micro exam 2 Flashcards
1
Q
microorganisms that are incubated in a closed culture vessel with a single batch of medium
A
batch culture
2
Q
when cells are sythesizing new components
A
lag phase
3
Q
microorganisms are growing and dividing at the maximal rate possible given their genetic potential, the nature of the medium, and the environemental conditions
A
exponential (log) phase
4
Q
all cellular constitutents are manufactured at constant rates relative to each other
A
balanced growth
5
Q
when nutrient levels or other environmental conditions change
A
unbalanced growth
6
Q
when a culture is transferred from a nutitionall poor medium to a richer one
A
shift up
7
Q
when a culture is transferred from a rich medium to a poor one
A
shift down
8
Q
in a closed system population growth eventually ceases and growth curve becomes horizontal
A
stationary phase
9
Q
reasons for entering stationary phase
A
- nutrient limitation
- oxygen availability
- accumulation of toxic wastes
- when a critical population level is reached
10
Q
protien directs the core enzyme to genes encoding protiens that will help the bacterium survive
A
RpoS protien
11
Q
proiens made in response to starvation
A
starvation protiens
12
Q
some cells are able to survive starvation for long periods of time
A
persister cells
13
Q
when cells are temporarily unable to grow at least under labratory conditions
A
viable but nonculturable cells
14
Q
cells genetically programmed to die after growth ceases
A
programmed cell death
15
Q
when a population doubles over a specific length of time
A
doubling or generation time
16
Q
the number of generations per unit time and is often expressed as generations per hour
A
mean growth rate (k)
17
Q
mean generation time
A
1/k
18
Q
literally counting number of microorganisms
A
hemacytometers
19
Q
practically better way of counting organisms , but wont tell you much about the organism, computer software can count for you
A
epifluorescent direct counts
20
Q
ways to measure biomass of microorganisms
A
- dry weight
- turbidimetry
- protien, ATP
- chlorophyll a
- ergosterol, hexosamine
21
Q
microorganisms that grow in harsh conditions
A
extremeophiles
22
Q
microbial growth has a characteristic temperature dependence
A
cardinal tempertures
23
Q
cardinal temperatures are made of
A
minimum
optimum
maximum
24
Q
the optimum is often found closer to the
A
maximum
25
chemicals that can be kept at high intracellular concentratoins without interfering wit hmetabolism and growth
compatible solutes
26
microbes adapted to extreme hypertonic environments
halophiles
27
the degree of water availability
a solution is 1/100 the relative humidity of the solution
equivalent to the ratio of the solution's vapor pressure to that of pure water
water activity (a_w)
28
microorganisms that grow over a wide range of water activity
osmotolerant
29
microorganisms with best growth at ph 0-5.5
acidophiles
30
microorganisms that grow best between pH 5.5-8.0
neurtophiles
31
microorganisms that grow best between pH 8.0-11.5
alkaliphiles
32
microorganisms that grow well at 0 C but grow best at 15 degrees C
psychrophiles
33
microorganisms that grow at 0 C but have an optimal growth around 35 degrees C
psychrotrophs
34
microorganisms that grow in moderate temperatures with an optima around 20-45 C
mesophiles
35
microorganisms that grow best at temperatures between 55-85 C
thermophiles
36
microorganisms with growth between 85-113 C
hyperthermophiles
37
organism able to grow in the presence of oxygen
aerobe
38
grows in the absence of oxygen
anaerobe
39
completely dependent on oxygen for growth
obligate aerobe
40
require oxygen levels around 2-10% of what is in the atmosphere for growth
microaerophiles
41
do not require oxygen for growth but do better in its presence
faculative anaerobes
42
grow equally well whether oxygen is present or not
aerotolerant anaerobes
43
killed in the presence of oxygen
obligate anerobes
44
toxic oxygen derivitives are called
reactive oxygen speceis (ROS)
45
Examples of ROS (3)
superoxide radical
hydrogen peroxide
hydroxyl radical
46
catalyse the destruction of superoxide radicals
superoxide dismutase
47
catalyse the destruction of hydrogen peroxide
catalase
48
increased pressure adversely affects them but not as much as it does nontolerant microbes
barotolerant
49
grow more rapidly at high pressures
piezphilic (barophilic)
50
radiation of very short wavelength and high energy which can cause atoms to lose electrons
ionizing radiation
51
two types of ionizing radiation
