Module 2 - Bacterial Morphology and Taxonomy Flashcards
1
Q
How big are most eukaryotic cells?
A
Bigger than 5 um
2
Q
How big are most bacterial cells?
A
0.5 - 5 um in length
3
Q
How big are most viruses?
A
Less than 0.5 um
4
Q
Rank the following in size order: viruses, eukaryotic cells, bactera
A
Viruses < bacteria < eukaryotic cells
5
Q
What size can the naked eye see up to?
A
Up to 100 um
6
Q
What is used to visualize bacterial cells?
A
The light microscope
7
Q
What is the smallest bacterium discovered?
A
Mycoplasma gallicepticum
8
Q
What is special about Mycoplasma gallicepticum?
A
It is the smallest bacterium discovered
9
Q
What is the largest bacterium discovered?
A
Thiomargarita namibiensis
10
Q
What is special about Thiomargarita namibiensis?
A
It is the largest bacterium discovered
11
Q
True or false: Mycoplasma gallicepticum have a cell wall
A
False: they do not have a cell wall
12
Q
How come most antibiotics don’t work on Mycoplasma gallicepticum?
A
Most antibiotics target cell wall synthesis, but M. gallicepticum does not have a cell wall
13
Q
True or false: Mycoplasma gallicepticum is parasidic
A
True: it can cause disease
14
Q
Where can Mycoplasma gallicepticum be found when infecting a host?
A
The genital, respiratory, or bladder track
15
Q
How large is Thiomargarita namibiensis?
A
100-300 um, with some as large as 750 um
16
Q
What was Thiomargarita namibiensis named after?
A
The continental shelf of Namibia (where they were discovered in ocean sediments)
17
Q
What does coccus mean?
A
Spherical
18
Q
What is a spherical bacteria called?
A
Coccus
19
Q
What dos bacillus mean?
A
Rod-shaped
20
Q
What is a rod-shaped bacteria called?
A
Bacillus
21
Q
What does vibrio mean?
A
Curved rods
22
Q
What is a curved bacteria called?
A
Vibrio
23
Q
What does spirilla mean?
A
Spiral
24
Q
What is a sprial bacteria called?
A
Spirilla
25
What does pleiomorphic mean?
Varied shapes
26
What is a varied-shaped bacteria called?
Pleiomorphic
27
What can you say about the size of pleiomorphic bacteria?
Tend to be smaller than other bacteria
28
True or false: bacteria can organize into "multicellular" organisms
True: this organization can be seen in some bacteria
29
What are hyphae?
Branching filaments of cells
30
What are mycelia?
Tufts of hyphae
31
What are trichomes?
Smooth, unbranched chains of cells
32
What is an example of a bacteria that organizes into mycelia?
Cyanobacteria
33
What is special about Cyanobacteria?
They form mycelia filaments
34
What is an example of a bacteria that organizes into trichomes?
Myxobacteria
35
What is special about Myxobacteria?
They form trichomes
36
How do cyanobacteria create mycelia filaments?
They adhere through a common cell wall
37
What do Myxobacteria do (where they live)?
Feed on inorganic substances in the soil
38
What can be said about the genome of Myxobacteria?
It is relatively large
39
What shape is E. coli?
Bacillus
40
What shape is Treponema pallidum?
Spirilla
41
True or false: bacteria have ribosomes
True
42
True or false: all bacteria have a cell wall
False: most, but not all, bacteria have a cell wall
43
Where is cytoplasm found?
Between the nuclear region and the plasma membrane of the cell
44
What is the appearance of cytoplasm?
Gel like
45
What is the composition of cytoplasm?
80% water, 20% proteins/lipids/carbs/inorganic ions
46
What do protein filaments do?
Lead to rod or spherical shaped bacteria
47
What do ribosomes do?
Produce proteins
48
What are ribosomes composed of?
rRNA and proteins
49
What is a plasmid?
DNA separate from the chromosomal genes, and can replicate independently
50
What is the appearance of a plasmid?
Small, circular double stranded DNA
51
What occupies a big portion of the bacterial cytoplasm?
The nucleoid region
52
What is the nucleoid region?
