Midterm #1 (lectures 2-11) Flashcards
1
Q
What are the 5 reasons that microbiology is important?
A
- Terraform the planet by producing oxygen
- Backbone of the food chain
- Cause disease
- Promote health
- Biotechnology and industries
2
Q
Was microbiology a thing before the microscope?
A
Yes
3
Q
What are some examples of historical microbiology?
A
Traditional medicines
Infrastructures
Fermented food/beverages
Acquired immunity
4
Q
What was the Miasma theory?
A
That infectious diseases were caused by bad air (miasma) emitted by rotting organic matter
5
Q
What was the theory of spontaneous generation?
A
Living organisms arise from non-living matter
6
Q
Who were the first to observe microbes?
A
Robert Hooke and Antonie van Leeuwenhoek
7
Q
What were the initial observations of Robert Hooke?
A
Described the fruiting structures of moulds, and the first descriptions of microorganisms
8
Q
What were the initial observations of Antonie van Leeuwenhoek?
A
The simple microscope, and observed/described bacteria
9
Q
What were the major contributions of Louis Pasteur?
A
Fermentation: specific microbes/spoilage = unwanted microbes
Pasteurization: kills bad microbes
Vaccinations
10
Q
What were the major contributions of Robert Koch?
A
Disproved the Miasma theory
Established link between disease and microbes
Laboratory techniques
11
Q
What were the major contributions of Sergei Winogradski?
A
Microcosm and Crossfeeding
The Winogradski columns
12
Q
What was the major contribution of Martinus Beijerinck?
A
Identified nitrogen fixing
13
Q
What are considered cellular microbes?
A
Prokaryotes (bacteria and archaea) and Eukaryotes (protists, fungi, micro-animals)
14
Q
What are considered acellular microbes?
A
Viruses and prion
15
Q
Why are viruses not considered in the Tree of Life?
A
They lack ribosomal RNA and do not have independent metabolism
16
Q
What are the three distinct domains in the Tree of Life?
A
Bacteria, Archaea, and Eukarya
17
Q
Why is there a move towards a two domain Tree of Life?
A
Used to think that archaea was ancient bacteria, but we are now moving towards the idea that archaea are ancient eukarya because the two are so distinct, but there are more similarities between archaea and eukarya than bacteria and archaea
18
Q
How do we classify and name cellular organisms? And is it bolded, italicized, or underlined?
A
Genus, Species. It is italicized
19
Q
What are the 3 different microscopy techniques?
A
Light, Electron, and Scanning Probe
20
Q
What are the two kinds of electron microscopy?
A
TEM and SEM
21
Q
Compare TEM to SEM
A
TEM: X-section of thinly sliced sample – great resolution
SEM: 3D-like images of surfaces
22
Q
What are the 5 kinds of light microscopy?
A
Brightfield, Darkfield, Phase Contrast, DIC, Fluorescent
23
Q
Compare brightfield to darkfield
A
Brightfield: use light
Darkfield: improve resolution of living samples + motility
24
Q
Compare DIC and Phase Contrast
A
DIC: generates 3D images of living samples
Phase Contrast: improve resolution of living samples + specific internal structures
25
Describe Fluorescent microscopy
Use fluorochromes to visualize sample
26
Explain the key points of cell theory
Living = made of cells that arise from another cell
Energy production
27
What is the key point of endosymbiotic theory?
The idea that mitochondria and chloroplasts are ancient bacteria
28
What was the development of the germ theory?
The new idea that infectious diseases are caused by germs not bad air from observation to Koch postulates.
29
What is the name of the round cell shape?
Coccus
30
What is the name of the rod cell shape?
Bacillus
31
What is the name of the curved rod cell shape?
Vibrio
32
What is the name of the short rod cell shape?
Coccobacillus
33
What is the name of the spiral cell shape?
Spirillum
34
What is the name of the long, loose helical spiral cell shape?
Spirochete
35
What is the name of a single coccus cell arrangement?
Coccus
36
What is the name of a pair of two cocci cell arrangement?
