C1-C7 Flashcards
1
Q
typically contain
genes that are not essential but often confer some special property
on the cell (such as a unique metabolism, or antibiotic resistance).
A
plasmid
2
Q
Many prokaryotic cells can also exchange genes with
neighboring cells, regardless of their species, in the process of
A
HGT
3
Q
has a spiral shape but which differs from spirilla because its cells are flexible, whereas cells of spirilla are rigid.
A
spirochete
4
Q
More than 90% of cultivated bacteria belong to one of only four phyla:
A
Actinobacteria, Firmicutes,
Proteobacteria, and Bacteroidetes.
5
Q
The domain Archaea consists of five described phyla:
A
Euryarchaeota, Crenarchaeota, Thaumarchaeota, Nanoarchaeota, and
Korarchaeota
6
Q
hyperthermophile; high temp; archaea; undersea hydrothermal vents; 90C-106C-122C
A
Methanopyrus kandleri
7
Q
Low temp; Psychrophile; Bacteria; Sea ice; -12°C - 5°C -10°C
A
Psychromonas ingrahamii
8
Q
pH;Low; Acidophile;Archaea; Acidic; hot springs; -0.06- 0.7( thermophile optimal at 60C) - 4
A
Picrophilus oshimae
9
Q
pH; High; Alkaliphile; Archaea; Soda lakes; 8.5 - 10 (extreme halophile optimal at 20% NaCl) -12
A
Natronobacterium gregoryi
10
Q
Pressure;Barophile (piezophile); Bacteria ;Deep ocean sediments;
500 atm- 700 atm (pyschrophile optimal at near 4C) -71000 atm
A
Moritella yayanosii
11
Q
Salt (NaCl) ; Halophile; Archaea; Salterns; 15%- 25%- 32% (saturation)
A
Halobacterium salinarum
12
Q
He showed that Beggiatoa
are able to grow in the absence of organic nutrients, and that their
growth requires only inorganic substances (compounds lacking
carbon–carbon bonds);the first to
define chemolithotrophy
A
Sergei Winogradsky
13
Q
he enriched for and ultimately isolated the
anaerobic nitrogen-fixing bacterium Clostridium pasteurianum, becoming the first to demonstrate the process of nitrogen fixation;
A
Sergei Winogradsky
14
Q
used a similar technique to Winogradsky to shortly thereafter
to isolate the first aerobic nitrogen-fixing bacterium, Azotobacter; also the first person to observe a virus.
A
Martinus Beijerinck
15
Q
worked with a virulent strain of Streptococcus pneumoniae,
a cause of bacterial pneumonia in both humans and mice. This
strain, strain S, produced a polysaccharide coat (that is, a capsule) that caused cells to form smooth colonies on agar
media and conferred the ability to kill infected mice.
A
Frederick Griffith ; Griffith’s experiment
16
Q
The sugar backbone of peptidoglycan is composed of alternating repeats
of two modified glucose residues called
A
N-acetylglucosamine and
N-acetylmuramic acid joined by a b-1,4 linkage
17
Q
composed of glycerol phosphate or ribitol phosphate with attached molecules of glucose or
d-alanine (or both)
A
Teichoic acids
18
Q
Some teichoic acids are covalently bonded to membrane lipids
rather than to peptidoglycan, and these are called
A
lipoteichoic acids
19
Q
an enzyme that destroys peptidoglycan and its MOA
A
Peptidoglycan can be destroyed by lysozyme, an enzyme that
cleaves the glycosidic bond between N-acetylglucosamine and
N-acetylmuramic acid
20
Q
Most Archaea lack a polysaccharide containing cell wall and instead have an
A
S-layer
21
Q
Chemical structures not found in Bacteria. For example, the cell walls of certain methane-producing Archaea (methanogens) contain a polysaccharide called
A
pseudomurein
22
Q
archaea’s pseudomurein is structurally remarkably similar to bacteria’s
A
peptidoglycan
23
Q
difference of pseudomurein to peptidoglycan
A
backbone of pseudomurein is formed from alternating repeats of N-acetylglucosamine (also present in peptidoglycan) and N-acetyltalosaminuronic acid; the latter replaces the N-acetylmuramic
acid of peptidoglycan. Pseudomurein also differs from peptidoglycan in that the glycosidic bonds between the sugar derivatives are b-1,3 instead of b-1,4, and the amino acids are all of the L stereoisomer
24
Q
a space of about 15 nm located
