Lecture 2 (bacterial Cell structure with some Archaea stuff) Flashcards
(242 cards)
1
Q
Prokaryotes differ from eukaryotes in size and _____
A
simplicity
2
Q
most prokaryotes lack
A
internal membrane systems
3
Q
is the term prokaryotes becoming blurred
A
yes
4
Q
prokaryote comes form the Greek words for
A
pre-nucleus
5
Q
Eukaryote comes form the Greek words for
A
true nucleus
6
Q
Are most bacteria monomorphic
A
Yes
7
Q
What does monomorphic mean
A
one shape
8
Q
Are a few bacteria pleomorphic
A
yes
9
Q
what does pleomorphic mean
A
multiple shapes
10
Q
What are the three basic bacteria shapes
A
- Bacillus (rod-shaped)
- Coccus (spherical)
- Spiral
11
Q
what are the three types of spiral shapes
A
- Spirillum
- Vibrio
- Spirochete
12
Q
What is Spirillum
A
Spiral shaped with one or more twists
13
Q
What is Vibrio
A
type of Spiral shaped
-Curved rod
14
Q
What is Spirochete
A
- Type of Spiral shape
- Flexible, helical, spirals
15
Q
Diplo-
A
pairs
16
Q
Staphylo-
A
Clusters
17
Q
Strepto-
A
Chains
18
Q
The division in staphylo- is in _____ planes
A
multiple
19
Q
The division in Strepto- is in ____ planes
A
a single plane
20
Q
Organisms that are variable in shape
A
pleomorphic
21
Q
Network of long, multinucleate filaments
A
mycelium
22
Q
what is the smallest bacteria
A
Mycoplasma (0.3 micrometers)
23
Q
The average rode size
A
1.1-1.5 x 2-6 micrometers
size of E. coli
24
Q
Epulopiscium fishelsoni is a ___ (size) bacteria
A
very large - 600 x 80 micrometers
25
____ cells have a larger surface area to volume ratio
smaller cells
26
Function of plasma membrane in bacteria
- Selectively permeable barrier
- Mechanical boundary of cell
- Nutrient and waste transport
- location of many metabolic processes (respiration, photosynthesis)
- detection of environmental cues for chemotaxis
27
What is the function of the Gas Vacuole in bacteria
an inclusion that provides buoyancy for floating in aquatic environments
28
What is the function of the ribosomes in bacteria
Protein Synthesis
29
What is the function of inclusions in bacteria
storage of carbon, phosphate, and other substances
30
What is the function of nucleotide in bacteria
localization of genetic material (DNA)
31
What is the function of Periplasmic space in bacteria
- in typical Gram-negative bacteria, contains hydrolytic enzymes and binding proteins for nutrient porcessing and uptake
- In typical Gram-positive bacteria it may be smaller or absent
32
what is the function of the cell wall in bacteria
- protection form osmotic stress
| - helps maintain cell shape
33
What is the function of Capsules and slime layers in bacteria
- Resistance to phagocytosis
| - Adherence to surfaces
34
What is the function of Fimbriae and pili in bacteria
- Attachement to surfaces
- bacterial conjugation and transformation
- Twitching and gliding motility
35
What is the function of Flagella in bacteria
- Swimming and Swarming motility
36
What is the function of endospore in bacteria
Survival under harsh environmental conditions
37
What are the components of the bacterial cell envelope
- Plasma membrane
- Cell wall
- Layers outside the cell wall
38
do some bacteria have an internal membrane system
yes
39
is a plasma membrane an absolute requirement for all living organisms
yes
40
Bacterial membranes lack _______, which is present in Eukaryotic membranes but they do contain _____
sterols (like cholesterol), but do contain Hopanoids
41
What is the function of Hopanoids in the bacterial membranes
is a sterol-like molecule and stabilizes the membrane
42
are Hopanoids found in petroleum
yes
43
Lipid composition of bacterial membranes varies with
environmental conditions (ex. Temperature)
44
do many bacteria have plasma membrane infoldings
yes
45
some Archaeal membranes have a ____ structure instead of a bilayer structure
monolayer
46
Are Archaeal membranes composed of lipids that differ chemically from those of Bacteria and Eukaryotes
Yes
47
bacterial and eukaryotic lipids contain ___ bonds while Archaeal lipids contain ____ bonds
Ester, Ether
48