Diplococcus
37
What is the name of a grouping of four cells in a square cell arrangement?
Tetrad
38
What is the name of a chain of cocci cell arrangement?
Streptococcus
39
What is the name of a cluster of cocci cell arrangement?
Staphylococcus
40
What is the name of a single rod cell arrangement?
Bacillus
41
What is the name of a chain of rods cell arrangement?
Streptobacillus
42
Compare the size of bacteria to archaea to eukarya
Bacteria: 0.5 - 1μM
Archaea: 0.5 - 1μM
Eukarya: 5 - 20 μM
43
Compare the chromosome(s) location of bacteria to archaea to eukarya
Bacteria: nucleoid, no membrane
Archaea: nucleoid, no membrane
Eukarya: nucleus with a membrane
44
Compare the presence of organelles of bacteria to archaea to eukarya
Bacteria: no, inclusion or compartments
Archaea: no, inclusion or compartments
Eukarya: yes (ancestral bacteria)
45
Compare the endomembrane system of bacteria to archaea to eukarya
Bacteria: no, processes in cytoplasm
Archaea: no, processes in cytoplasm
Eukarya: yes (ER, Golgi, lysosomes)
46
Compare the ribosomes of bacteria to archaea to eukarya
Bacteria: 70S
Archaea: 70S
Eukarya: 80S, 70S for mitochondria/chloroplasts
47
What is the function and characteristics of the cytoplasmic membrane?
It is a barrier, an anchor, and helps with energy
48
Describe passive transportation of substrate across membranes
It is energy independent, and can be put into two categories:
1. Diffusion: through the membrane
2. Facilitated diffusion via proteins and dependent on concentration gradient
49
What are some other forms of transportation of substrate across membranes?
Proton motif force, ATP, Substrate phosphorylation
50
What are the two ways that we can cross the outer membrane?
Classical porins and substrate-specific porins
51
Describe Classical porins
Passive diffusion but made easier. It is not a carrier, but a water-filled channel. There are substrate preferences that depend on the amino acid composition of the channel
52
Describe Substrate-specific porins
Facilitated diffusion, carrier proteins (uniport). There is substrate specificity
53
Define the function and characteristics of the different cell envelope layers (microbe dependent)
Cytoplasmic membrane: barrier
Cell wall: cell shape, rigidity, protection, prevents osmotic lysis
Mycolic acids/OM: protection
S-layer
Capsule
54
What are the two ways of transport that are energy independent?
Simple and facilitated diffusion
55
Describe simple diffusion and its limitations
Enter via a concentration gradient. The limitation to number of substance is due to size and charge of the molecule, and the semi-permeable membrane
56
Describe the relationship between the rate and the concentration gradient
Linear
57
Describe facilitated diffusion and its limitations
More efficient than simple diffusion, the limitation is due to size and charge of the molecule as well as properties of the channel
57
What are the four types of energy dependent transport?
Active, coupled active, ABC transporter, group translocation
57
True or False: passive diffusion is inefficient for bacteria?
True
58
Describe active transport
Against the concentration gradient, and is for larger molecules. The source of energy is ATP/other high-energy-phosphate compounds, the substrate gradient, and the protonmotive force
59
True or False: active transport does not follow the Michaelis-Menten equation?
False
60
Describe coupled active transport
The simultaneous transport of two substances across a biological membrane. It may be a symport (the same direction) or antiport (opposite directions)
61
Describe ABC transporters
ATP-Binding Casette transporter. Utilize the energy of ATP binding and hydrolysis to transport various substrates across cellular membrane
62
Describe group translocation
Where a molecule crossing the cell membrane not only gets transported but also gets transformed in itself
63
Describe the differences in the bacterial cell wall between Gram-positive vs Gram-negative vs Acid-fast
Postive: thick peptidoglycan cell wall which includes NAG, NAM, tetrapeptides, and pentapeptides. Has teichoic acids.
Negative: thin peptidoglycan cell wall which includes NAG, NAM, tetrapeptides, and direct links. Has porins, and lipopolysaccharides (LPS)
Acid-fast: contains mycolic acids which gives it a waxy coating. Has a thick peptidoglycan wall and teichoic acids, so is mistaken for gram-positive
64
What is LPS?
