Lecture 3 Flashcards
1
Q
what bacterial shapes are the most common? (2)
A
cocci and bacilli
2
Q
shape and arrangement: bacilli (s. bacillus)
A
rods
3
Q
shape and arrangement: coccobacilli
A
very short rods (kinda chubby)
4
Q
shape and arrangement: vibrios
A
resemble rods but comma shaped
5
Q
shape and arrangement: spirilla (s. spirillum)
A
rigid helices
6
Q
shape and arrangement: spirochetes
A
flexible helices
7
Q
bacteria that divide and form grape-like structures are called…
A
staphylococci
8
Q
gram-negative bacterium: envelope contains… (3)
A
- cell wall
- periplasm
- inner cell membrane
9
Q
bacterial cells hold DNA in a _____
A
nucleoid
10
Q
nucleoid
A
non-membranous bound area of the cytoplasm that contains the chromosome in the form of looped coils
11
Q
T/F Some bacteria have cytoplasmic organelles
A
true- but RARE
12
Q
in gram negative bacteria, the cell membrane directly surrounding the cytoplasm is the _____ membrane
A
inner
13
Q
in gram positive bacteria, the cell membrane directly surrounding the cytoplasm is the _____ membrane
A
only
14
Q
bacteria have what outside of their membrane?
A
a cell wall
15
Q
in gram negative bacteria, there is what outside of the cell wall?
A
another membrane
16
Q
many bacteria have a _____
A
flagella
17
Q
flagella
A
rotary swimming motor
18
Q
the cell membrane is made of a double layer of phospholipids known as the…
A
phospholipid bilayer
19
Q
membrane proteins serve numerous functions including…(3)
A
- structural support
- detection of environmental signals
- energy storage
20
Q
how are proteins locked into the phospholipid bilayer?
A
they have hydrophobic and hydrophilic regions
21
Q
the bacterial cell wall is a network of _____ and _____
A
sugars and peptides
22
Q
the bacterial cell wall confers…
A
shape and rigidity on the bacterial cell
23
Q
what is the structure of peptidoglycan
A
sugar chains linked to each other by short polymers of amino acids
24
Q
vancomycin and penicillin block…
A
peptide addition and crosslink formation
25
Sacculus is made of _____ aka _____
peptidoglycan, murein
26
what is unique to bacteria?
petidoglycan
27
what are excellent targets for antibiotics?
the enzymes responsible for peptidoglycan synthesis, since it is unique to bacteria
28
penicillin inhibits the _____ that cross-links the peptides
transpeptidase
29
Vancomycin prevents _____ formation by binding to terminal D-Ala D-Ala dipeptide
cross-bridge
30
do all species of bacteria have a capsule?
no
31
what is the capsule of a bacterium made from? (if present)
polysaccharides
32
do all species of bacteria have an S-layer?
no
33
what is the S layer in gram-positive bacteria composed of? (if present) (2)
protein and glycoprotein
34
what is the thick wall of gram- positive bacteria composed of? (3)
- 9-amino acid crosslinks in petidoglycan
- teichoic acids
- protein channels
35
what does teichoic acid provide to the thick cell wall of gram-positive bacteria?
strength
36
which two bacteria, in particular, have very complex cell envelopes? (2)
Mycobacterium tuberculosis
Mycobacterium leprae
37
what is unusual about the cell envelop of M. tuberculosis and M. leprae? (2)
membrane lipids: mycolic acids
unusual sugars: arabinogalactans
38
M. tuberculosis and M. leprae are "gram-_____" envelope structure, but _____ _____ prevents the uptake of gram stain
positive; mycolic acid
39
some gram-positive bacteria (2)
- Bacillus anthracis
- staphylococcus
40
some gram-negative bacteria (2)
e. coli; salmonella
41
general structure of a gram-positive wall (4)
1. capsule
2. s layer
3. thick cell wall
4. plasma membrane
42
general structure of a gram-negative bacteria wall (4)
1. capsule
2. outer membrane
3. thin cell wall
4. plasma membrane
43
what is the outer membrane of a gram-negative bacteria composed of?
lipopolysaccharide
44
lipopolysaccharide is also know as...
endotoxin
45
where in the outer membrane do you find lipopolysaccharide?
in the outer leaflet only
46
what makes most gram-negative bacteria tougher and harder to kill?
the outer membrane composed of lipopolysaccharide
47
what is the thin cell wall of gram-negative bacteria composed of?
4-amino acid crosslinks in peptidoglycan
48
LPS aka...
lipopolysaccharide
49
three components of lipopolysaccharide (LPS)
- lipid A
- core polysaccharide
- O side chaine (O antigen)
50
what portion of LPS is embedded in the outer membrane of bacteria?
lipid A
51
what portions of LPS extend out from the cell?
the core polysaccharide and O side chain
52
why is LPS important? (4)
- contributes to negative charge on cell surface
- helps stabilize outer membrane structure
- creates a permeable layer
- protect from host defenses
53
what may contribute to the attachment of some bacteria to surfaces to create biofilms?