The area with chromosomal DNA and replication machinery
53
What is the structure of a typical bacterial chromosome?
A singular, circular DNA strand
54
How can chromosomes vary from the typical structure?
Some bacteria have linear chromosomes, and some have more than one chromosome
55
What is another name for inclusion bodies?
Elementary bodies
56
What are inclusion bodies?
Cytoplasmic aggregates of stable substances (usually proteins)
57
What happens at inclusion bodies?
They are a site for viral replication, and contains capsid proteins
58
What are some examples of inclusion bodies?
Polyhydroxybutyrate granules, and sulfur globules
59
What happens at polyhydroxybutyrate granules?
Carbon storage
60
Which part of the bacteria acts in carbon storage?
Polyhydroxybutyrate granules
61
What happens at sulfur globules?
Sulfur storage
62
Which part of the bacteria acts in sulfur storage?
Sulfur globules
63
What is another name for gas vesicles?
Gas vacuoles
64
What are gas vesicles composed of?
Proteins
65
What is the structure of a gas vesicle?
A hollow, cylindrical tube closed by conical end caps
66
What is the purpose of gas vesicles?
Regulate position in water in response to light or nutrients
67
Where are gas vesicles usually found?
In planktonic organisms
68
How come gas vesicles are usually found in planktonic organisms?
Buoyancy control is crucial for these organisms
69
What are carboxysomes?
Polyhedral protein shells with RuBisCo
70
What does RuBisCo stand for?
Ribulose bisphosphate carboxylase
71
What do carboxysomes do?
Function in carbon fixation and the calvin cycle
72
What are magnetotactic bacteria?
Gram-negative bacteria that build magnetosomes
73
What is the structure of a magnetosome?
A lipid membrane with magnetite crystals
74
What is the purpose of magnetosomes?
Direction finding
75
Where does the magnetosome lead to?
Microaerophilic (low O2) environments for growth
76
What is the cytoskeleton composed of?
Proteins
77
What does the cytoskeleton do?
Organize components of the cell
78
What are some examples of cytoskeletal proteins?
MreB, FtsZ, ParR, and ParM
79
What is MreB a homolog of?
Actin
80
What is the structure of MreB, and where is it found?
Helical bands next to the plasma membrane
81
What type of bacteria universally contain MreB?
Nonspherical bacteria
82
Which bacteria rarely contain MreB?
Cocci
83
What does FtsZ stand for?
Filamenting temperature-sensitive mutant Z
84
What does FtsZ do?
Aids in cell division of the bactera
85
What does MreB do?
Helps form the shape of nonspherical bacteria
86
What is the structure of FtsZ, and where is it found?
A ring near the septum (where the bacterium splits)
87
What is FtsZ a homolog of?
Tubulin
88
Which protein is a homolog of actin?
MreB
89
Which protein is a homolog of tubulin?
FtsZ
90
What do ParR and ParM aid in?
The segregation of plasmids
91
What is needed for plasmids to move to daughter cells after division?
A ParC DNA site, and the proteins ParR and ParM
92
What is the ParMRC system?
The combination of the ParC DNA site, and the proteins ParR and ParM
93
What does ParM do?
Directs plasmid movement
94
Which other protein is like ParM?
Actin
95
What does ParR do?
DNA binding adaptor protein (connects ParC to ParM)
96
How does ParM interact with ParR and ParC?
It finds the plasmid filaments and the ParR/ParC components, and pushes the plasmids to opposite poles
97
What binds to ParC?
ParR
98
What does ParR bind to?
ParC
99
What is ParC?
A DNA binding site for ParR
100
What do cytoplasmic protein filaments do?
Contribute to the structural integrity of the cell
101
True or false: all cells have a plasma mebrane
True: it is required to separate external from internal
102
What is the composition of the plasma membrane?
A phospholipid bilayer with embedded proteins
103
What are the two types of proteins associated with the plasma membrane?
Peripheral proteins and integral proteins
104
What do peripheral proteins do, and where are they found?
They do not enter the membrane, and are found attached to the phosphate heads or integral proteins
105
What do integral proteins do, and where are they found?