Is an endotoxin, it contains lipid A and Pyrogen which is fever inducing that leads to septic shock. It serves as a way of attachment, mechanical strength, immune evasion, and protection
65
What are the two ways you can cross the OM?
Classical porins and substrate-specific porins
66
Describe classical porins
Passive diffusion but made easier, it is not a carrier, but a water-filled channel. It may have substrate preferences dictated by the amino acid composition of the channel
67
Describe substrate-specific porins
Facilitated diffusion, and is a carrier protein (uniport). Alwasy has substrate specificity
68
How would you cross the OM if you needed energy?
Highly-ligand-specific membrane receptors
69
Describe highly-ligand-specific membrane receptors
High affinity for ligands -> low concentration, Binding energy-independent but internalization of large nutrients requires energy. Involves a transfer of energy from the cytoplasm
70
Why is acid fast bacteria often mistaken as gram-positive?
| In terms of the cell wall
Coated with wax, and mycolic acids sit on top of a thick peptidoglycan cell wall
71
Compare and contrast the S-layers of bacteria and archaea
It is the outermost layer of the cell envelope
Bacteria: very few have the S-layer, is for protection and adhesion
Archaea: nearly all have the S-layer, protects against osmotic lysis and helps with cell shape
72
Define and describe the capsule/slime layer
Both are a sticky polysaccharide coat and the outermost layer
Capsule: tight matrix, excludes small molecules, and strongly attached to the cell
Slime layer: easily deformed, and loosely attached to the cell
73
What kind of cell wall is in acid-fast vs. gram positive vs. gram negative
Acid-fast: thick, pentapeptide inter-bridge, teichoic and lipoteichoic acids
Gram-positive: thick, pentapeptide inter-bridge, teichoic and lipoteichoic acids
Gram-negative: thin, Braun's lipoprotein
74
Is LPS found in acid-fast vs. gram positive vs. gram negative?
Acid-fast: no
Gram-positive: no
Gram-negative: yes
75
Are mycolic acids found in acid-fast vs. gram positive vs. gram negative?
Acid-fast: yes
Gram-positive: no
Gram-negative: no
76
Is an S-layer found in acid-fast vs. gram positive vs. gram negative?
Acid-fast: no
Gram-positive: yes
Gram-negative: yes
77
Is a capsule found in acid-fast vs. gram positive vs. gram negative?
Acid-fast: no
Gram-positive: yes
Gram-negative: yes
78
What are the differences in the membrane in terms of linkage between bacteria, archaea, and eukarya?
Bacteria: ester-linked, strain chain, bilayer
Archaea: ether-linked, branched chain, bilayer or monolayer
Eukarya: ester-linked, straight chain, bilayer
79
What are the differences in the cell wall between bacteria, archaea, and eukarya?
Bacteria: peptidoglycan (NAG + NAM), none
Archaea: S-layer, pseudomurein (NAG + NAT)
Eukarya: none, cellulose, chitin
80
What are the differences in the OM between bacteria, archaea, and eukarya?
Bacteria: yes (gram-negative), no (gram-positive)
Archaea: none, none
Eukarya: none
81
True or False: flagellum and archaellum are very structurally different
True
82
Describe the differences between flagellum and archaellum
Flagellum: related to type 3 secretion, hollow, proton motor force, assembles from the tip
Archaellum: related to type 4 pili and type 2 secretion, smaller than flagella, not hollow, driven by ATP, assembles from the base
83
Describe Twitching vs. Gliding
Twitching: ATP dependent, type 3 pili - extend then pull
Gliding: proton motive force, continuous and smooth motion without external propulsion
84
What are taxis?
Sense and respond to gradients, have the ability to move towards or away (swimming), and have complex regulatory coordination and network
85
What are chemotaxis?
Surface proteins (chemoreceptors), relay sensory input to flagellum, and affect rotation of the flagellar motor
86
What are osmotaxis?