X rays and gamma rays
52
kill microorganisms due to its short wavelength (10-400 nm)
UV light
53
growth of microorganisms depends on
nutrient supply
| tolerance of the environmental conditions present in their habitat at any given time
54
complex, slime encased communities of microbes
biofilms
55
collection of polysaccarhides, protiens, glycoproteins, glycolipids, and DNA
extracellular polymeric substances (EPS)
56
allows microbes to stick more stably to surfaces
EPS matrix
57
two cells communicating with each other in a density dependent manner
quorum sensing
58
total of all chemical reactions happening in a cell
metabolism
59
conserve energy from organisms energy source, generate a ready supply of electrons and generate precursors for biosynthesis
catabolism
60
using products of the fueling reactions in another set of metabolic reactions that build new organic molecules from smaller inorganic and organic compounds
anabolism
61
synthesis of complex biological molecules from simpler precursors
chemical work
62
requires energy to take up nutrients , eliminate wates, and maintain ion balances
transport work
63
energy is required for cell motility and the movement of structures within cells, such as partitioning chromosomes during cell division
mechanical work
64
the capacity to do work
energy
65
analyzes energy changes in a collection of matter called a system
thermodynamics
66
first law of thermodynamics
matter can be neither created nor destroyed
67
measure of randomness of disorder in a system
entropy
68
second law of thermodynamics
physical and chemical processes proceed in such a way that the randomness or disorder of the universe increases
69
the amound of heat energy needed to raise 1 gram water from 14.5 to 15.5 celcius
calorie
70
units of work capable of being done
joules
71
change in heat content
enthalpy
72
amount of energy in a system available to do useful work at constant temperature and pressure
free energy change
73
spontaneous reactions have
negative delta G
74
when free energy change for a process is determined at carefully defined standard conditions of concentration, pressure, pH, and temperature
standard free energy change
75
ΔG° is negative and equilibrium constant is greater than one
exergonic reaction
76
ΔG° is posistive and equilibrium constant is less than one
endergonic reaction
77
most commonly used practical form of energy in a cell
ATP
78
reacions where electrons more from a donor to an acceptor
redox reactions
79
equilibrium constant for a redox reaction
standard reduction potential (Eo)
80
Measure of the tendency of the donor of a half reaction to lose electrons
standard reduction potential (Eo)
81
protiens that have FAD and FMN are
flavoprotiens
82
quinone that transports two electrons and two protons
coezyme Q or ubiquinone
83
use iron atoms to transport one electron at a time
cytochromes
84
iron containing electron carrying protiens that lack a heme group
nonheme iron protiens (iron sulfur protiens)
85
Fe-S protien active in photosyntheitic electron transport and several other electron transport processes
ferredoxin
86
protien catalysts that have great specificity for the reaction catalyzed, the molecules acted on, and the products they yield
enzymes
87
a substance that increases the rate of a chemical reaction without being permanetly altered itself
catalyst
88
reacting molecules enzymes work on
substrates
89
nonprotien component of an enzyme
cofactor
90
protien component of an enzyme
apoenzyme
91
complete enzyme composed of the apoenzyme and cofactor
holoenzyme
92
if the cofactor is firmly attached to the apoenzyme
prosthetic group
93
if the cofactor is loosely attached and can dissociate from the apoenzyme anfter products have formed
coenzyme
94
required to bring the reacting molecules together in the correct way to reach the transition state
activation energy
95
enzymes bring substrates together at a specific location in the enzyme to form an enzyme-substrate complex
active site or catalytic site
96
the active site is rigid and precisely shaped to fit the substrate so that a specific substrate binds and is positioned properly for the reaction
lock and key model
97
enzyme changes shape what it binds the substrate so that the active site surrounds and precisely fits the substrate
induced fit model
98
the substrate concentration required for the enzyme to achieve half-maximal velocity and used to measure the apparent affinity of an enzyme for its substrate
michaelis constant (Km)