between the outer surface of the cytoplasmic membrane and the inner surface of the outer membrane
A
periplasm
25
Many prokaryotic ( ie Heliobacterium modesticaldum) and eukaryotic microbes accumulate inorganic
phosphate (PO4
3-) in the form of
polyphosphate granules
26
Many gram-negative Bacteria and several Archaea oxidize reduced
sulfur compounds, such as hydrogen sulfide (H2S); these organisms
are the “sulfur bacteria,” discovered by
Sergei Winogradsky
27
For example, the unicellular cyanobacterium
Gloeomargarita forms intracellular granules which are carbonate mineral that contains barium, strontium, and magnesium
bensonite granules
28
most dramatic examples of gas-vesiculate
microbes are those cyanobacteria that form massive accumulations
called
blooms
29
the flagella are attached at one or both ends of a cell
polar flagellation
30
When a tuft of flagella emerges from both poles of the
cell, flagellation is called
amphitrichous
31
flagella are inserted around the cell surface.
peritrichous flagellation
32
The idea that symbiotic bacteria are ancestors to the mitochondrion
and chloroplast is called the
endosymbiotic theory
33
ER; participates in
the synthesis of lipids and in some aspects of carbohydrate metabolism.
SER
34
ER; through the activity of its ribosomes, is a major
producer of glycoproteins and also produces new membrane material that is transported throughout the cell to enlarge the various membrane systems before cell division
RER
35
where products of the ER are chemically modified and
sorted into those destined for secretion versus those that will function in other membranous structures in the cell
golgi complex
36
are membrane-enclosed compartments that contain digestive enzymes that hydrolyze proteins, fats, and
polysaccharides; also function in degrading damaged cellular components and recycling these
materials for new biosyntheses; allows the cell’s
lytic activities to be partitioned away from the cytoplasm proper.
lysosomes
37
exergonic processes in which cells generate
free energy by transforming reactants into products
Catabolic pathways
38
endergonic processes in which the synthesis
of cellular material from simple precursors requires an input of
energy
Anabolic pathways a
39
More often, the movement of electrons from electron
donor to electron acceptor proceeds through a series of consecutive reactions at different locations within the cell. Hence, the cell needs soluble electron carriers such as
nicotinamide adenine dinucleotide (NAD+/NADH)
40
The most important energy-rich phosphate compound in cells is
ATP
41
Cells conserve energy by generating ATP through one of three fundamental mechanisms; energy rich bond of a substrate is hydrolyzed to directly drive the formation of ATP; dominant mechanism of energy conservation in
fermentative organisms
substrate-level phosphorylation
42
Cells conserve energy by generating ATP through one of three fundamental mechanisms;the movement of
electrons from an electron donor to an electron acceptor generates a proton motive force; PMF electrochemical gradient creates a force that is ultimately used to synthesize ATP;the defining feature of respiration
reactions and it is performed by diverse chemotrophic organisms
oxidative phosphorylation.
43
Cells conserve energy by generating ATP through one of three fundamental mechanisms; light energy is used to form the
proton motive force that powers ATP synthesis and is the dominant
mechanism of energy conservation in phototrophic organisms.
photophosphorylation.
44
the minimum energy required
for a chemical reaction to begin
activation energy
45
Catalysts function by lowering the activation energy of a reaction, thereby increasing the reaction rate. Catalysts have no
effect on the energetics or the equilibrium of a reaction but only
affect the rate at which a reaction proceeds. Most cellular reactions
will not proceed at significant rates without catalysis.