Ionic strength
87
What are hydrotaxis?
Hydrated environment/water
88
What are phototaxis?
Gradient of light intensity
89
What are scotophobotaxis?
Move away from the absence of light
90
What are aerotaxis?
Oxygen
91
What are magnetotaxis?
Magnetic field, and a guide for oxygen
92
What are the differences in motility for bacteria vs. archaea vs. eukarya?
Bacteria: swimming, twitching, gliding
Archaea: swimming, twitching
Eukarya: swimming, flagella/cilia
93
What are the differences in flagella for bacteria vs. archaea vs. eukarya?
Bacteria: rigid, protein filament assembled at the top, rotate + PMF, T3SS
Archaea: rigid, protein filament assembled at the base, rotate + ATP, T2SS
Eukarya: flexible, microtubules + cytoplasmic membrane, whip + ATP
94
Define metabolism
Sum of catabolism and anabolism
95
Identify the source of energy, reducing power, and carbon for photo auto trophs
Energy: light
E-donor: n/a
Carbon: CO2
96
Identify the source of energy, reducing power, and carbon for photo hetero trophs
Energy: light
E-donor: n/a
Carbon: organic chemical
97
Identify the source of energy, reducing power, and carbon for photo litho auto trophs
Energy: light
E-donor: inorganic
Carbon: CO2
98
Identify the source of energy, reducing power, and carbon for photo organo hetero trophs
Energy: Light/chem
E-donor: organic
Carbon: organic chemical
99
Identify the source of energy, reducing power, and carbon for chemo litho auto trophs
Energy: chemical
E-donor: inorganic
Carbon: CO2
100
Identify the source of energy, reducing power, and carbon for chemo litho hetero trophs
Energy: chemical
E-donor: inorganic
Carbon: organic chemical
101
Identify the source of energy, reducing power, and carbon for chemo organo auto trophs
Energy: chemical
E-donor: organic
Carbon: CO2
102
Identify the source of energy, reducing power, and carbon for chemo organo hetero trophs
Energy: chemical
E-donor: organic
Carbon: organic chemial
103
Compare and contrast fermentation, aerobic respiration, and anaerobic respiration in terms of electron donor vs. electron acceptor
Fermentation: donor = organic molecule, acceptor = organic molecule
Aerobic: donor = glucose, acceptor = oxygen
Anaerobic: acceptor = something else
104
Compare and contrast fermentation, aerobic respiration, and anaerobic respiration in terms of energy yield
Fermentation: 2 ATP
Aerobic: 38 ATP
Anaerobic: 5-36 ATP
105
What is homofermentation?
Produce 1 fermentation product
106
What is heterofermentation?
Produce 2 different fermentation products
107
Fermentation is not _____ respiration
anaerobic
108
How do bacteria fix carbon dioxide?
Via the Calvin cycle, which provide carboxysomes.
109
How to bacteria fix nitrogen?
Via nitrogen fixation, N2 becomes NH3
110
How do bacteria divide?
Binary fission, 1 cell becomes 2 cells
111
What are the 5 steps in the bacterial cell cycle?
1. Chromosome replication
2. Elongation
3. Segregation
4. Z-ring formation
5. Division
112
In biofilm formation, what are the 4 key steps?
1. Attachment
2. Growth
3. Maturation
4. Detachment
113
Is biofilm formation considered a target of antibiotics?
No
114
Describe Direct Count using microscopy?
Smear preparation on a microscope glass slide, staining the smear, and counting microbial cells using a microscope. Gives only an estimated actual number of microorganisms from a sample
115
Describe Direct Count using current, aka a Coulter Counter
The count is achieved by observing the changes in voltage detected as either a cell or electrolyte travels through the aperture
116
What would be an appropriate way to do a viable count from a liquid sample that is too concentrated to view individual colonies?
Serial dilution
117
Describe the process to determine the Most Probable Number
Replicate portions of the original sample are cultured to determine the presence or absence of microorganisms in each portion. The replicate portions may be obtained from a serial dilution series.