99
when enzymes structure will be disrupted and its activity is lost
denaturation
100
directly competes with the substrate at an enzymes catalytic site and prevents the enzyme from forming product
competitive inhibitor
101
affect enzyme activity by binding to the enzyme at some location other than the active site
noncompetitive inhibitor
102
catalytic RNA molecules
ribozymes
103
metabolic pathways can be regulated in three major ways
1. metabolic channeling
2. regulation of the synthesis of a particular enzyme
3. direct stimulation or inhibition of the activity of critical enzymes
104
influences the pathway activity by localizing metabolites and nezymes to different parts of the cell
metabolic channeling
105
the differential distribution of enzymes and metabolites among separate cell structures or organelles
compartmentation
106
the direct stimulation or inhibition of the activity of critical enzymes rapidly alters pathway activity
pottranslational regulation
107
most regulatory enzymes are
allosteric enzymes
108
the activity of an allosteric enzyme is altered by a small molecule called
allosteric effector
109
the effector binds reversibly by noncovalent forces to an area separate from the catalytic site and causes a change in shape of the enzyme
regulatory site
110
regulatory enzymes also can be switched on and off by ____ which usually occurs through the addition and removal of a particular chemical group, typically a phosphate, methyl, or adenylyl group
reversible covalent modification
111
usually the first step in a pathway is a reaction catalyzed by a pacemaker enzyme. the end product of the pathway often inhibits this regulatory enzyme
feedback inhibition or end product inhibition
112
different forms of an enzyme that catalyze the same reaction
isoenzymes
113
when chemoorganotrophs oxidize an organic energy source, the electrons released are accepted by electron carriers. when these reduced electron carriers in turn donate the electrons to an electron transport chain, the process is called
respiration
114
uses an electron acceptor that is inside the cell and thus does not use an electron transport chain
fermentation
115
pathways with enzymes that function both catabolically and anabolically are
amphibolic pathways
116
a process that can completely catabolize an organic energy source to CO2 using the glycolic pathways and TCA cycle with O2 as the terminal electron acceptor for an electron transport chain
aerobic respiration
117
the metabolic pathways employed to catabolize glucose to pyruvate
glycolytic pathway or glycolysis
118
observed in almost all organisms and is the most common pathway for glucose degradation to pyruvate. it is an important amphibolic pathway and provides several precursor metabolites, NADH, and ATP for the cell. it occurs in the cytoplasm
embden-meyerhof pathway
119
ADP phosphorylation is coupled with the exergonic hydrolysis of high energy molecule having a higher phosphate trasfer potential than ATP
substrate-level phosphorylation
120
glycolysis pathway used by some soil bacteria and a few other gram negative bacteria
Entner-Doudoroff pathway
121
can be used at the same time as the Embden-Meyerhof or Entner-Doudoroff pathways. it can operate aerobically or anaerobically. Is important in biosynthesis and catabolism. used by all organisms because of its role in providing reducing power and important precusor molecules
pentose phosphate pathway or hexose monophosphate pathway
122
used to synthesize aromatic amino acids and vitamin B6 made from pentose phosphate pathway
erythrose 4-phosphate
123
major component of nucleic acids made from pentose phosphate pathway
ribose 5-phosphate
124
as pyruvate is oxidized one molecule of CO2 is produced along with this two carbon molecule
acetyl CoA
125
acetyl CoA molecule enters this cylce which furthur oxidizes the rest of the carbons of the original glucose molecule producing 2 CO2, 3 NADH, 1 FADH2, and 1 GTP per acetyl-CoA molecule
tricarboxylic acid cycle
kreb cycle
citric acid cycle
126
composed of a series of electron carriers that operate together to transfer electrons from donors such as NADH and FADH2 to O2
electron transport chain
127
process by which ATP is synthesized as the result of electron transport driven by the oxidation of a chemical energy source
oxidative phosphorylation
128
formulated by Peter Mitchell, stating ETC is organized so that protons move outward from the mitochondrial matrix as electrons are transported down the chain