bacterial and Eukaryotic lipids have ___ hydrocarbons attached to glycerol
2
49
special features of Archaeal lipids
- Ether bonds
- Branched molecules
- Tetraethers (some) (note these make a monolayer)
50
what are the functions of the Plasma membrane
- Encompasses the cytoplasm
- Selectively permeable Barrier
- Interacts with External environment
- receptors for detection of and response to chemical surroundings
- Transport systems
- Metabolic processes
51
Substance in which nucleotide, ribosomes, inclusion bodies, plasmids, and cytoskeletal filaments are suspended
Cytoplasm of Bacteria and Archaea
52
The cytoplasm of bacteria and Archaea lack _____ and are composed largely of ___
- lack organelles bound by unit membranes
| - composed largely of water
53
Homologs of all 3 eukaryotic cytoskeletal elements have been identified in bacteria. What are they
- Actin
- Intermediate filaments
- Microtubules
54
Are the functions of the cytoskeleton in bacteria similar to in eukaryotes
yes
55
Function of microtubule homolog FtsZ in Bacteria
Cell division
56
Microtubule homolog FtsZ is widely observed in
bacteria and archaea
57
Function of microtubule homolog BtubA/BtubB in Bacteria
Unknown
58
microtubule homolog BtubA/BtubB is only observed in ____ and thought to be encoded by
Only observed in Prosthecobacter spp
| thought to be encoded by eukaryotic tubular genes obtained by horizontal gene transfer
59
Function of microtubule homolog TubZ in bacteria
Possibly plasmid segregation
60
Microtubule homolog TubZ is encoded by ____ and observed in
large plasmids and observed in members of the genus Bacillus
61
Function of actin homolog MamK in bacteria
Positioning magnetosomes
62
Function of actin homolog MreB/Mbl in bacteria
Helps determine cell shape
may be involved in chromosome segregation
localizes proteins
63
Function of actin homolog ParM in bacteria
Plasmid Segregation
64
Actin homolog MamK is observed in
magnetotactic species
65
Actin homolog MreB/Mbl is observed in
Most rod-shaped bacteria
66
Actin homolog ParM is ____ encoded
plasmid
67
function of intermediate filament homolog CreS (Crescentic)
Induces curvature in curved rods
68
Intermediate filament homolog CreS (crescentin) is observed by
Caulobacter crescentus
69
What are two unique bacterial cytoskeletal proteins
MinD and ParA
70
What is the function of the unique bacterial cytoskeletal protein MinD
prevents polymerization of FtsZ at cell poles
71
What is the function of the unique bacterial cytoskeletal protein ParA
Segregates chromosomes and plasmids
72
The unique bacterial cytoskeletal protein MinD is observed in
Many rod-shaped bacteria
73
The unique bacterial cytoskeletal protein ParA is observed in
many species including Vibrio cholerae, C. crescentus, and Thermus themophilus
74
Microtubule homolog FtsZ is observed in ____ and forms
many bacteria and forms ring during septum formation in cell division
75
Actin homolog MreB is found in ____ and not ___ and maintains
found in bacilli and not cocci
| maintains shape by positioning peptidoglycan synthesis machinery
76
Intermediate filament homolog CreS is rare, and maintains
curve shape
77
Inracytoplasmic membranes can be seen as plasma membrane infolding in
- many photosynthetic bacteria
| - many bacteria with high respiratory activity
78
what is Anammoxosome in Plantomycetes
- an Intracytoplasmic Membrane
| - An organelle that is the site of anaerobic ammonia oxidation
79
What are inclusions
granules of organic or inorganic material that are stockpiled by the cell for future use
80
what are some storage inclusions
- Storage of nutrients, metabolic end products, energy, building blocks
- Glycogen storage
- Carbon Storage
- Poly-beta-hydroxybutyrate (PHB)
- Glycogen
- Phosphate-Polyphosphate granules (Volutin)
- Amino Acids- cyanophycin granules
- Sulfur Granules
81
Sulphur granules are important in bacteria that don't use
water
82
Gas vacuoles are found in
aquatic, photosynthetic bacteria and archaea
83
Gas Vacuoles are Aggregates of hollow cylindrical structures called