118
Describe the process in a Turbidimetric process
A series of tubes containing different concentrations of antibiotics in a liquid culture medium inoculated with the test microorganism. Reading data obtained after incubation provides a curve displaying the antibiotic concentration
119
What are the pros of using a Microscopic count?
Wet or dry sample, easy, great for ecology
120
What are the cons of using a Microscopic count?
Tedious, dead cells and viable cells, need a high density, motility creates bias
121
What are the pros of using a Plate count?
One colony = one cell, easy, viable cells, great for microbial ecology
122
What are the cons of using a Plate count?
Tedious, bias due to growth conditions, the MPN is a guesstimate
123
What are the pros of using the Turbidimetric process?
Quick and easy, limited processing
124
What are the cons of using the Turbidimetric process?
Clumps increase bias, dead and viable cells, can be meaningless without proper context, not an actual count
125
Growth of bacteria is ____
predictable
126
Order these phases into the proper order:
1. Stationary phase
2. Death/decline phase
3. Lag phase
4. Log phase
3, 4, 1, 2
127
Describe the lag phase in the growth of bacteria
No increase in the number of living bacterial cells
128
Describe the log phase in the growth of bacteria
Exponential increase in number of living bacterial cells
129
Describe the stationary phase in the growth of bacteria
Plateau in number of living bacterial cells; rate of cell division and death roughly equal
130
Describe the death/decline phase in the growth of bacteria
Exponential decrease in number of living bacterial cells
131
What is considered the generation time?
Time to double population
132
What is the formula for generation time (g) involving time of exponential growth (t) and the number of generations (n)?
g = t/n
133
What is the formula for generation time (g) involving time of exponential growth (t), number of a cells at a certain time point (Nt), and initial number of cells (N0)?
g = t/[3.3(log (Nt/N0))]
134
What is the formula for the number of generations (n) involving number of a cells at a certain time point (Nt), and initial number of cells (N0)?
n = [(log Nt - log N0)/log 2]
135
What is auxotroph?
Requires addition of specific macromolecules because it does not synthesize them
136
What is phototroph?
Self-sufficient i.e. generate their own macromolecules from basic elements
137
What are copiotrophs?
Grow in high levels of nutrient
138
What are oligotrophs?
Require low nutrient levels to grow (high levels prevent growth)
139
What is a Defined medium?
Know exactly what went in it
140
What is a complexed medium?
Composition unknown
141
What is a Minimal medium?
Meets the minimum requirements
142
What is a Selective Medium?
Restricts growth of undesirables, and favors growth of desirables
143
What is a Differential medium?
Distinguished between types
144
Why do we use agar instead of gelatin?
Because it is solid at 37°C, and is not broken down by most organisms
145
Why would we use liquid cultures in a lab?
Because it is a closed system, we can shake to add oxygen, and has large volumes/biomass
146
What is the difference between batch culture and continuous culture?
Batch: used to grow microorganisms under limited nutrient availability in a closed system
Continuous: used to grow microorganisms under optimum and continual supply of nutrients in an open system
147
In which kind of culture can we control the growth rate and yield?
Continuous
148
Biofilms are ____ communities?
attached
149
What is an obligate aerobe?
An obligate aerobe is an organism that requires oxygen to grow
150
What is an obligate anaerobe?
organisms that can grow and survive only in the absence of oxygen
151
What is a facultative anaerobe?
organism that is able to grow either with or without free oxygen
152
What is an aerotolerant anaerobe?
do not perform aerobic respiration, they can grow in the presence of oxygen
153
What is a microaerophile?
microorganisms that proliferate in lower levels of oxygen
154
What is the benefit of using a "candle jar?"
Chemical reaction to remove most but not all of the O2 in the chamber
155
Oxygen leads to ____ ______ _____ (ROS)
Reactive Oxygen Species
156
What is the reaction involved in superoxide dismutase?
Superoxide anions to peroxide
157
What is the reaction involved in peroxidase?
hydrogen peroxide to water and oxidized electron donor
158
What is the reaction involved in catalase?
hydrogen peroxide to water and oxygen
159
What is a psychrophile?