chemiosmotic hypothesis
129
coenzyme Q accepts 2 electrons and 2 protons but delivers only the 2 electrons to complex III of the mitochondrial chain. this transfer of electrons is complicated by the fcact that cytochome b and the Fe-S protien of complex III accept only one electron at a time and do not accept proton. the difference in protons and electrons carried sets the stage for this phenomenon which ultimately moves 4 protons across the membrane
Q cycle
130
the combined chemical and electrical potential differences make up
proton motive force
131
roles of the proton motive force
1. phosphorylate ADP to ATP
2. transport molecules directly into the cell
3. rotat the bacterial flagellar motor
132
this multisubunit enzyme is part embeded in the plasma membrane or mitochondrial membrane and used to synthesize ATP
ATP F1F0 synthase
133
how many protons are used to produce ATP
4
134
how many protons does one NADH pump across the membrane
10
135
how many ATP molecules are produces per one NADH molecule
2.5
136
how manyk protons are pumped across by FADH2
6
137
how many ATP molecules are produced per one FADH2 molecule
1.5
138
during aerobic respiration of glucose, at most how many ATP molecules are generated by substrate phosphoylation
4
139
maximum yeild of ATP from oxidative phosphorylaltion
28
140
maximum amount of ATP produced during aerobic respiration is
32
141
two other factors that affect the theoretical yeild of ATP produced by bacterial and arcaeal cells
1. the PMF generated is used for work other than the generation of ATP
2. the amphibolic nature of the pathways used to catabolize glucose
142
the process whereby an exogenous terminal electron acceptor other than O2 is used for electron transport
anaerobic respiration
143
anaerobic reduction of nitrate makes it unavaliable for assimilation into the cell
dissimilatory nitrate reduction
144
use the Embden-Meyerhof pathway and directly reduce almost all their pyruvate to lactate wit the enzyme lactate dehydrogenase
homolactic fermenters
145
form substantial amounts of products aother than lactate, many also produce ethanol and carbon dioxide
heterolactic fermenters
146
microbes ferment surgars to ethanol and carbon dioxide
alcoholic fermentation
147
results in the excretion of theanol and a mixture of acids, particularly acetic, lactic, succinic, and formic acids
mixed acid fermentation
148
complex fermentaion resulting in the creation of butanediol
butanediol fermentation
149
donate electrons to their ETCs by oxidizing inorganic molecules rather than organic nutrients
chemolithotrophs
150
bacteria that are able to carry out nitrification
nitrifying bacteria
151
the oxidation of ammonia to nitrate
nitrification
152
electrons derived from the oxidation of inorganic substrates are moved up the ETC to reduce NADP to NADPH
reverse electron flow
153
all DNA present in a cell or virus
genome
154
the specific set of genes an oragnisms posesses
genotype
155
the collection of characteristics that are observable
phenotype
156
which molecule was believed to house the genetic information before DNA
protiens
157
worked with streptococcus pneumoniea and set the stage for research showing that DNA was indeed the genetic material
fred griffith
158
scientists who provided evidence that griffiths transforming principle was DNA and therefor that DNA carried genetic material
Avery, MacLeod, and McCarthy
159
scientists that used radioactive sulfur and phosphorus to show that DNA was exchanging genetic material from viruses
Hershey and Chase
160
synthesis of duplicate DNA is directed by both strands of the parental molcule
replication
161
genetic information is divided into units called
genes
162
synthesis of an RNA copy of a gene
transcription
163
transcription yeild three types of RNA
messenger RNA
transfer RNA
ribosomal RNA
164
genetic information in the form of an RNA bse sequence in a messenger RNA is decoded and used to govern the synthesis of a polypeptide
translation
165
contains bases adenine, guanine, cytosine, and thymine
deoxyribonucleic acid
166
purines
adenine and guanine
167
pyrimidines
thymine and cytosine
168
the bases in one strand match up with those of the other according to specific base pairing rules
complementary
169
contains bases adenine, guanine, cytosine, and uracil
ribonucleic acid
170
what are the basic building blcoks of protiens
amino acids
171
defined by the presence of a central carbon to which is attached a carboxyl group and amino group and a side chain
amino acid