The major catalysts in cells are
enzymes
46
a form of anaerobic catabolism in which organic compounds both donate electrons and accept electrons, and redox
balance is achieved without the need for external electron acceptors.
fermentation
47
a form of aerobic or anaerobic catabolism in which an electron donor, which can be either organic or inorganic, is oxidized using an external electron acceptor such as O2 or some other compound.
respiration
48
A nearly universal pathway for the catabolism of glucose; oxidation to pyruvate
Embden–Meyerhof–Parnas pathway, better known as glycolysis,
49
The pathway by which pyruvate is oxidized to CO2 is called the
CAC
50
Some chemoorganotrophs can also grow on two-carbon (C2)
compounds by using the
glyoxylate cycle
51
The glyoxylate cycle is composed of several citric acid cycle enzymatic reactions plus two additional enzymes:
isocitrate lyase, which cleaves isocitrate into succinate and glyoxylate,
and malate synthase,
which converts glyoxylate and acetyl-CoA to malate
52
Cells using standard CAC reactions to grow on C3 compounds, such as pyruvate, are also unable
to regenerate oxaloacetate. However, carboxylation reactions allow cells growing on C3 compounds to regenerate oxaloacetate. this involves the enzymes:
pyruvate carboxylase or phosphoenolpyruvate carboxylase, which convert pyruvate or phosphoenolpyruvate into oxaloacetate (respectively),
53
are proteins that contain heme prosthetic groups
cytochromes
54
a nonheme iron–sulfur protein of low reduction potential (about -0.4 V) and an important component in H2production, contains an Fe4S4 cluster
ferredoxin
55
small hydrophobic redox molecules that lack a protein component. Because they are small and hydrophobic, they can move about within the membrane.
quinones
56
contain a derivative
of the vitamin riboflavin
flavoproteins
57
ETC; cause a conformational change within the complex
resulting in transport of 4 H+ across the membrane
complex I
58
ETC;As an alternative entry point to the electron transport chain,
electrons from FADH2 enter through this complex; also called succinate dehydrogenase complex because the oxidation of succinate to fumarate in the citric acid cycle reduces FAD+ to FADH2, ultimately resulting in the reduction of this complex
complex II
59
ETC; The 2 e- from FADH2 are transferred through Complex II to ????, which accepts these 2 e- and 2 H+ from the cytoplasm to become ubiquinol (QH2)
ubiquinone (Q)
60
ETC; Complexes I,
II, and III are all linked by the
quinone pool
61
ETC; consists of the cytochrome bc1 complex
Complex III
62
ETC; Electrons enter Complex III from QH2 at the Qo site and they leave
when donated to cytochrome c. When QH2 donates its 2 e- to Complex III, it releases its two H+ outside of the cytoplasmic membrane, contributing to the proton motive force. However, QH2 carries 2 e- and cytochrome c only carries 1 e-. This difference creates an opportunity for conserving additional energy through a mechanism known
as the
Q cycle
63
ETC; functions as a periplasmic shuttle to transfer efrom Complex III to the high-redox-potential cytochromes a and a3
of Complex IV
cytochrome c
64
ETC; functions as the terminal
oxidase and reduces O2 to 2 H2O in the final step of the electron
transport chain.
complex IV
65
uses energy from the pmf to catalyze formation of ATP; process called oxidative phosphorylation when the pmf is generated by respiratory electron flow; while photophosphorylation when the
pmf is generated from light energy during phototrophy
ATP synthase
66
The first step in the Calvin cycle is catalyzed by the enzyme
ribulose
bisphosphate carboxylase, RuBisCO for short.