They function as transporters, channels, linkers, receptors, energy accumulators, and cell adhesion proteins. They are found embedded within the membrane
106
What component do some (but not all) bacterial plasma membranes contain?
Hopanoids
107
What is the structure of hopanoids?
Pentacyclic compounds that mimic hopane
108
What are hopanoids analogous to?
Cholesterol
109
What are the functions of hopanoids?
Influence mobility and rigidity of the cell membrane
110
What is the purpose of hopanoids?
Adjust the cell membrane to adapt to extreme environments
111
How does CO2 and O2 get through the plasma membrane?
Through simple diffusion
112
How does H2O get through the plasma membrane?
Through aquaporins
113
What is osmosis?
The diffusion of water from lower solute concentration to higher solute concentration
114
What are the consequences of osmosis?
The cell could shrink or swell
115
How does a bacterium control the consequences of osmosis?
Through the cell wall
116
What is facilitated diffusion?
Diffusion of a nutrient down its concentration gradient through a specific channel protein
117
True or false: facilitated diffusion requires energy
False: it does not require energy, since it is moving down the concentration gradient
118
What is active transport?
Movement of a nutrient up its concentration gradient
119
True or false: active transport requires energy
True: it requires energy, since it is moving up its concentration gradient
120
What types of nutrients are usually transported through active transport?
Amino acids, glucose, ions, etc.
121
What are the two types of active transport?
Primary active transport and secondary active transport
122
What is primary active transport?
Using ATP as the source of energy in active transport
123
What is secondary active transport?
Using an electrochemical gradient as the source of energy in active transport
124
What are the 2 primary active transporters mentioned in this lecture?
P-type ATPases, and ABC transporters
125
What transporters usually transports ions?
P-type ATPases
126
What do P-type ATPases usually transport?
Ions (sodium, potassium, calcium, proton, etc.)
127
What is the purpose of a P-type ATPase?
Maintain membrane potential
128
What is the net reaction of the sodium potassium pump?
One ATP is used to move 3 Na out, and 2 K in
129
What does ABC transporter stand for?
ATP binding cassette transporter
130
What are some examples of ABC transporters?
MDR, CFTR, etc.
131
What is the structure of an ABC transporter?
4 subunits (2 hydrophobic, 2 hydrophilic)
132
What do the hydrophobic subunits of the ABC transporter do?
Form the transmembrane channel
133
What do the hydrophilic subunits of the ABC transporter do?
ATP binding domain on cytosolic portion of the cell
134
What does the associated subunit of the ABC transporter do?
Binds to the solute with high affinity
135
How do ABC transporters work?
The binding of the associated subunit causes ATP subunits to hydrolyze ATP, leading to conformation change and movement across the membrane
136
What is another name for secondary active transport?
Coupled transport, or co-transport
137
How does secondary active transport work?
One chemical moves down its electrochemical gradient, while another chemical moves up its electrochemical gradient
138
What is a common ion used in secondary active transport?
Sodium
139
What are the two types of cotransporters?
Symporters and antiporters
140
What is a symporter?
The two substances move in the same direction
141
What is an antiporter?
The two substances move in the opposite direction
142
What is an example of an antiporter?
The sodium-calcium exchanger (NCX)
143
What is an example of a symporter?
The sodium-glucose transporter
144
What does NCX stand for?
Sodium-calcium exchanger
145
What is the net reaction of NCX?
3 sodium into the cell, 1 calcium out of the cell
146
How does the plasma membrane capture energy?
It contains components of the ETC to create a proton gradient across the membrane
147
What does PMF stand for?
Proton motive force
148
What is PMF used for?
Respiration, photosynthesis, and motion (flagella)
149
What do the sensory systems of the plasma membrane do?
Change gene expression to respond to the environment
150
What proteins are involved in the secretion pathway?
The Sec proteins
151
What does the SecB protein do?
Associates to newly synthesized polypeptides that need to be secreted from the cell
152
How does the SecB protein alter the polypeptide?
It prevents it from folding, and directs it to SecA
153
What does SecA do?
It associates with SecB and SecYEG to hydrolyze ATP and push the polypeptide out of the cell
154
What does SecYEG do?
