Slide deck 2 Flashcards
1
Q
what are the ribosomal subunits in bacterial RNA?
A
16S is the small subunit, and the large subunit is split into two (23S and 5S)
2
Q
T/F: bacterial ribosomes are the same as archaeal.
A
false they are the same size but differnet sequence.
3
Q
What features does archaea have in common with bacteria?
A
highly diverse in morphology, physiology, reproduction, and ecology
same/similar genes for metabolism
both can preform methanogenesis
4
Q
where were archaea first discovered?
A
hot springs
5
Q
what are archaea best known for?
A
growth in extreme environments (extremeophiles)
6
Q
what sequence is critical in archaea?
A
cell walls and membrane structures
7
Q
what kind of RNA is unique in archaea?
A
rRNA
8
Q
what is the plasma membrane?
A
bilipid layer that encompasses the cytoplasm
9
Q
what is the absolute requirement for all living organisms?
A
plasma membranes
10
Q
what is the biggest difference between bacterial and eukaryotic plasma membranes?
A
in bacteria there is no cholesterol in the membrane
11
Q
how does the plasma membrane interact with the external environment?
A
- it contains receptors for detection and response to chemicals in the surroundings
- transport systems
- metabolic processes
12
Q
what kind of linkage does bacteria and eukaryotes have in their membranes?
A
ester linkages
13
Q
what kind of linkage does archaea have in their membranes?
A
ether or diglycerol tetraethers
14
Q
what are the three main shapes of bacteria?
A
cocci (ball)
rods (pill shaped)
spiral (curved bacilli)
15
Q
T/F: spiral bacteria only has one curve.
A
false it can have many curves and even comes in spring-shape
16
Q
What is the name of the ring that forms during septum formation in cell division where is it found?
A
FtsZ, in most bacteria
17
Q
what does MreB do and where is it found?
A
maintains shape by positioning peptidoglycan synthesis machinery, found in most rods
18
Q
how does MreB work?
A
spirals around the interior and wherever it touches more cell wall will be produced.
19
Q
how does FtsZ form in MreB spirals inside the bacteria?
A
it will form between one of the loops causing MreB to become a circle
20
Q
what is another gene that controls curvature in Vibrio?
A
crescentin and CrvA
21
Q
what is the purpose of CrvA in conjunction with crescentin?
A
it slows the growth of the cell membrane and cell wall.
22
Q
how much smaller approximately is bacterial cells compared to eukaryotic cells?
A
about tenfold
23
Q
what kind of bacteria does not have a cell wall?
A
mycoplasma
24
Q
what kind of bacteria is the smallest?
A
mycoplasma
25
T/F: bacteria may exist in communities.
true they are unicellular and stick together
26
why are sphere shapes so much smaller?
it is harder to get nutrients in larger cells
27
why are rod shapes typically bigger than sphere?
because large sizes and odd shapes may be a good method of protection from predation
28
what is the important function in terms of bacterial size?
size/volume
29
T/F: a rod bacteria with the same volume as a spherical cell has a smaller S/V ratio.
false it will have a larger
30
how do really big bacteria survive?
they have fluid filled vacuoles that push out all the important bits to the membrane allowing the bigger size
31
what are the membrane bound compartments called in Thiomargarita magnifica?
pepins
32
T/F: pepins are membrane bound organelles.
false, bacteria does not have membrane bound organelles
33
what different methods are there for nutrient uptake?
- passive diffusion
- facilitated diffusion
- primary and secondary active transport
- group translocation
34
what does ABC mean in terms of active transport?
ATP-binding cassette
35
What does ABC transporters consist of?
2 hydrophobic membrane spanning domains, 2 cytoplasmic associated ATP-binding domains, and a substrate binding domain.