67
many Bacteria and Archaea can form ammonia
from gaseous dinitrogen (N2), a process called
nitrogen fixation
68
Nitrogen fixation is catalyzed by the enzyme complex:
Nitrogenase consisting of two proteins, dinitrogenase and dinitrogenase reductase
69
Nitrogenase is inhibited by oxygen (O2), but many nitrogen-fixing
bacteria are obligate aerobes; In certain cyanobacteria,
the nitrogenase enzyme is protected from O2 by its localization in a
differentiated cell called a
heterocyst
70
uses phosphoenolpyruvate, one of the intermediates of glycolysis, as a starting material and travels backwards through the glycolytic pathway to form glucose.
gluconeogenesis
71
Phosphoenolpyruvate can also be synthesized from a citric acid cycle intermediate which is the
oxaloacetate
72
the precursor of all purine
nucleotides
inosinic acid
73
the precursor of all pyrimidine nucleotides. formed from orotate following a decarboxylation and the addition of ribose
5-phosphate.
uridylate
74
major components of the cytoplasmic membrane and of
the outer membrane of gram-negative bacteria; can also be
carbon and energy reserves.
lipids
75
the backbone of microbial lipids.
fatty acids
76
Archaea do not contain fatty acids in their lipids but instead have
hydrophobic isoprenoid side chains
77
Fatty acids are biosynthesized two carbon atoms at a time by the
activity of a protein called
acyl carrier protein (ACP)
78
prepared by adding precise amounts of pure inorganic or organic chemicals to
distilled water. Therefore, the exact composition is known
defined media
79
made from digests of microbial, animal, or plant products, such
as milk protein (casein), beef (beef extract), soybeans (tryptic soy
broth), yeast cells (yeast extract), or any of a number of other highly
nutritious substances
complex media
80
contains compounds that inhibit the growth of some microorganisms but not others.
selective media
81
one to which an indicator (typically a dye) is
added, which reveals by a color change whether a particular metabolic reaction has occurred during growth
differential media
82
a series of steps by which microbes are transferred
between growth media without contamination.
aseptic technique
83
widespread in nature and are the most commonly studied microorganisms; found in the intestines of endothermic (warm-blooded) animals and in terrestrial
and aquatic environments in temperate and tropical latitudes.
mesophiles
84
a microbe with an optimal growth temperature of 15°C or lower, a maximum growth temperature below 20°C, and a minimum growth temperature of 0°C or lower.
pyschrophile
85
microbes that grow at 0°C but have optima of 20–40°C are called
psychotolerant
86
Organisms whose growth temperature optimum exceeds 45°C are called
thermophiles
87
those whose optimum exceeds 80°C are called
hyperthermophiles
88
Organisms that grow optimally at a pH value in the range termed
circumneutral (pH 5.5 to 7.9) are called
neutrophiles
89
organisms that grow best below pH 5.5 are called
acidophiles
90
Microorganisms showing pH optima of 8 or higher are called
alkaliphiles
91
the ratio of the vapor pressure of air in equilibrium with a substance or solution to the vapor pressure of pure water
water activity (aw)
92
Water diffuses from regions of higher water concentration (lower
solute concentration) to regions of lower water concentration
(higher solute concentration) in the process
osmosis
93
Microorganisms that inhabit marine environments almost
always show an NaCl requirement and grow optimally at the aw of
seawater, 0.98. they are called
halophiles
94
organisms which can tolerate
some level of dissolved solutes but grow best in the absence of the added solutes
halotolerant
95
These organisms require very high levels of NaCl, typically 15–30%,
for optimum growth and are often unable to grow at all at NaCl
concentrations below this.
extreme halophiles
96
Organisms able to live in environments
high in sugar are called
osmophiles
97
mcgs able to grow in very
dry environments (made dry by lack of water rather than by dissolved solutes) are called
xerophiles
98
When an organism is transferred from a medium of high aw to one
of low aw, it maintains positive water balance by increasing its internal solute concentration. This is possible either by
pumping solutes into
the cell from the environment or by synthesizing a cytoplasmic solute (compatible solutes )
99
mcsgs that can grow at full oxygen tensions (air is 21% O2) and respire O2 in their metabolism.
aerobes
100
are aerobes that can use O2 only
when it is present at levels reduced from that in air (microoxic conditions).
microaerophiles
101
mcgs that under the appropriate nutrient and culture conditions they can grow in the absence of O2.