Form a channel protein that can allow for the polypeptide do be secreted
155
Which Sec protein associates with the newly synthesized polypeptides?
SecB
156
Which Sec protein hydrolyzes ATP and pushes the polypeptide out of the cell?
SecA
157
Which Sec protein forms the channel?
SecYEG
158
What does the signal peptidase do?
Removes the signal peptide from the polypeptide
159
Where is the signal peptidase found?
In the periplasmic space
160
What happens after the signal peptide is cleaved from the polypeptide?
It can fold into its conformational (protein) shape
161
What percentage of bacteria have a cell wall?
90%
162
What is the purpose of the cell wall?
Provide structure, strength, and protection from mechanical/osmotic forces
163
What is the cell wall of plants made out of?
Cellulose
164
What is the cell wall of fungi made out of?
Chitin
165
What is the cell wall of bacteria made out of?
Peptidoglycans
166
What is the structure of the cell wall?
Peptidoglycan layers crosslinked together (similar to a chain-link fence)
167
What is another name for the peptidoglycan?
Murein
168
True or false: peptidoglycans play a role in binary fission
True: they are important in reproduction
169
What is the structure of a peptidoglycan?
Disaccharide composed of NAG and NAM, and a small peptide chain
170
What type of molecules are NAG and NAM?
Amino sugars
171
What does NAG stand for?
N-acetylglucosamine
172
What does NAM stand for?
N-acetylmuramic acid
173
What holds together NAG and NAM?
Beta 1-4 glycosidic bond (alternate)
174
Where is the peptide chain found in the peptidoglycan layers?
Only on the NAM subunits
175
True or false: only one end of the peptide chain is attached to NAM
False: both ends of the peptide chain are attached only to NAM
176
True or false: the peptide chains on NAM are conserved within bacteria
False: they vary from species to species
177
What forms the 3D mesh-like layer of the peptidoglycan layer?
Crosslinking between the peptide chains
178
What is used to crosslink the peptide chains?
D amino acids
179
True or false: the crosslinking peptides between NAM are conserved within bacteria
False: they vary from species to species
180
Where is the cell wall formed?
Outside of the plasma membrane
181
What is the function of bactoprenol?
Move the peptidoglycans across the cell membrane
182
What is the structure of bactoprenol?
An amphipathic lipid that spans the entire membrane
183
What are the precursors of NAM and NAG?
Glutamine and fructose-6-phosphate
184
What happens after NAM and NAG are formed in the cytoplasm?
NAG reacts with UTP to made UDP-NAG
185
What does UTP stand for?
Uridine triphosphate
186
What does UDP stand for?
Uridine diphosphate
187
What happens after UDP-NAG is produced?
It is converted into UDP-NAM-NAG
188
What happens after UDP-NAM-NAG is produced?
The small peptide chain is added
189
What is stage 1 of cell wall formation?
Forming the subunit peptidoglycans
190
What is stage 2 of cell wall formation?
Transporting the subunits across the cell membrane
191
How does bactoprenol interact with the subunits?
It joins through a pyrophosphate bond, thus linking the peptidoglycan sugars with bactoprenol
192
What happens once the NAG-NAM is linked to bactoprenol?
It flips to bring the subunits to the periplasm
193
What type of molecule is bactoprenol-NAM-NAG?
A lipid
194
What happens once the bactoprenol-NAM-NAG is at the periplasm?
The NAM-NAG is added to the growing peptidoglycan chain
195
What happens in the transglycosylation reaction?
It displaces the bactoprenol lipid from the NAM-NAG sugars, by linking the hydroxyl group of NAG to the NAM in the growing chain
196
What is the chemistry of the transglycosylation reaction?
The hydroxyl group of NAG links to NAM in the growing chain, displacing it from bactoprenol
197
What enzyme catalyzes the transglycosylation reaction?
Transglycosylase
198
What enzymes can degrade the cell wall?
Lysozyme and lysostaphin
199
What does lysozyme do?
It breaks beta-1,4-glycosidic bonds between peptidoglycans
200
True or false: lysozymes can work on all bacteria
True: it can work on many bacteria
201
How come lysozymes can work on many bacterial cell walls?
Beta-1,4-glycosidic bonds are found in many bacteria
202
What does lysostaphin do?