Cold loving
160
What is a mesophile?
neither hot nor cold, just right
161
What is a psychrotroph?
between psychrophile and mesophile
162
What is a thermophile?
love warmth
163
What is a hyperthermophile?
love it burning hot
164
What is an acidophile?
grows at pH 1-~5.5
165
What is a neutrophile?
grows at pH ~5.5 - ~8.5
166
What is a alkaliphile?
grows at pH ~7.5 - ~11.5
167
What is a non-halophile?
Salt concentration up to 0.3M (0.8%)
168
What is a halotolerant?
Salt concentration of 0.3-0.8M (1.7-4.8%)
169
What is a halophile?
Salt concentration of 0.8-3.4M (4.7-20%)
170
What is an extreme halophile?
Salt concentration of 3.4-5.1M (20-30%)
171
What is xerophilic?
high sugar
172
What are barophiles?
High atmospheric pressure
173
What is a virus?
A genetic element encapsulated in a protein shell (capsid)
174
Describe a virus
- DNA or RNA (but never both)
- Double stranded, single stranded
- Segmented (multiple fragments) or non-segmented (1 fragment)
- May be surrounded by a membrane
175
Why are viruses not considered living?
They do not carry independent metabolism
176
Because they need a host for energy and protein synthesis, viruses are considered _____ ______ ______
obligate intracellular parasites
177
True or False: viruses infect all cellular life forms?
True
178
The extracellular form of a virus is called a ..?
virion
179
What is a bacteriophage?
A virus that parasitizes a bacterium by infecting it and reproducing inside it
180
What is an archaeaphage?
Archaea are also infected by viruses, whether these should be referred to as 'phages' is debatable
181
What is a virophage?
Virophages are satellite viruses; that is, they are defective viruses that need a helper virus to provide missing functions
182
Viral structures are very small, and therefore not observable with a ____ _____
light microscope
183
Capsids have protein subunits called _____?
capsomeres
184
Capsids have 1 or more ____ proteins
different
185
In symmetry, there are two primary shapes: ?
1. Rod
2. Spherical
186
What kind of symmetry is a Rod?
helical
187
What kind of symmetry is spherical?
icosahedral
188
Length of a viral rod is dependent on ?
The length of nuclei acid strand
189
Width in a viral rod is dependent on ?
Size and packaging of capsomeres
190
Icosahedral symmetry is the ____ and ____ ____ arrangement
simplest, most effective
191
Between the rod and spherical symmetry, which of the two require the fewest capsomeres?
Spherical
192
Icosahedral head + helical tail is an example of what?
A complex shape
193
Compare a naked virion to an enveloped virion?
Naked: capsid + nucleic acid
Enveloped: membrane + capsid + nucleic acid
194
In virion, the phospholipid bilayer is derived from ? and what proteins does it contain?
The host, mostly animal viruses; host proteins + viral proteins
195
What are fibrils?
peptidoglycan-like polymer on amoeba viruses
196
If you block the spike, you block the ___?
attachment
197
What are spike proteins?
Proteins at the surface of viruses, they attach and enter host cells
198
Do virion only pack nucleic acids?
No, some viruses carry enzymes
199
What kind of enzyme do bacteriophages carry?
Lysozyme-like enzyme
200
What kind of enzyme do RNA viruses carry?
RNA replicase
201
What kind of enzymes do retroviruses carry?
Reverse transcriptase
202
In naming viruses, is both the species name and viral name in italics?
No, only the species name
203
When identifying viruses, what should you beware of?
Differentiating name from the disease it causes. HIV vs AIDS for example
204
What classification system do we use for viruses?
The Baltimore Classification
205
What is the 1st Baltimore Classification, and what steps does it involve?
BCI: double-stranded (ds) DNA viruses
+/-DNA → mRNA
206
What is the 2nd Baltimore Classification, and what steps does it involve?
BCII: single-stranded (ss) DNA viruses
+DNA → +/-DNA → mRNA
207
What is the 3rd Baltimore Classification, and what steps does it involve?