gas vesicles
84
Function of Gas Vacuoles
Provide buoyancy in gas vesicles
85
Magnetosomes are found in ____ bacteria
aquatic
86
what are the function(s) of magnetosomes
magnetite particles (iron) for orientation in Earth's magnetic field
87
Cytoskeletal protein ____ helps form magnetosome chain
MamK
88
Microcompartments in bacteria are not bound by membranes but ________ for specific function
compartmentalized
89
What are carboxysomes
Microcompartments in CO2 fixing bacteria
| - contain the enzyme ribulose-1,5-Bisphosphate carboxylase (Rubisco), enzyme used for CO2 fixation
90
complex protein/RNA structures that are the sites of protein synthesis
Ribosomes
91
What is the size of bacterial and archaea ribosomes
70S
92
What is the size of Eukaryotic ribosomes
80S
93
What does the S in 80S ribosome stand for
Svedburg unit
94
What are the Bacterial ribosomal RNA subunits
- 16S small subunit
| - 23S and 5S in large subunit
95
The nucleoid of bacteria is usually not _____ bound
membrane bound (there are a few exceptions)
96
____ is the location of chromosome and associated proteins in Bacteria
Nucleoid
97
The nucleoid of bacteria usually 1
closed circular, double stranded DNA molecule
98
_____ and ______ (different from histones) aid in folding of DNA in bacteria
Supercoiling and nucleoid proteins
99
Characteristics of Prokaryotic Chromosome
- Usually a circular, double-stranded DNA molecule
- Usually only one
- Looped and coiled extensively
100
what are plasmids
- extrachromosomal DNA
- Found in bacteria, archaea, and some fungi
- usually small, closed circular DNA molecules
- Exist and replicate independently of chromosome
- Episomes- may integrate into chromosome
- inherited during cell division
- Contain few genes that are non-essential
- confer selective advantage to host (e.g., drug resistance)
- Classification based on mode of existence, spread, and function
101
Plasmids are found in
bacteria, archaea, and some fungi
102
plasmids exist and replicate _____ of the chromosome
independently
103
function of conjugative plasmids
Transfer of DNA form one cell to another
104
Example of conjugative plasmids
F factor
105
Phenotypic features of conjugative plasmids
- Sex pilus
| - Conjugation
106
Hosts for conjugative Plasmids
- E. coli
- Salmonella
- Citrobacter
107
What is the function of R plasmids
carry antibiotic-resistance genes
108
What is an example of R plasmids
RP4
109
What are the hosts of R plasmids
- Pseudomonas
| - many other gram-negative bacteria
110
What are the phenotypic features of R plasmids
- Sex pilus
- Conjugation
- resistance to Amp, Km, Nm, Tet
111
Function of Col plasmids
produce bacteriocins, substances that destroy closely related species
112
host(s) of Col plasmids
E. coli
113
Phenotypic features of Col Plasmids
Colicin E1 production
114
Function of Virulence Plasmids
Carry virulence genes
115
Example of Col Plasmids
ColE1
116
Example of virulence plasmids
Ti
117
Hosts of Virulence plasmids
-Agrobacterium tumefaciens
118
Phenotypic features of virulence plasmids
-Tumor induction in plants
119
Function of metabolic plasmids
-carry genes for enzymes
120
Example of metabolic plasmids
CAM
121
Hosts of metabolic plasmids
Pseudomonas
122
Phenotypic features of Metabolic Plasmids
Camphor degradation
123
Rigid structure that lies just outside the cell plasma membrane
Peptidoglycan (murein)
124
Stain purple, thick peptidoglycan
Gram-Positive Bacteria
125
Stain pink or red; thin peptidoglycan and outer membrane
Gram-Negative Bacteria
126
what are the functions of the cell wall
- Maintains shape of the bacterium
- almost all bacteria have one
- Helps protect cell from osmotic lysis
- Helps protect from toxic materials
- may contribute to pathogenicity
127
Peptidoglycan is a meshlike polymer of identical subunits forming long strands. Two alternating sugars ____ and ___ and alternating ___ and ____ amino acids
- Two alternating sugars
- N-acetylglucosamine (NAG)
- N-acetylmuramic acid
- 4 alternating D- and L- amino acids
128