Breaks the crosslinking bridges composed of glycine between peptides
203
True or false: lysostaphin can work on all bacteria
False: it can only work on certain Staphylococcus species
204
How come lysostaphin can only work on certain Staphylococcus species?
The peptide crosslinking various between bacterial species
205
What are examples of Staphylococcus species?
MSSA and MRSA
206
What happens if bacteria do not have an intact cell wall?
Bacteria lose their shape, especially bacillus
207
What is a protoplast?
The spherical shape a Gram-positive bacillus bacteria makes when it has no cell wall
208
What is a spheroplast?
The spherical shape a Gram-negative bacillus bacteria makes when it has no cell wall
209
What is the danger of a protoplast?
They can be easily lysed in hypotonic conditions
210
What are beta-lactam antibiotics?
Antibiotics that contain a beta-lactam ring
211
What do beta-lactam antibiotics do?
They prevent the crosslinking of peptidoglycan layers, thus weakening the cell wall
212
What are some examples of beta-lactam antibiotics?
Penicillin, cephalosporin, carbapenem, amoxicillin, and monobactam
213
What does beta-lactamase do?
Breaks the beta-lactam ring in beta-lactam antibiotics
214
What is another name for beta-lactamase?
Penicillinase
215
What is the significance of beta-lactamase?
The antibiotic cannot inhibit the crosslinking, and thus the cell wall stays intact, and the bacterium survives
216
How can scientists overcome beta-lactamase?
Use a combination of a beta-lactam antibiotic, and a molecule that can inhibit beta-lactamase
217
What is an example of a combination drug designed to overcome beta-lactamase?
Augmentin
218
What is an example of a competitive inhibitor of beta-lactamase?
Clavulanic acid
219
How can bacteria be distinguished based on the cell wall?
Gram-positive and Gram-negative
220
What is the origin of the name Gram-positive and Gram-negative?
The reaction to the procedure developed by Christian Gram
221
What is the Gram-stain procedure?
1. Cells are stained with crystal violet and iodine
2. Cells are washed with an organic solvent
3. Cells are stained with safranin
222
What is the purpose of the crystal violet dye in the Gram-staining technique?
It stains peptidoglycan purple
223
What is the purpose of the organic solvent in the Gram-staining technique?
It washes the crystal violet from certain bacteria
224
What is the purpose of the safranin in the Gram-staining technique?
It stains certain bacteria pink if they do not have crystal violet
225
What are the outcomes of the Gram-staining technique?
The bacteria will either look purple or pink
226
What does purple bacteria signify in the Gram-staining procedure?
Gram-positive bacteria
227
What does pink bacteria signify in the Gram-staining procedure?
Gram-negative bacteria
228
What leads to the different outcomes of the Gram-staining procedure?
Differences in the bacterial cell wall
229
What is the structure of a Gram-positive cell wall?
A thick layer of peptidoglycan (20-80 nm)
230
How thick is the peptidoglycan layer of Gram-positive bacteria?
20-80 nm
231
How much of the dry weight of Gram-positive bacteria is peptidoglycan?
90%
232
How large is the periplasmic space of Gram-positive bacteria?
Very narrow
233
What is the periplasmic space?
The space between the cell wall and the cell membrane in bacteria
234
Besides peptidoglycans, what are found in the cell wall of Gram-positive bacteria?
Teichoic acids
235
Where are teichoic acids found?
In Gram-positive bacteria
236
What is the structure of teichoic acids?
Negatively charged glycopolymers
237
Where are lipoteichoic acids found in the cell wall?
Linked to the membrane through glycolipids
238
Where are wall teichoic acids found in the cell wall?
Covalently linked to peptidoglycan
239
What is the function of teichoic acids?
Provide rigidity to the cell wall by attracting cations (sodium, magnesium, etc.)
240
What is the structure of a Gram-negative cell wall?
A thin layer of peptidoglycan, surrounded by another lipid membrane
241
What composes the outer membrane of Gram-negative bacteria?
Lipopolysaccharides and lipoproteins
242
How thick is the peptidoglycan layer of Gram-negative bacteria?