facultative an/aerobes
102
Some organisms cannot respire oxygen and are called
anaerobes
103
mcgs that can tolerate O2 and grow in its presence even though they cannot respire
aerotolerant anaerobes
104
mcgs that are inhibited or even killed by O2
obligate anaerobes
105
Pasteurization; Careful control of flow rate and the size and temperature of the heat source raises the temperature of the milk to 71°C for 15 sec (or even higher temperatures for shorter time periods ), after which it is rapidly cooled. This process is called
flash pasteurization
106
Pasteurization; pasteurization of milk requires heat treatment at 135°C for 1–2 sec and actually sterilizes the milk such that it can be stored at room temperature for long periods without spoilage.
Ultrahigh-temperature (UHT) pasteurization
107
destroy all microorganisms, including endospores.
sterilants
108
are chemicals that kill microorganisms but not
necessarily endospores and are primarily used on surfaces.
disinfectants
109
less harsh than disinfectants and
reduce microbial numbers but do not sterilize.
sanitizers
110
a genetic element that can multiply only inside a living
cell, called the host cell.
virus
111
Viruses rely on the host cell for energy, metabolic intermediates, and protein synthesis, and so they are
obligate intracellular parasites
112
Although viruses are not cells, their genomes encode those functions needed to multiply and they have a structurally intricate
extracellular form, called the
virion
113
In enveloped viruses,
the inner structure of nucleic acid plus capsid protein is called the
nucleocapsid
114
Virions are composed of a protein shell, called the??? and the virus genome
capsid
115
The virus may replicate and destroy the
host in a virulent infection via a
lytic pathway
116
in this case, the host cell is not destroyed and the viral genome becomes part of the host genome.
lysogenic infection
117
are unusual animal viruses that convert their RNA genome to a DNA intermediate
retroviruses
118
A viral suspension can be quantified to estimate the number of infectious virions present per volume of fluid, a quantity called the
titer
119
in a plaque assay when a lytic virus infects host cells growing on a flat surface, a zone of cell lysis called a
plaque
120
some double-stranded DNA bacterial viruses, although capable of a virulent cycle,
can also infect their host and establish a long-term stable relationship. Such a virus is called a
temperate virus
121
bacterial viruses where once infection begins, it
proceeds to kill its host through lysis.
virulent virus
122
A cell that harbors a temperate virus
is therefore called a
Lysogen
123
During lysogeny, the temperate virus genome is often integrated into the bacterial chromosome. The viral DNA, now called a
prophage
124
functional unit of genetic information is the
gene
125
are single-stranded molecules
that carry the genetic information from DNA to the ribosome
Messenger RNAs (mRNAs)
126
help convert the genetic information in
the nucleotide sequences of RNA into a defined sequence of amino
acids in proteins.
Transfer RNAs (tRNAs)
127
are important catalytic
and structural components of the ribosome.
Ribosomal RNAs (rRNAs)
128
he main genetic element in prokaryotic cells is the
chromosome
129
are circular or linear double-stranded DNA molecules
that replicate separately from the chromosome and are typically
much smaller than chromosomes
plasmids
130
sequences of DNA that are inserted into other DNA molecules but
can move from one site on the DNA molecule to another, either
within the same molecule or on a different DNA molecule
transposable elements
131
Enzymes that catalyze the polymerization of deoxynucleotides are
called
DNA polymerases
132
Transcription is catalyzed by the enzyme
RNA polymerase
133
are large complexes of proteins and RNAs where the
cell’s proteins are biosynthesized
ribosomes
134
Bacteria produce a series of proteins that catalyze a variety of macromolecular folding events. These events include
folding proteins that do not fold spontaneously, refolding partially
denatured proteins, assembling multiprotein complexes, preventing the improper aggregation of proteins, untangling RNAs, and incorporating cofactors into enzymes.