Chains of peptidoglycan subunits are joined by _______ between the peptides
cross-links (covalent bonds)
129
What are the three amino acids found in peptidoglycan that are not found in proteins
- D-glutamic acid
- D-alanine
- meso-diaminopimelic acid
130
What is the importance of D-amino acids in peptidoglycan
protects against degradation by most peptidases, which recognize only the L-isomers of amino acid residues
131
What are the four amino acids that alternate in the structure of peptidoglycan
- L-Alanine
- D- Glutamic acid
- Meso-Diaminopimelic acid
- D- Alanine
132
The pentapeptide side chain of peptidoglycan terminates with
two D-alanines
133
Peptidoglycan strands have a ____ shape
helical
134
Peptidoglycan chains are cross linked by _____ for strength
peptides
135
bacteria can cross-link the strands by connecting the carboxyl group of the _____ at position 4 directly to the amino group of _______ (position 3) of the other strand ( the position 5 ______ is removed as the cross-link is formed)
D-Alanine, diamiopimelic acid, D-Alanine
136
A peptide interbridge is composed of ____ and goes from ___ of one strand to ___ on the other strand
5 glycines, D-alanine, L-lysine
137
Peptidoglycan sacs are _____ networks
interconnected
138
Peptidoglycan chains cross-linking is common in
Gram-negative bacteria
139
Gram positive cell walls are composed primarily of
peptidoglycan
140
Gram positive cell wall are primarily composed of peptidoglycan and may also contain _____
teichoic acid (which is negatively charged)
141
What is the function of teichoic acids in the cell walls of gram-positive cell walls
- Helps maintain cell envelope
- Protect from environmental substances
- may bind to host cells
142
Do some gram-positive bacteria have layer of proteins on surface of peptidoglycan
yes
143
The periplasmic space of Gram positive bacteria lies between ___ and ____ and is ___ than that of Gram-negative bacteria
plasma membrane and cell wall and is smaller than that of Gram negative bacteria
144
The periplasm of gram positive bacteria has relatively few _____
proteins
145
Enzymes secreted by Gram-positive bacteria are called
exoenzymes
146
Exoenzymes, which are secreted by gram-positive bacteria aid in
degradation of large nutrients
147
which has more complex cell walls gram-negative or gram-positive bacteria
Gram-negative
148
The cell wall of gram-negative bacteria consists of a ____ layer of peptidoglycan surrounded by an
thin layer of peptidoglycan surrounded by an outer membrane
149
The outer membrane of gram-negative cell walls is composed of
lipids, lipoproteins, and lipopolysaccharide (LPS)
150
Does the cell wall of gram-negative bacteria have teichoic acids
no
151
In gram-negative cell walls peptidoglycan is about ______% of cell walls weight
5-10%
152
The periplasmic space of gram-negative cell walls may constitute ______% of cell volume
20-40%
153
the periplasmic space of gram-negative cell walls have many enzymes present such as
hydrolytic enzymes, transport proteins and other proteins
154
The outer membrane of gram-negative cell walls lays outside the
thin peptidoglycan layer
155
_____ connect outer membrane to thin peptidoglycan layer of gram-negative bacteria
Braun's Lipoproteins
156
Lipopolysaccharide (LPS) consists of three parts. What are they
- Lipid A
- Core polysaccharide
- O side chain (O antigen)
157
Lipid A is embedded in the
outer membrane
158
Core polysaccharide, O side chain extend
out from the cell
159
Importance of LPS
- Contributes to negative charge on cell surface
- Helps stabilize outer membrane structure
- May contribute to attachment to surfaces and biofilm formation
- Creates a permeability barrier
- Protection form host defenses (O antigen)
- Can act as an endotoxin (Lipid A)
160
What acts as an endotoxin in gram-negative bacteria
Lipid A
161
What is the function of the O antigen in gram-negative bacteria
protection from host defenses
162
The Gram-negative outer membrane is more permeable than plasma membrane due to presence of ______ and _____