BCIII: dsRNA viruses
+/-RNA → mRNA
208
What is the 4th Baltimore Classification, and what steps does it involve?
BCIV: positive-sense (+) RNA viruses
+RNA → -RNA → mRNA
209
What is the 5th Baltimore Classification, and what steps does it involve?
BCV: negative-sense (-) RNA viruses
-RNA → mRNA
210
What is the 6th Baltimore Classification, and what steps does it involve?
BCVI: reverse-transcribing RNA viruses
+RNA → -DNA → +/-DNA → mRNA
211
What is the 7th Baltimore Classification, and what steps does it involve?
BCVII: reverse-transcribing dsDNA viruses
+/-DNA → +RNA → -DNA → +/-DNA → mRNA
212
To create mRNA, you need a _____ strand DNA
negative
213
To create a protein, you need a _____ strand RNA
positive
214
How viruses infect their hosts depend on..?
The host, their Baltimore classification, and their type (naked or enveloped)
215
Order these steps properly for "How do phages infect bacteria:"
1. Biosynthesis: phage DNA replicates and phage proteins are made
2. Attachment: the phage attaches to the surface of the host
3. Penetration: the viral DNA enters the host cell
4. Lysis: the cell lyses, releasing newly made phages
5. Maturation: new phage particles are assembled
2, 3, 1, 5, 4
216
Order these steps properly for a "one-step growth curve:"
1. Burst size: number of virions released per bacterium
2. Inoculation: inoculum of virus binds to cells
3. Burst: host cells release many viral particles
4. Eclipse: virions penetrate the cells
2, 4, 3, 1
217
Order these steps properly for "how do temperate phages infect bacteria:"
1. The phage DNA becomes incorporated into the host genome
2. The cell lyses, releasing the newly made phages
3. The phage infects a cell
4.New phage particles are assembled
5. Under stressful conditions, the prophage DNA is excised from the bacterial chromosome and enters the lytic cycle
6. The cell divides, and prophage DNA is passed on to daughter cells
7. Phage DNA replicates and phage proteins are made
3, 1, 6, 5, 7, 4, 2
218
Order these steps properly for "how do viruses infect eukaryotes:"
1. Assembly
2. Attachment: binding to the receptor(s): spike protein, host and tissue specificity
3. Biosynthesis: production of genome, mRNA, and proteins. Replication in the nucleus
4. Release
5. Uncoating: viral content is released
6. Penetration: engulfment: endocytosis/membrane fusion
2, 6, 5, 3, 1, 4
219
What are 3 outcomes of a viral infection?
1. Lytic
2. Persistent
3. Cancer
220
What is Lytic in terms of outcomes of a viral infection?
Cell lysis to release viral particle
221
What are the 2 subtypes of Persistent in terms of the outcome of a viral infection?
Latent: virus is dormant and reactivates
Chronic: virus is not eliminated, continuous production of viral particle
222
What are the two types of Cancer?
Direct: viral oncogenes, activation of oncogenes
Indirect: chronic infection
223
Order these steps properly for " how do viruses chronically infect eukaryotes:"
1. Penetration
2. Uncoating
3. Biosynthesis
4. Integration
5. Attachment
6. Release
7. Assembly
5, 1, 2, 4, 3, 7, 6
224
What are the 3 requirements in order to grow a virus?
1. Needs living host cells
2. Needs the host cell type to support a viral infection (permissive host, receptors, etc)
3. Know the conditions to grow the host
225
What is plaque?
Lysis of a host cell
226
1 plaque = 1 _____ ______
infectious virion
227
Lytic vs lysogenic infections
Lytic: the reproduction of viruses using a host cell to manufacture more viruses; the viruses then burst out of the cell.
Lysogenic: the incorporation of the viral genome into the host cell genome, infecting it from within
228
What are viroids?
Short strand of circular RNA capable of self-replication, they do not have a protein coat
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What are virusoids?
Non-self-replicating single stranded RNAs. They need specific "helper" viruses (i.e. co-infection). Belong to satellite RNAs
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What are prions?
Misfolded proteins that misfold normal proteins