chaperones
135
proteins that transport specific proteins into or through
the membranes of Bacteria and Archaea
translocases
136
unfolded proteins to be exported from the cytoplasm are recognized by either the SecA protein or the signal recognition particle (SRP)
sec system
137
Some proteins must be folded before they are translocated
because they contain cofactors that must be inserted as the protein folds; for example, iron–sulfur proteins, cytochromes, and other respiratory enzyme. Such proteins are processed by
the
“twin-arginine translocase" Tat translocase system
138
In order to insert proteins or other small molecules known as effectors into the outer membrane of
gram-negative Bacteria, or to secrete them outside of
the cell these are used
secretion systems
139
two-step translocases because they depend on either the Sec or Tat system
Type II and type V systems
140
systems found in a wide variety of gram-negative pathogenic and nonpathogenic bacteria, and they transport proteins from
the periplasm to the extracellular environment
Type II systems
141
structurally simplest of the secretion systems and are also called autotransporters in that the protein to be secreted is fused to a transmembrane protein domain essential to the protein’s transport across the outer membrane
Type V systems
142
one-step systems because they form channels through both the cytoplasmic and
outer membranes and do not require Sec or Tat
Types I, III, IV, and VI systems
143
are ABC transporters that are characterized by three
protein components:
(1) a cytoplasmic membrane transporter coupled to
(2) an outer membrane pore by (3) a membrane fusion
protein.
Type I systems
144
commonly used by pathogenic bacteria not only to secrete toxic proteins outside of the cell but to inject these molecules directly into eukaryotic host cells
Type III systems
145
the most ubiquitous and are
present in many Bacteria and Archaea. This system is also used to deliver secreted proteins or other molecules into other cells
Type IV systems
146
widely distributed in gram-negative bacteria,
and like type IV systems they are capable of delivering a diversity of
proteins directly into the cytoplasm of other cells using a one-step; I translocase is cytoplasmic and forms a needle-like protein with a pore-forming protein that contracts all the way through the donor cell’s two membranes and directly into
a host cell once a substrate molecule is recognized
Type VI systems
147
Proteins that control the rate of gene transcription by binding to
specific DNA sequences are called
tanscription factors
148
If binding to the DNA results in turning transcription on, the transcription factor is called an
activator protein
149
Conversely, binding of this protein to DNA results in turning gene expression off
repressor protein
150
Transcription factors are
???? proteins; that is, their conformation is altered when the
effector molecule binds to them; can either be inducer or corepressor
allosteric proteins
151
in Escherichia coli and many
other Bacteria, the enzymes needed to synthesize the amino acid arginine are made only when arginine is absent from
the culture medium; an excess of arginine decreases the synthesis of these enzymes. This is called
enzyme repression
152
an enzyme is made only when its substrate is present. usually affects the synthesis of specific degradative (catabolic) enzymes.
enzyme induction
153
lac operon; an isomer
made from lactose, is the actual inducer molecule that leads to the expression of the lac operon and ulltimately synthesis of the enzyme
b-galactosidase (encoded by lacZ).
allolactose
154
When more than one
operon is under the control of a single regulatory protein, these operons are collectively called a
regulon
155
Sensory proteins sense attractants or repellents
and interact with cytoplasmic sensor kinases. These sensory proteins are called
methyl-accepting chemotaxis proteins (MCPs)
156
sensor kinase for chemotaxis
ChaA
157
a central protein in the regulatory system because it governs
the direction of rotation of the flagellum
CheY
158
When MCPs bind a repellent or release an attractant, CheY is phosphorylated. CheY-P interacts with the flagellar motor to induce clockwise flagellar rotation, which causes
tumbling
159
When MCPs bind an attractant or release a repellent, CheY is unphosphorylated and cannot bind to the flagellar motor. This results in the flagellum rotating counterclockwise, causing the
cell to
run
160
Another protein dephosphorylates CheY, returning it to the form that allows runs instead of tumbles.