LPS
54
what can act as an endotoxin?
lipid A, it is a PAMP (pathogen associated molecular pattern)
55
compare and contrast positive and gram-negative cell envelops in the following categories:
- gram stain color
- peptidoglycan layer
- number of membranes
- periplasmic space
- LPS
- teichoic acids
Gram positive: purple; thick peptidoglycan layer; one membrane; no periplasmic space; no LPS; does have teichoic acids
gram-negative: pink/red; thin peptidoglycan; two membranes; large periplasmic space; does have LPS; no teichoic acids
56
how does the gram stain, stain?
the crystal violet forms crystals with iodine in the cells
57
gram-stain mechanism: gram-positive (2)
- alcohol dehydrates peptidoglycan
- crystal violet-iodine crystals do not leave the cell
58
gram-stain mechanism: gram-negative (2)
- alcohol dissolves outer membranes and leaves holes in peptidoglycan
- crystal violet-iodine crystals wash out
59
which type of toxins do gram-positive bacteria primarily produce?
exotoxins
60
which type of toxins do gram-negative bacteria primarily produce?
endotoxins
61
are gram negative or positive bacteria susceptible to lysozymes, penicillin, and sulfonamide?
gram-positive
62
The LPS that is found in the outer membrane of gram-negative bacterial is also known as a...
endotoxin
63
What is found in the cell wall of a gram-positive bacterium but N NOT in that of a gram-negative bacterium?
teichoic acids
64
mycoplasmas lack what?
cell walls
65
mycoplasmas contain _____ in the plasma membrane
sterols
66
why are mycoplasmas resistant to penicillin? (3)
they are wall-less or have walls of pseudomurein (no peptidoglycan)
67
_____ breaks the bond between N-acetyl glucosamine and N _-acetylmuramic acid
lysozyme
68
_____ inhibits petidoglycan synthesis
penicillin
69
what happens to bacterial cells that are treated with lysozyme or penicillin that are transferred to a hypotonic solution?
they lyse
70
hypotonic environments (2)
- solute concentrations outside the cell is less than inside the cell
- water moves into the cell causing it to swell
71
hypertonic environments (3)
- solute concentration outside the cell is greater than the inside
- water leaves the cell
- plasmolysis (lysis) occurs
72
four bacterial cytoplasmic structures
- cytoskeleton
- nucleoid and plasmids
- ribosomes
- inclusions
73
how are bacterial cytoskeletal proteins revealed?
by gene defects that drastically alter the cell shape
74
shape-determining proteins: FtsZ
forms a Z-ring in spherical cells
75
shape-determining proteins: MreB
forms a coil inside rod-shaped cells
76
shape-determining proteins: CreS (crescentin)
forms a polymer along the inner side of crescent-shaped bacteria
77
nucleoid
single loop of double stranded DNA of bacteria (usually)
78
how are bacteria chromosomes compacted?
supercoiling
79
the nucleoid is attached to what portion of bacterial cells?
cell envelope; no membrane separated DNA from the cytoplasm
80
how do E.coli necleoid appear?
clear regions that exclude the ribosome and contain the DNA strands
81
what does RNA polymerase do?
transcribes DNA to mRNA aka transcription
82
what do ribosomes do?
translates RNA to protein
83
transcription and translation processes occur _____ in prokaryotes
simultaneously
84
isotonic solutions
solute concentration is the same inside and outside of the cell, causing no net movement
85
the nucleoid forms what within the cells?
loops or domains
86
bacterial DNA is supercoiled by...
DNA-binding proteins
87
extrachromosomal DNA
usually small, closed, circular DNA molecules
88
T/F: Plasmids do not exist and replicate independently of the bacterial chromosome
FALSE: they do replicated independently where they are inherited during cell division
89
do plasmids contain genes that are essential to the host bacteria?
no; they contain a couple genes that are non-essential like conferring a selective advantage to the host
90
how are plasmids classified? (3)
- mode of existence
- spread
- function
91
what is the site of protein synthesis?
ribosome
92
S is what unit?