Of porin protein and transporter proteins
163
Porin proteins in the outer membrane of gram-negative bacteria let ______ molecules (_____daltons) pass
small (600-700 daltons)
164
Solute concentration outside the cell is less than inside the cell
hypotonic environment
165
In a hypotonic environment water moves
into the cell and the cell swells
166
The function of the cell wall in a hypotonic environment is that it
protects the cell from lysis
167
Solute concentration outside the cell is greater than inside
Hypertonic environments
168
In a hypertonic environment water ______ the cell
leaves
169
what is plasmolysis
when the plasma membrane shrinks but the cell wall remains the same
170
_____ breaks the bond between N-acetyl glucosamine and N-acetylmuramic acid
Lysozyme
171
Penicillin inhibits _____ synthesis
peptidoglycan
172
Cells that lose a cell wall may survive in _____ environments
Isotonic
173
Mycoplasma does not produce a _____
cell wall
174
Mycoplasma does not produce a cell wall but their _______ is more resistant to osmotic pressure. Why
Plasma membrane. Because it has cholesterol in it
175
examples of cells without cell wall
- Protoplasts
- spheroplasts
- Mycoplasma
176
Archaeal cell walls lack peptidoglycan but some have ______ also called ____
pseudopeptidoglycan, also called pseudomurein
177
Components outside of the cell wall
- Outermost layer in the cell envelope
- Glycocalyx
- capsules and slime layers
- S layers
- Aid in attachment to solid surfaces
- e.g. biofilms in plants and animals
178
Capsules and slime layers aid in attachment to _____
solid surfaces
179
Capsules are usually composed of
polysaccharides
180
Capsules are well organized and _____ removed form the cell
not easily
181
Are capsules visible via light microscope
yes
182
What are the protective advantages of capsules
- Resistant to phagocytosis
- Protect from desiccation
- Exclude viruses and detergents
183
Slime layers are similar to capsules except ____, _____ and ____
diffuse, unorganized and easily removed
184
Slime layers may aid in
motility
185
S layers are regularly structured layers of ____ or ____ that ____-
protein or glycoprotein that self-assemble
186
In gram-negative bacteria the S layer adheres to _____
outer membrane
187
In Gram-Positive bacteria the S layer is associated with the ________ surface
peptidoglycan surface
188
Functions of S layer
- Protect from ion and pH fluctuations, osmotic stress, enzymes, and predation
- Maintains shape and rigidity
- Promotes adhesion to surfaces
- Protects from host defenses
- Potential use in nanotechnology
- S layer spontaneously associates
189
Examples of external structures that extend beyond the cell envelope in bacteria
- Pili and fimbriae
| - Flagella
190
Function of external structures that extend beyond the cell envelope in bacteria
- Protection
- Attachement to surfaces
- Horizontal gene transfer
- cell movement
191
short, thin, hairlike, proteinaceous appendages (up to 1,000/cell) that can mediate attachment to surfaces
Fimbriae (s. fimbria) ; Pili (s. Pilus)
192
Some (type ____ fimbriae) required for twitching motility or gliding motility that occurs in some bacteria
IV
193
Long, thicker, and less numerous (1-10/cell) and is required for conjugation (mating)
sex pili (s. Pilus)
194
Genes for formation of sex pili are found on
plasmid
195
Threadlike, locomotor appendages extending outward from plasma membrane and cell wall
Flagella
196
Functions of Flagella
- Motility and swarming behavior
- Attachment to surfaces
- May be virulence factors
197
A bacterial flagella has an ultrastructure composed of ____ parts
three
198
What are the three parts of a bacterial flagella
- Filament
- Hook
- Basal body
199
Bacterial flagella are thin, rigid protein structure that cannot be observed with bright-field microscope unless specially
stained
200
The filament of bacterial flagella extends form _____ to the ___
cell surface to the tip
201
The filament of bacterial flagella is a ____, ____ cylinder of ______ protein
Hollow, rigid cylinder of flagellin protein