CheZ
161
an increase in repellent concentration leads to an increase in the level of CheY-P and therefore ????. By contrast, if the cell is swimming toward attractants, the ??? level of CheY-P suppresses
tumbles and promotes runs.
tumbling, lower
162
the chemotaxis protein that methylates MCPs
CheR
163
the protein that demethylates MCPs
CheB (Che B-P)
164
Candida, whose quorum sensing is mediated by the long-chain alcohol
farnesol
165
a mechanism of global control that controls the use of carbon sources
if more than one is present.
catabolite repression
166
If two usable energy sources are available, the cells first consume the better energy source. Growth stops when the better source is depleted, but following a lag period, it resumes on the other
energy source
diauxic growth
167
catabolite repression activator protein
cyclic AMP receptor protein (CRP)
167
CRP is an allosteric
protein and binds to DNA only if it has first bound a small
molecule called
cyclic adenosine monophosphate (cyclic AMP or cAMP)
168
Cyclic AMP is
synthesized from ATP by an enzyme called
adenylate cyclase
169
For lac genes to be transcribed, two requirements must
be met
(1) The level of cyclic AMP must be high enough for the CRP
protein to bind to the CRP-binding site (positive control), and
(2) lactose or another suitable inducer must be present so that the lactose repressor (LacI protein) does not block transcription by binding to the operator (negative control)
170
a widely distributed regulatory mechanism used by bacteria to survive nutrient deprivation, environmental stresses, and antibiotic exposure
stringent response
171
comprises over
400 genes including those associated with nutrient limitation, resistance to DNA damage, biofilm formation, and responses to osmotic, oxidative, and acid stresses. Thus, it not only senses environmental changes but also relays signals to other regulators.
RpoS regulon
172
The stringent response is triggered by a mixture of two regulatory nucleotides,
guanosine tetraphosphate (ppGpp)
guanosine pentaphosphate (pppGpp)
collectively, these are referred
to as (p)ppGpp
173
In Escherichia coli, these nucleotides rapidly accumulate during stress or a shift
down from amino acid excess to amino acid starvation. these
are synthesized by a specific protein, called RelA, using ATP as a phosphate donor
alarmones
174
consists of two-component regulatory system that responds to Pi limitation. This global control system includes not only genes encoding extracellular enzymes for extracting Pi from organic phosphates, but also genes encoding Pi transporters, enzymes for Pi storage, and other energy-requiring metabolic and biosynthesis
pathways as well.
phosphate (Pho) regulon
175
Because protein stability is critical for survival, cells employ a global control mechanism to protect cells from protein denaturation.
heat shock response
176
help counteract protein damage and assist the cell in recovering from stress due to heat stress and other conditions that
lead to protein unfolding
heat shock proteins
177
In most Bacteria and Archaea there are five major classes of heat shock protein:
Hsp100, Hsp90, Hsp70, Hsp60, and Hsp10
178
The Hsp70 protein of Escherichia coli is ???, which prevents aggregation of newly synthesized proteins and stabilizes unfolded proteins
DnaK
179
Major representatives of the Hsp60 and Hsp10 families in E. coli are the proteins
GroEL, GroES
180
Another group of heat shock proteins includes various proteases that degrade denatured or irreversibly aggregated proteins
Hsp100
181
controls expression of heat shock proteins and is normally degraded within a minute or two of its synthesis. However, when cells suffer a heat shock (or other stressor that leads to protein denaturation), its degradation inhibited and its level therefore increases.
RpoH
182
Catalytically active RNAs are called
ribozymes
183
Other RNA molecules which resemble repressors and activators in binding small metabolites and regulating gene expression
riboswitches
184
a form of transcriptional control in Bacteria and Archaea that functions by prematurely terminating mRNA synthesis. control is exerted after the initiation of transcription but before its completion
attenuation
185
A major means of controlling enzymatic activity; This mechanism temporarily shuts off the reactions in
an entire biosynthetic pathway.
feedback inhibition
186
a sigma factor widespread in
Bacteria that responds to extracytoplasmic stress by recognizing promoters for genes that encode products necessary for proper folding, expression, and turnover of proteins that reside in the outer membrane
RpoE