36
what is the difference between active transporters in eukaryotes and bacteria/archaea?
in eukaryotes the molecule cannot by itself bind to the transporter and get across it needs to be bound by a protein that is excreted by the environment
37
how do secondary active transporters work?
using the ion gradient to cotransport substances
38
what is symport?
two substances moving in the **same direction** across the membrane
39
what is antiport?
this is two substances moving in the **opposite direction**
40
What is group translocation?
energy dependent transport that chemically modifies molecule as it is brought into cells
41
what are the best translocation system? what is it for?
phosphoenolpyruvate, sugar phosphotransferase system
42
T/F: microorganisms require iron
true
43
what issue occurs when uptaking iron?
it is very insoluble so uptake is difficult
44
what is secreted to help uptake iron?
siderophores
45
what do siderophores do?
it complexes with ferrec ions
46
how are siderophones taken into the cells?
transported via ABCs
47
Bacterial cell walls help protect cell from _____ and _____
osmotic lysis and toxic materials
48
how are bacterial cell walls bad for us?
the cell wall can ajoin to the host cell inputting new DNA and evade immune responses
49
what is the very basic function of the cell wall?
maintains the shape of the bacteria
50
what is an alternate name for murein?
peptidoglycan
51
what is the peptidoglycan on a bacteria?
rigid structure lying just outside the cell plasma membrane
52
T/F: gram negative bacteria have a thick peptidoglycan and gram positive has thin peptidoglycan.
false the opposite
53
what colour does gram-positive bacteria stain to be?
purple
54
what colour does gram-negative bacteria stain to be?
stain pink or red
55
what is the structure of peptidoglycan?
meshlike polymer of identical subunits forming long strands
56
what are the two alternating sugars in peptidoglycan structures?
N-acetylglucosamine (NAG)
N-acetylmuramic acid (NAM)
57
what does NAM have?
they have a peptide side chain
58
what are the peptide side chains mostly consisting of? Why?
mostly of D-amino acids which are more resistant to proteases
59
what connects the peptide side chain?
peptide interbridge
60
what is the shape of gram positive peptidoglycan strands?
generally helical binding not only below but to each side binding to other helicals.
61
what kind of interbridges are in gram positive vs. gram negative?
- gram positive is made of a single peptide bridge binding D-Ala to DAP
- gram negative is made of a peptide bridge of Gly from D-Ala to L-Lys
62
what does the peptidoglycan help maintain and generally do?
helps maintain cell envelope, protects from environmental substances, and bind to a host cell
63
where is the peptidoglycan located in reference to the plasma membrane?
outside of the plasma membrane
64
what does gram positive bacteria have a layer of on its peptidoglycan?
a layer of proteins on the surface
65
what does the cell wall contain?
lipoteichoic and techoic acids (negatively charged)
66
what acids keep the cell wall and cell membrane together?
lipoteichoic acid and techoic acid
67
which specific acid connects the cell wall to the plasma membrane?
lipoteichoic acid
68
T/F: the periplasm contains the most proteins.
false contains the least
69
what type of bacteria secretes enzymes? what kind of enzymes?
gram positive and exoenzymes
70
what do exoenzymes do?
aid in degredation of large nutrients
71
what type of bacteria has a more complex cell wall structure?
gram negative
72
what are the three layers of gram negative cell walls?
plasma membrane -> peptidoglycan -> outer membrane
73
what is the space between the plasma membrane and outer membrane called?
periplasmic space
74
what is the outer membrane composed of?
lipids, lipoproteins, and lopopolysaccharides
75
T/F: gram negative cells walls do not contain teichoic acids.
true
76
what connects the outer membrane to the peptidoglycan?
Braun's lipoproteins
77
how does the periplasmic space differ from gram-positive cells?
- this constitutes 20-40% of cell volume
- many enzymes present in the periplasm
- hydrolytic enzymes, transport proteins, and other proteins
78
on the outer membrane what is the specific structure to gram negative proteins?
hair-like structures made of lypopolysaccharides made of long sugar chains with a lipid end
79
what are the three parts of the lipopolysaccharides?
the O-antigen (O-side chain), core polysaccharides, and the lipid A
80
what is the O-Antigen?
this is the host defense
81
what is the core polysaccharides?
negatively charged core sugars
82
what is lipid A?
this is an endotoxin embedded in the outer cell membrane for stabilization
83
T/F: endotoxins are how botulism is excreted.
false, endotoxins are generally not harmful, botulism is secreted by exotoxins
84
T/F: gram negative bacteria is less permeable in the outer membrane.
false it is more permeable
85
why is the plasma membrane more permeable?
the presence of porin (OmpF)
86
what do porins do?
they form channels to let small molecules pass
87
what kind of bacteria is covered in porins and why?
deep sea bacteria for allow for fluid transfer
88
In what type of bacteria is violet/purple and why?
gram-positive bacteria, which has a shrinkage of pores in the peptidoglycan layer preventing crystal violet loss during decolorization step
89
what are hypotonic environments?