7-8 nm
243
How large is the periplasmic space in Gram-negative bacteria?
Larger than Gram-positive, but can still vary
244
How much of the dry weight of a Gram-negative bacteria is peptidoglycan?
10%
245
What is the structure of the outer membrane of Gram-negative bacteria?
A layer of phospholipids, and a layer of lipopolysaccharides
246
What does LPS stand for?
Lipopolysaccharides
247
What are the components of LPS?
Lipid A, core polysaccharide, and O side chain
248
What does O side chain stand for?
Outer side chain
249
What is the innermost region of LPS?
Lipid A
250
What is another name for Lipid A?
Endotoxin molecule
251
Wat does Lipid A do?
Anchors LPS to the outer membrane
252
How does Lipid A interact with humans?
It produces a strong inflammatory response
253
How can the O side chain interact with humans?
It can be changed by the microbe to evade host immunities
254
How do nutrients get through Gram-positive cell walls?
There are large pores in the peptidoglycan matrix
255
How do nutrients get through Gram-negative cell walls?
Through the porin and TonB proteins
256
What do the porin and TonB proteins do?
Allow nutrients to get through the Gram-negative cell wall
257
What does S-layer stand for?
Surface layer
258
Where is the S-layer (generally)?
Part of the cell envelope
259
How many organisms have an S-layer?
Many bacteria, and almost all archaea
260
What is the structure of the S-layer?
A monolayer of identical proteins or glycoproteins
261
What is the function of the S-layer?
Diverse: it varies from species to species (usually protection)
262
How is the S-layer attached in Gram-positive bacteria?
Attaches to peptidoglycan matrix through secondary cell wall polymers
263
How is the S-layer attached in Gram-negative bacteria?
It is closely associated with LPS of the outer membrane
264
What is one example function of the S-layer?
It may protect bacteria from bacteriophages or the immune system
265
What are bacteriophages?
Viruses that infect bacteria
266
What is a flagellum?
A lash or hair like appendage that protrudes from the cell body
267
How large is a flagellum?
15-20 nm in diameter
268
What is the primary function of the flagellum?
Motility or locomotion
269
What are the secondary functions of flagella?
Sensory organelle (sensitive to chemicals and temperature)
270
What defines flagella?
Function, not structure
271
What are polar flagella?
Flagella only at the ends of bacteria
272
What are monotrichous bacteria?
Bacteria with one flagellum at one end
273
If a bacterium has one flagellum at one end, what is it called?
Monotrichous
274
What are amphitrichous bacteria?
Bacteria with one flagellum at either end
275
If a bacterium has one flagellum at either end, what is it called?
Amphitrichous
276
What are lophotrichous bacteria?
Bacteria with multiple flagella at one end
277
If a bacterium has multiple flagella at one end, what is it called?
Lophotrichous
278
What are peritrichous bacteria?
Bacteria with multiple flagella all around the cell
279
If a bacterium has multiple flagella all around the cell, what is it called?
Peritrichous
280
What are axial filaments?
Flagella anchored at the periplasmic space (as opposed to the cell surface)
281
What species have axial filaments?
Some spirochetes
282
What is special about spirochetes?
They have axial filaments
283
What happens when axial filaments spin?
The whole cell spins like a corkscrew
284
Where does the energy to spin flagella come from?
The PMF
285
In bacteria, where is the proton pump machinery located?
On the plasma membrane
286
When happens when the flagella spin in one direction?
The bacterium moves in a straight line, and the flagella bunch together
287
What can you say about a bacterium moving in a straight line?
The flagella are spinning in one direction, bunched together
288
When happens when the flagella change their direction?
The bacterium tumbles, and the flagella come apart
289
What can you say about a bacterium that is tumbling?
The flagella are changing direction, spread apart
290
What are the three basic components of flagella?
A flagellar filament, hook, and basal body
291
What is the composition of the flagellar filament?
Flagellin protein
292
What does flagellin do?
Makes up the flagellar filament
293
How long is a normal flagellar filament?
5-10 um
294
Which is usually longer: the flagellar filament, or the cell?
The flagellar filament
295
What does the basal body do?