202
The hook of bacterial flagella links ____ to ____
filament to basal body
203
The basal body of flagella is a series of ___ that _____
rings that drive flagellar motor
204
Flagellar synthesis
- Complex process involving many genes/gene products
- New flagellin molecules transported through the hollow filament using type III-like secretion system
- Filament subunits self-assemble with help of filament cap at time, not base
205
New flagellin molecules transported through the hollow filament using _____- like secretion system
Type III
206
Filament subunits self-assemble with help of _____ at ___, not ___
filament cap at tip, not base
207
Monotrichous
One flagellum
208
Polar flagellum
flagellum at end of cell
209
Amphitrichous
one flagellum at each end of cell
210
Lophotrichous
cluster of flagella at one or both ends
211
Peritrihous
Spread over entire surface of cell
212
bacteria and archaea have direct movement. Name them
Directed
- Flagellar movement
- Spirochete motility
- Twitching motility
- Gliding motility
213
What is movement toward chemical attractants such as nutrients, and away from harmful substances called
Chemotaxis
214
Bacteria and archaea move in response to ____, ____, _____, and ___
temperature, light, oxygen, osmotic pressure, and gravity
215
In general a bacterial flagellum counterclockwise (CCW) rotation causes _____ motion (run)
forward
216
In general a bacterial flagellum clockwise rotation (CW) causes
disrupts run causing cell to stop and tumble
217
____ and ____ create a channel through which protons can flow. This causes the flagellum to rotate
MotA and MotB
218
Bacterial flagellum is a ____ part motor producing torque
2
219
The rotor of the flagellum is composed of _____ and ____, which turn and interact with strator
C (FliG protein) ring and MS ring
220
The Strator of a flagellum is composed of _____ and _____ proteins
Mot A and Mot B
221
The strator of flagellum form channel through ___
plasma membrane
222
Protons move through ____________ using energy of proton motive force
Strator (Mot A and Mot B)
223
Torque powers rotation of the _____ and ____
basal body and filament
224
Spirochete motility
- Multiple flagella form axial fibril which winds around the cell
- Flagella remain in periplasmic space inside outer sheath
- Corkscrew shape exhibits flexing and spinning movements
225
Twitching and Gliding motility may involve _____ and ___-
type IV pili and slime
226
Explain twitching motility
- Pili at ends of cell
- short, intermittent, jerky motions
- cells are in contact with each other and surface
227
Explain gliding motility
smooth movements
228
Movement toward a chemical attractant or away form a chemical repellent
chemotaxis
229
changing concentrations of chemical attractants and chemical repellent bind _____ of chemosensing system
chemoreceptors
230
in presence of attractant tumbling frequency is _________ and runs in direction of attractant are ____
intermittently reduced, longer
231
Behavior of bacterium is altered by _____ concentration of chemical
temporal
232
Chemotaxis away from a repellent involves ____ tumbling frequency and run is intermittently ___
longer, reduced
233
Complex, dormant structure formed by some bacteria
Bacterial endospore
234
Endospores are resistant to
- heat
- Radiation
- Chemicals
- Desiccation
235
Endospore structure is a spore surrounded by thin covering called _____
exosporium
236
thick layers of ____ form the spore coat
protein
237
The cortex, beneath the coat of the endospore, is made of ______
thick peptidoglycan
238
The core of the endospore has ____ and ___
nucleoid and ribosomes
239
What makes an endospore so resistant
- calcium (complexed with dipicolinic acid)
- Small, acid-soluble, DNA-binding proteins (SASPs)
- Dehydrated core
- Spore coat and exosporium protect
- DNA repair enzymes
240
Process of endospore formation
Sporulation
241
Sporulation occurs in
hours (up to 10 hours)
242
Sporulation normally commences when growth ___ because of lack of ____
ceases, nutrients