- solute concentration outside cell less than inside
- water moves into the cell and cell swells
- cell wall protects from lysis
90
what is it called when a bacteria cell is under hypotonic conditions?
turgid or normal
91
what is a hypertonic environment?
- solute is at greater concentration outside of the cell.
- water leaves the cell
- plasmolysis occurs
92
what happens when a cell with a cell wall is under hypertonic conditions?
the cell starts to pull away from the cell wall and is plasmolyzed
93
what is the mycoplasma?
this cell wall-like structure but is actually a membrane that is more resistant to osmotic pressure.
94
what is different in mycoplasma?
minor tweaks in the genome
95
what enzyme breaks bonds between NAM and NAG?
lysozyme
96
what drug inhibits peptidoglycan synthesis?
penicillin
97
when cells are treated with penicillin and lysozyme how are they lysed?
when transferred into a hypotonic medium
98
What is a capsule made of?
polysaccharides
99
100
what is a capsule?
this is an extra layer surrounding the cell
101
how are capsules seen?
they are visible with a light microscope
102
what are the advantages of a capsule?
- resistance to phagocytosis
- protection from antibiotics
- protection from desiccation
103
what is the differences between slime layer and capsules?
slime layers are:
- unorganized
- easily removed
104
what is the purpose of a slime layer?
facilitating mobility
105
T/F: capsules are always found in archaea.
false, they are rarely found
106
what is the alternative structure to a capsule?
S Layers
107
In gram-negative bacteria what is the S layer associated with?
the outer membrane
108
In gram-positive bacteria what is the S layer associated with?
peptidoglycan
109
what is the function of an S layer?
- protection from ion and pH fluctuations, osmotic stress, enzymes, and predation
- maintaining shape and rigidity
- promoting adhesion to surfaces
- protection from host defenses
110
T/F: archaea do not have peptidoglycan.
true
111
What are archaeal cell walls made of?
N-acetylalosaminuronic acid and N-Acetylglucosamine
112
what is the structure that is like peptidoglycan in archaea?
pseudomurein
113
What is the intracytoplasmic membrane
plasma membrane infoldings
114
where are plasma membrane infoldings found? and why?
- photosynthetic bacteria
- bacteria with high respiratory activity
because they have many enzymes with a high work load
115
How is storage worked into bacteria?
they store nutrients and metabolic end products in things that look like organelles but not membrane-bound they are just insoluble or have a protein shell
116
what are common carbon storage item(s) in bacteria?
PHB
117
how is phosphate stored in bacteria?
polyphosphate
118
how are amino acids stored in bacteria?
cyanophycin granules
119
how is sulphur stored in bacteria?
sulphur granules
120
where are gas vacuoles found?
aquatic photosynthetic bacteria and archaea
121
what do gas vacuoles do?
provide buoyancy
122
how are gas vacuoles contained?
by a protein wall that surrounds them.
123
what is the purpose of magnetosomes?
cause cells of magnetotactic bacteria to passively align and swim along the Earth's magnetic field lines, as miniature motile compass needles
124
where are magnetosomes found?
in aquatic bacteria
125
T/F: the nucleoid is membrane bound.
false
126
what is held in the nucleoid?
chromosomes and associated proteins
127
T/F: all DNA in bacteria is circular
false some may have linear but circular is default
128
how many closed circular double stranded DNA molecules in the nucleoid?
1
129
what aids in folding?
supercoiling and the nucleoid proteins
130
what is extrachromosomal DNA?
usually small, closed circular DNA molecules
131
what are plasmids?
extrachromosomal DNA
132
how do plasmids replicate?
independently of chromsomes and entirely separate from the main genome
133
when are plasmids inherited?
during cell division
134
what are episomes?
Episomes or plasmids are lengths of DNA existing either in the cytoplasm or attached to the chromosome of a bacterium
135
how are plasmids classified?
by extra features, resistances etc
136
T/F: bacteria can take up DNA from their environment
true
137
what forms the lipid bilayers in archaea?
glycerol diethers
138
what forms the lipid bilayers in bacteria?
ester-linked phospholipids
139
what are cell wall constituents of bacteria?
peptidoglycan
140
T/F: all bacteria have a cell wall
false some don't
141
T/F: archaea always lack peptidoglycan.
true
142
how do archaea make their cell walls?
some consist of s-layer only, others combine S-layer with polysaccharides or proteins or both
143
