier growth at the top
84
In a test tube, where do obligate anaerobes migrate towards?
Gather at the bottom, can only grow here
85
In a test tube, where do aerotolerant anaerobes migrate towards?
Relatively low growth throughout the whole test tube
86
In a test tube, where do microaerophiles migrate towards?
Grow just below the surface
87
What does bacterial metabolism need?
Glucose
88
Does fermentation require oxygen?
No
89
What process starts with the conversion of glucose?
Glycolysis
90
What conditions does glycolysis occur under in regards to oxygen?
Occurs in aerobic and anaerobic conditions
91
What conditions does fermentation occur under in regard to oxygen?
Anaerobic only
92
What process concerts pyruvate to various end products such as ethanol and lactic acid?
Fermentation
93
Do gram positive or gram negative cells release endotoxins?
Gram negative
94
What are the two ways that bacteria cause disease?
- Release of exotoxins
- Bacteria inhibit phagocytosis of immune cells
95
What is the first way bacteria cause disease?
Release of exotoxins
96
Do gram positive or gram negative release exotoxins?
Both
97
What is cytolysis?
Bursting of host cells from osmotic pressure
98
How do exotoxins work?
Receptor binding proteins cause cell death or change in function
99
What do exotoxins release?
- Enzymes
- Gas
- Acids
- Toxins
100
What structures can an exotoxin be encoded on?
Plasmid or bacteriophage
101
How do bacterial cells communicate?
Quorum sensing
102
What type of horizontal gene transfer picks up free genetic information and brings it into the cell?
Transformation
103
What type of horizontal gene transfer uses a pili to transfer information between two cells?
Conjugation
104
What type of horizontal gene transfer uses a bacteriophage to share genetic information?
Transduction
105
What type of cell uses conjugation as their method of horizontal gene transfer?
Gram negative
106
What causes DNA to be stronger?
Plasma
107
What is the second step for bacteria to cause disease?
Inhibiting phagocytosis
108
How do bacteria inhibit phagocytosis?
Protein attaches to the antibody and stops it from being eaten
109
Do immunocompromised patients need more or less bacterial cells to become infected?
Less
110
Are fungi prokaryotic or eukaryotic?
Eukaryotic
111
Do fungi like basic or acidic environments?
Acidic
112
An imbalance in what type of bacteria in the microflora could create a more acidic environment, and therefore allow fungi to grow?
Gram positive
113
What immune cell directly response to fungal infections?
TH17
114
What is a toxin on the fungal cell wall that the immune system may recognize?
Zymosan
115
What immune cells are associated with malaria infections?
TH1 and TH2
116
What drug is made from fungi?
Penicillium
117
Are fungi strict or opportunistic pathogens?
Opportunistic
118
What are oblige intracellular "parasites"?
Viruses
119
What features do viruses lack to be considered "living"?
- Do not reproduce on their own
- Do not maintain metabolism to gain energy on their own
120
What type of virus is typically more virulent?
Non-enveloped virus
121
How do non-enveloped viruses attack a host?
Cause host cell lysis, most common exit mode from host cell
122
What type of viruses are more resistant to extreme pH, heat, dryness, and simple disinfectants?
Non-enveloped viruses
123
How do non-enveloped viruses spread?
Fomites, hand to hand, and by small droplets
124
What extra structure do enveloped viruses have?
Outer membrane that surrounds the capsid
125
What process do enveloped viruses avoid, and therefore causes them to be less virulent?
Cell lysing
126
What type of virus is more sensitive to the environment and is not expected to be found in the GI tract?
Enveloped viruses
127
How do enveloped viruses spread?
- Large droplets
- Secretions
- Organ transplant
- Blood transfusion
128
Where does replication for DNA viruses occur?
In the nucleus
129
Are DNA viruses single or double stranded?
Double usually
130
What has to happen before proteins are synthesized in DNA viruses?
Transcription
131
A few DNA viruses can replicate in the cytoplasm because they have this structure?
(this is the exception not the rule)
They carry polymerases
132
What are the steps that DNA viruses go through to create proteins?
- DNA
- RNA
- mRNA (transcription)
- Proteins
133
What are the steps that RNA viruses go through to create proteins?
- DNA
- mRNA
- Proteins
134
Are RNA viruses single or double stranded?
Single usually
135
Are DNA or RNA viruses faster and more virulent?
RNA viruses
136
Where does replication occur in RNA viruses?
Cytoplasm
137
What is a positive strand RNA virus?
RNA virus that serve as mRNA and can immediately translate into proteins
138
Is a positive or negative stand RNA viruses faster and more virulent?
Positive strand RNA virus
139
What is a negative strand RNA virus?
Viral RNA must first be transcribed into the mRNA that can be translated into proteins
140
What is a retrovirus?
Reverse normal transcription, goes from RNA to DNA
141
HIV is an example of what kind of virus? What does it target specifically?
- Retrovirus
- Targets Helper T cells
142
What type of virus is HPV an example of?
DNA virus
143
What type of virus is herpes 1 and 2 an example of?
DNA virus
144
What type of virus is Varicella an example of?
DNA virus
145
What type of virus is Hep C an example of?
RNA virus
146
What type of virus is Coronavirus an example of?
RNA virus
147
What are the 7 steps for virus replication?
- Attachment
- Penetration
- Uncoating
- Replication
- Assembly
- Maturation
- Release
148
What is the mnemonic to remember the 7 steps for virus replication?
A PURple Apple Might Redded
149
What happens in the attachment step of virus replication?
Binding of the virus to the host cell, mediated by specific receptor molecules in the plasma membrane
150
What does HIV bind to in the attachment step of virus replication?
CD4 receptors
151
What happens in the penetration step of virus replication?
Virus crosses the plasma membrane, requires energy from host cell
152
What are the two ways a virus can enter the cell through virus replication?
Endocytosis or phagocytosis
153
What happens in the unceasing step of virus replication?
Breakdown of the capsid, causes release of the virus genome into the cell
154
What happens in the replication step of virus replication?
Virus genome is copied
155
What happens in the assembly step of virus replication?
Newly synthesized components are collected and are assembled into an immature virus particle
156
What happens in the maturation step of virus replication?
Final changes within an immature vision that result in infectious virus particle
157
What structure often changes in the maturation step?
Structural capsid
158
What happens in the release step of virus replication?
Release of vision into extracellular environment where it can continue the cycle
159
What are three ways a virus can be released from a host cell?
- Budding
- Lysis
- Exocytosis
160
What cycle makes more virions?
Lytic cycle
161
What cycle releases more bacteriophages?
Lytic cycle
162
What is the period between the infection of the host cell and lysing called?
Latent period
163
What is the lysogenic cycle?
Viral DNA is incorporated into the host cell
164
What is the period where the host cell lives and does not show signs of infection?
Dormant period
165
What immune cells stick to the surface of pathogens, prevent them from attaching to host cells, and targets pathogens for destruction?
B cells
166
What immune cells help activate B cells?
Helper T cells
167
What immune cells directly kill pathogens and infected cells?
Cytotoxic T cells
168
Is it easier or harder to treat fungal infections? Why?
- Harder
- Our cells are similar to fungal cells
169
Are viruses harder or easier to treat? Why?
- Harder
- They are inside our cells
170
Are bacterial cells harder or easier to treat? Why?
- Easier
- We have many mechanisms to recognize them
171
In order, what are the most difficult pathogens to treat?
- Fungi
- Viral
- Bacterial