Svedberg unit
93
Svedburg units of bacterial and archaea ribosomes (3)
total = 70S
small subunit = 30S
large subunit = 50S
94
Svedburg units of eukaryotic ribosomes
total = 80S
small subunit = 40S
large subunit = 60S
95
bacterial ribosomal RNA Svedburg units
- 16S in small subunit
- 23S and 5S in large subunit
96
specialized structures for photosynthesis: cyanobacteria have _____
thylakoids
97
thylakoids contain what photosynthetic pigment?
chlorophyll
98
what are the ancestors of chloroplasts
thylakoids
99
thylakoids have what kind of inner membrane?
extensively folded
100
what do carboxysomes do?
fix carbon
101
some bacterial photosynthetic pigments are what color?
purple in the membranes
102
_____ proteins collect light energy
phycobilisome
103
storage granules
intracellular deposits of material
104
different types of bacteria sequester different materials like (4)
- glycogen
- PHB
- polyphosphate
- sulfur
105
different types of bacteria sequester different materials: glycogen for
energy
106
different types of bacteria sequester different materials: PHB
poly-hydroxybutyrate (a fatty acid polymer) for energy
107
different types of bacteria sequester different materials: polyphosphate
for storage and growth regulation
108
different types of bacteria sequester different materials: sulfur
for disposal; in bacteria that use H2S as an electron source
109
magnetosomes
membrane-embedded crystals of Fe3O4 fixation
110
what do magnetosomes do?
orient the swimming of magnetotactic bacteria
111
what is the outermost layer of the cell envelope of bacteria?
glycocalyx
112
glycocalyx (2)
- capsules and slime layers
- S layers
113
what does the glycocalyx do?
it aids in attachment to solid surfaces (think biofilms in plants and animals)
114
the capsule of bacteria is usually composed of _____
polysaccharides
115
T/F: the capsule is well organised and not easily removed from the cell
TRUE
116
capsules are visible using what kind of microscope?
light microscopes
117
what are the protective advantages of the bacterial capsule? (3)
- resistant to phagocytosis
- protects from desiccation (removal of moisture)
- excludes viruses and detergents
118
S layer
regularly structured layers of protein or glycoprotein that self-assemble
119
S layers may aid in _____
motility
120
in Gram-negative bacteria, the S-layer adheres where?
to the outer membrane
121
in Gram-positive bacteria, the S layer is associated with...
the peptidoglycan surface
122
nanotubes
intercellular connections that pass material from one cell to the next
123
specialized structures for cell attachment (2)
- fimbriae
- pili
both attach to cells surfaces
124
fimbriae and pili are made of thin filaments of a protein called _____
pilin
125
stalks attached to the cells surface form a _____
holdfast
126
stalks attached to cells surfaces are also an extension of...
the cell cytoplasm
127
secretion systems (stalks) attach cells to what three kinds of things?
- prey
- host
- potential mates
128
specialized structures for cell motility: flagella
long, helical protein filaments
129
flagella are filaments of a protein called _____
flagellin
130
where are some places flagella are attached to cells? (2)
the ends or over the whole cell
131
a sex pilus is similar to what type of secretion system?
IV secretions systems
132
the base of flagella resembles what type of secretion system?
type III
133
how do flagella move?
they rotate to propel the cell
134
PMF or _____ _____ _____ drives rotation clockwise or counterclockwise
proton motive force
135
chemotaxis
the directed migration of a cell in response to a chemical stimulus, such as a growth factor
136
attractants cause what kind of rotation in the flagella?
counterclockwise to push the cell forward or "run"
137
repellents cause what kind of rotation in the flagella?
clockwise rotation to 'tumble" or change the direction
138
runs and tumbles together cause...
"random walk"
139
receptors detect attractant concentrations of things like...(2)
sugars and amino acids
140
when attractant concentration increases, it prolongs...
the run, biasing the random walk causing a next movement of bacteria toward attractants
141
what kind of bacteria have endoflagella?
spirochetes
142
where are endoflagella anchored?
at one end of a cell
143
rotation of an endoflagella causes what?
the whole cell to move
144
axial filaments are also called what?
endoflagella
145
endospores, simply put are what?
resting cells
146
endospores are resistant to...(4)
environmental stress such as desiccation (loss of moisture), heat, radiation, and chemicals
147
what kinds of bacteria have endospores? (3)
- gram positive
- bacillus
- clostridium
148
sporulation
endospore formation
149
germination
return to a vegetative state
150
T/F: COmmon food preservation processes do not kill endospores
TRUE
151
endospores are of great practical importance where? (3)
in food, industrial, and medical microbiology
152
What structure protects pathogenic bateria from phagocytosis?
capsule
153
Molecules of extrachromosomal DNA are also known as what?
plasmids
154
Which structure allows a cell to survive adverse environmental conditions?
endospores
155
Prokaryotic ribosomes are composed of two subunits of what sizes?
30S + 50S
156
surface area to volume ratio problem
When the surface area to volume ratio is large, cells are supplied with ample nutrients to produce life.
When the surface area to volume ratio is low, cells are not able to supply themselves with enough nutrients to fuel all the internal complexes.