Anchors the flagellar filament to the cell envelope, and provides torque to the filament by interfacing with the motor
296
What is the structure of the basal body?
A disk-like structure
297
Where is the flagellar motor?
In the plasma membrane
298
What does the flagellar motor do?
Converts energy from PMF to drive rotation of the filament
299
What does the hook do?
Connects the filament to the basal body
300
What shape is the hook?
Curved
301
What interfaces with the flagellar motor?
The basal body
302
What is a pilus?
A hair-like appendage on the surface of many bacteria
303
What is the difference between pili and fimbriae?
Fimbriae are used for adhesion, while pili are used for conjugation
304
What is a sex pilus?
A pilus used for conjugation of plasmids
305
What is the composition of pili?
Pillin proteins
306
What does pillin do?
Subunit of pili
307
What is conjugation?
One bacterium donating one strand of its plasmid to another bacterium
308
What is another name for fimbriae?
Attachment pili
309
How do fimbriae compare to flagella?
Fimbriae are shorter and thinner than flagella
310
How come fimbriae are important for pathogenic bacteria?
Binding to the host target is an important first step in pathogenesis
311
What is another name for capsule?
K antigen
312
What are capsules composed of?
Polysaccharides
313
What type of bacteria have capsules?
Both Gram-positive and Gram-negative bacteria can have capsules
314
In what diseases is the capsule considered a major virulence factor?
Pneumonia and meningitis
315
What is the purpose of capsules?
Prevent bacteria from drying out, escape phagocytic action of host cells, and help form biofilms
316
What is the importance of biofilms?
Provide protection and enhanced survivability in harsh environments
317
True or false: all bacteria can be cultured
False: not all bacteria can be cultured
318
What is the order of taxonomy?
Domain --> kingdom --> phylum --> class --> order --> family --> genus --> species
319
What is a pneumonic for taxonomy?
King Philip Came Over For Good Spaghetti
320
What level is lower than species in taxonomy?
Strains
321
How is a bacteria named?
Through its genus and species
322
What is a genus?
A group of closely related species
323
What is a species?
A group of strains sharing common features, while differing considerable from other strains
324
What determines the shape of a bacterial cell?
The organization of the cell wall
325
In trichomes and mycelia, what are found in the partitions between cells?
Channels for intracellular passage of materials
326
What is needed to visualize viruses?
Electron microscopes
327
How do cations allow for DNA packing?
They positive charges can associated with negative DNA to pack it closer
328
What does topoisomerase do?
It is an enzyme that encourages the chromosome to coil upon itself
329
What is the purpose of topoisomerases?
Create supercoiling to pack the DNA
330
What does PHB stand for?
Polyhydroxybutyrate
331
What do PHBs do?
Act as a carbon storage
332
How can PHBs be used industrially?
They can be used as substitutes for plastics
333
What is the anammoxosome?
A compartment where ammonium is oxidized for energy
334
What does the Z-ring do?
It is formed by FtsZ proteins, and it aids in bacterial cell division. It also directs synthesis of the bacterial cell wall
335
How does the Z-ring constrict?
Through controlled release of FtsZ monomers through GTP hydrolysis
336
How does MreB work?
It guides the synthesis and formation of the cell wall into an elongated cylinder
337
What is the cell envelope?
The collection of the plasma membrane, cell wall, and outer membrane
338
What do cytochromes do?
Form the ETC
339
What is the sequence of the signal peptide?
A short sequence of large hydrophobic amino acids at the amino-terminal end of a polypeptide
340
How do mycoplasmas survive without a cell wall?
They live inside eukaryotic hosts
341
True or false: the cell wall is a permeability barrier
False: there is no selection to get through the cell wall
342
What is usually the first amino acid in the peptide on NAM?
L-Alanine (L-Ala)
343
What is usually the fourth and fifth amino acids in the peptide on NAM?
D-Alanine (D-Ala)
344
What happens to the fifth amino acid in the peptide on NAM?
It is removed when crosslinking occurs
345
In Gram-positive bacteria, what is usually the second amino acid in the peptide on NAM?
D-isoglutamine (D-GluNH2)
346
In Gram-negative bacteria, what is usually the second amino acid in the peptide on NAM?
D-isoglutamate (D-Glu)
347
What is usually the third amino acid in the peptide on NAM?
It varies greatly between species
348
What does transpeptidase do?
Crosslinks a pentapeptide precursor to the growing cell wall
349
What does the beta-lactam ring mimic?
D-Ala
350
True or false: beta-lactam antibiotics can target all cell walls
False: only cell walls that are currently growing can be affected by beta-lactam antibiotics
351
What is the composition of teichoic acids?
Ribitol phosphate or glycerol phosphate
352
What is the purpose of endospore formation?
It acts as a survival mechanism under stressful conditions
353
What are the characteristics of endospores?
Inert, and increased resistance to desiccation, UV light exposure, and high temperature
354
What is the composition of an endospore?
Additional layers of proteins outside of the peptidoglycan
355
What type of bacteria can create endospores?
Gram-positive bacteria
356
What is the purpose of oligosaccharides in the periplasm?
Help bacteria adjust to changes in osmolarity
357
What attaches the outer membrane to the cell wall?
Murein lipoprotein and peptidoglycan-associated lipoprotein
358
How does murein lipoprotein attach the outer membrane to the cell wall?
Links to the cell wall through carboxyl-terminal amino acid (lysine), and links to lipid chain through amino-terminal amino acid (cysteine)
359
What is the structure of porin?
Trimeric pores
360
What is the size limit of porins?
600 Da
361
How does TonB differ from porins?
TonB is better for scare nutrients
362
What proteins are found in complex with TonB?
ExbB and ExbD
363
Where does TonB get energy for active transport?
The proton motive force
364
What are autotransporters?
Proteins that can catalyze their own transit across the plasma membrane
365
What is the type III secretion pathway?
A "syringe" structure to cross the inner and outer membrane in one step
366
What is the type III secretion pathway related to?
Bacterial flagella
367
Which types of bacteria have the type III secretion pathway?
Gram-negative bacteria
368
How does the alcohol solvent interact with Gram-positive bacteria?
It strengthens the peptidoglycan matrix
369
How does the alcohol solvent interact with the Gram-negative bacteria?
It dissolves the outer membrane
370
What is chemotaxis?
The process of using chemical signals from the environment to direct motility
371
What controls if the flagella will all rotate in the same direction?
The cytoplasmic control system
372
What are chemoreceptors?
Receptors that detect attractants and repellants
373
What is special about Proteus mirabilis?
It can adapt to contact with surfaces by becoming hyper-flagellated
374
What is gliding motility?
Bacteria without flagella sliding smoothly over surfaces
375
What is twitching motility?
Relying on pili fibers to move along surfaces
376
True or false: all bacteria with pili can perform twitching motility
False: it is only inherent in certain pili bacteria
377
What is special about Shingella?
They move via the actin cytoskeleton within cells
378
What is a stalk?
A tubular extension of the entire cell envelope
379
What is the advantage of a stalk?
It increases the surface area to volume ratio, thus increasing nutrient uptake
380
What is a slime layer?
A less defined outer layer
381
What does glycocalyx refer to?
Both capsules and slime layers
382
How can an S-layer be lost?
If a cell does not need it anymore (such as in lab culture)
383
What is needed for each new taxon?
At least two different cultures of the bacteria in two different countries
384
What type of bacteria are part of Proteobacteria?
A wide range of Gram-negative bacteria, including human pathogens, nitrogen fixing bacteria, and photosynthetic bacteria
385
What is an example of a bacteria from Proteobacteria?
E. coli
386
Which phylum is mitochondria most closely related to?
Proteobacteria
387
What type of bacteria are part of Firmicutes?
A wide range of Gram-positive bacteria that have low GC content
388
What type of bacteria are part of Actinobacteria?
Gram-positive bacteria with high GC content
389
What are geosmins?
Organic compounds that have an aroma
390
What phylum produces geosmins?
Actinobacteria
391
What type of bacteria are part of Bacteroidetes?
Gram-negative bacteria that usually aid in digestion
392
What type of bacteria are part of Cyanobacteria?
Photosynthetic organisms
393
What are some bacterial phyla?
Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes, and Cyanobacteria