157
advantages of organelles: endomembranes
membranes around organelles increase membrane SA without increasing cell volume
158
advantages of organelles: enclosing certain metabolic activities
within a confined space allows for an increased concentration of enzymes and substrates allowing reactions to proceed faster
159
advantages of organelles: different conditions
endomembranes allow for different conditions within different organelles such as the acidic pH in lysozomes
160
advantages of organelles: protection
protects cytoplasm from harmful substances such as hydrolytic enzymes in lysosomes and peroxide in peroxisomes
161
compare and contrast: location of DNA in prokaryotic and eukaryotic cells
- Eukaryotic: nucleus
- Prokaryotic: nucleoid region in cytoplasm
162
compare and contrast: cell wall of eukaryotic and prokaryotic cells
- Eukaryotic: cellulose or chitin
- Prokaryotic: peptidoglycan
163
compare and contrast: internal membranes
- Eukaryotic: extensive membranous organelles
- Prokaryotic: uncommon
164
compare and contrast: flagella composition
- Eukaryotic: alpha and beta tubulin
- Prokaryotic: flagellin
165
cytoplasm
substance inside plasma and outside nucleus
166
cytosol
fluid portion of the cytoplasm
167
cytoskeleton (3)
microfilaments, intermediate filaments, and microtubules
168
cytoplasmic streaming
movement of cytoplasm throughout cells
169
non-membrane bound organelles (2)
- ribosomes
- centrosome
all other are membranous
170
nucleus
contain chromosomes
171
endoplasmic reticulum
transportation network
172
golgi complex
packaging and secretion of material for various purposes and lysosome creation
173
lysosome
holds digestive enzymes for intracellular digestion
174
vacuole
brings food into cells and provides support
175
mitochondrion
cellular respiration
176
chloroplast
photosynthesis
177
peroxisome
oxidation of fatty acids; destroys H2O2 (oxidize organic/toxic substances)
178
centrosome
consists of protein fibers and centrioles, and plays an important role in cell division
179
what kind of membrane is the nuclear membrane?
a double membrane
180
what are the nuclear pores of the nuclear membrane for?
transportation control
181
where are ribosomes found on the nucleus?
attached to the outside of the nuclear membrane
182
what is the center of the nucleus called?
nucleolus
183
which ribosome is in chloroplasts and mitochondria?
70S (similar to bacterial ribosome)
184
which ribosome is free in the cell, or attached to the ER in the cytoplasm?
80S (60S + 40S)
185
which endoplasmic reticulum has ribosomes attached?
rough ER
186
which ER is responsible for protein synthesis?
rough ER
187
which ER is responsible for lipid synthesis?
smooth ER
188
what is a membranous organelle made of cisternae stacked on each other?
golgi complex
189
the golgi complex is involved in...(3)
(1) modification, (2) packaging, and (3) secretion of materials for various purposes
190
lysosomes contain _____
hydrolases
191
hydrolases
enzymes which hydrolyze molecules and function best under slightly acidic conditions
192
how do lysosomes maintain an acidic environment?
by pumping protons into their interior
193
the inner membrane of the mitochondria is folded as _____
cristae
194
T/F: the mitochondria do not have their own genome
FALSE- they do have their own genome
195
what kind of ribosome do mitochondria have?
70S
196
the outer membrane of the mitochondrial membrane have that is similar to gram-negative bacteria?
porins (for diffusion of ions and water)
197
which membrane of the mitochondria is the location of enzymes and electron carries for oxidative phosphorylation?
the inner membrane
198
the matrix enclosed by the inner membrane of the mitochondria contains...(4)
- ribosomes
- mitochondrial DNA
- enzymes of the TCA cycle
- enzymes for catabolism of fatty acids
199
what is the site of photosynthetic reactions?
chloroplast
200
chloroplast
pigment-containing organelles observed in plants and algae
201
T/F: chloroplast have a double membrane
TRUE
202
Endosymbiotic Theory (4)
eukaryotic cells from from prokaryotic cells
- mitochondria were bacteria and chloroplast were cyanobacteria (photosynthetic bacteria)
- these were engulfed by other species
- ended up living inside (endosymbiosis)
203
evidence for the endosymbiotic theory (3)
- mitochondria/chloroplast resemble bacteria in size, shape, and their ability to replicate via binary fission
- circular DNA genome
- 70S ribosome
204
T/F: archaea are bacteria
FALSE - they are not bacteria
205
bacteria and archaea are similar in...(2)
size and shape
206
archaeal ribosomes are similar to _____ ribosomes
eukaryotic
207
generally, where do archaea live?
harsh environments
208
_____S rRNA gene sequence is found in all cellular organisms
16
209
The plasma membrane of eukaryotes contains all of the following except:
- phosphoglycerides
- sphingolipids
- sterols
- peptidoglycan
peptidoglycan
210
What is a function of the mitochondrion? (3)
- TCA cycle enzymatic reactions
- electron transport
- ATP synthesis
211
Prokaryotic ribosomes are composed of two subunits of what size?
30S and 50S
