Practice Exam Flashcards
(150 cards)
0
Q
T/F all bacteria double their numbers every 20 minutes.
A
False
1
Q
Most bacteria increase in number through the process of
A
Binary fission
2
Q
When comparing direct microscopic counts of microbial growth to plate counts, plate counts _______ tell you whether the cells are dead or alive
A
Will
3
Q
Microbes will not be able to grow below their minimal temperatures because
A
Proteins denature
4
Q
A pastry chef with poor personal hygiene inadvertently inoculate a crime puff with 100 Staphylococcus aureus cells. The crime puff sat on the bakery display shelf for four hours and was purchased and consumed by a college student on her way home from micro class. S. Aureus has a generation time of 20 minutes, approximately how many bacteria did the student eat?
A
409,600
5
Q
Salts preserve foods by creating a(n) ______ relative to the inside of the cell
A
Hypertonic environment
6
Q
As potential pathogens and the fact that they are growing on nutrient agar plates the organisms are most likely
A
Chemoorganoheterotrophs
11
Q
which of the four microbial growth controls is/are physical methods to kill microbes
A
sterilization (ex. autoclave, gamma radiation)
12
Q
which of the four microbial growth controls are chemical methods to kill microbes?
A
antiseptic
disinfectant
sanitize
13
Q
physical and chemical methods are both _________ methods to kill microbes
A
nonspecific methods
14
Q
how are antibiotics different from all of the methods to control microbial growth discussed this far?
A
antibiotics are specific and target a certain microbe (targeted towards pathogens - towards Bacteria)
15
Q
bactericidal
A
kills bacteria
16
Q
bacteriostatic
A
inhibits growth
17
Q
Is penicillin considered bactericidal or bacteriostatic?
A
bactericidal - directly leading to death of organism (it prevents proper cell wall division)
18
Q
which environment is most harmful to a bacterial cell?
A
hypertonic
19
Q
plasmolysis can occur when a bacterial cell is placed into a ________ solution
A
hypertonic
20
Q
the test tube of media shown (lots of growth on top and little distributed throughout tube) is likely to have which kind of organism in it?
A
facultative anaerobe
21
Q
an obligate anaerobe will produce which enzyme?
A
neither catalase nor SOD
22
Q
organisms that can tolerate environments with high salt concentrations, such as your skin, are ___________
A
halotolerant
23
Q
write out the timeline of how antibiotic resistance developed
A
- penicillin was discovered
- more antibiotics discovered
- penicillin used (used widely in WW II) –> rapid decline in infections
- “magic bullet” - widespread use (decrease in research)
- antibiotic resistance started growing rapidly (where we are today)
24
Q
plasmolysis
A
plasma membrane shrinks away from cell wall in hypertonic solution
- supposed to be close together (will screw up metabolism)
25
Q
facultative anaerobe
A
has a preference to grow with oxygen because it is more endogenically favorable (more growth near top of culture)
26
Q
what percent of salt can halophiles live in
A
1-15%
27
Q
penicillin inhibits __________
A
peptidoglycan synthesis
28
cells divide at their maximal rates during ___________
log phase
29
what happens to cells at high temperatures?
cytoplasmic membrane collapses
nucleic acids denature
proteins denature
30
which of the following is false about the enzymes of acidophiles?
they have an activity optimum at pH below neutral
they will be denatured at high pH
they are found in soda lakes
they are found in low pH bogs
they are found in soda lakes
31
potato salad at a restaurant salad bar was inadvertently inoculated with 1 Salmonella cell. The potato salad sat at room temperature for 2 hours. Assuming that Salmonella has a generation time of 10 minutes, approximately how many bacteria were present after 2 hours?
4,096
32
when a halophile is placed in distilled water the cell is placed in a(n)
hypotonic environment
33
high temperatures are more lethal to cells than low temperatures. This is because
heat damage tends to be irreversible
34
the average temperature of the oceans is 5 degrees C. You would then predict that the majority of marine microorganisms would be
psychrophiles
35
why is molecular oxygen (O2) a toxic molecule for cells
free radicals produced during O2 reduction pull electrons off cellular components
36
what is the difference between an antiseptic and a disinfectant
disinfectants kill pathogens on inanimate surfaces, antiseptics kill pathogens on living tissues
37
what is the desired result of the quadrant streak plate technique
obtain will isolated bacterial colonies
38
what do we call an organism that grows best in the presence of low amounts of oxygen?
microaerophile
39
Bacillus cereus can grow in cooked rice while it is cooling in a refrigerator (from 45 C to 15 C), but not once it cools below 15C. Therefore B. cereus is a(n)
mesophile
40
which of the following statements about metabolism in prokaryotes is false?
a. anabolic reactions transfer energy to ATP
b. ATP is the link between anabolic and catabolic reactions
c. degradation reactions release energy
d. synthesis reactions use energy
A
41
the substrate in a reaction contacts a specific region of the enzyme molecule called the _______
active site
42
synthesis reactions ______ energy
use
43
degradation reactions ______ energy
release
44
ATP is the link between _______ and catabolic reactions
anabolic
45
what is a cofactor
the non-protein component of an enzyme
46
how many net ATP are produced from fermentation of glucose with ethanol as the fermentation end product
2
47
how many net ATP are produced from the fermentation of glucose with lactic acid as the fermentation end product?
2
48
Desulfovibrio use SO4 (sulfate) as a terminal electron acceptor, reducing it to H2S (hydrogen sulfide). These bacteria are _______
anaerobic respiring prokaryotes
49
which group of organisms would use oxygen as a terminal electron acceptor and utilize an electron transport chain
aerobic respirers
50
fertilizer is typically applied as NO3-, which of the following processes results in the conversion of NO3- to N gas
denitrification
51
the energy generated by catabolic pathways is used
to make cellular components
for motility
to transport substances across the cytoplasmic membrane
52
uses glucose for carbon and energy
chemoorganoheterotroph
53
uses CO2 for carbon and H2 for energy
chemolithoautotroph
54
which of the following is the best definition of fermentation
oxidation of glucose with an internal organic molecule serving as the electron acceptor
55
which of the following is the best definition of glycolysis
oxidation of glucose to pyruvate
56
which of the following is not necessary for respiration
oxygen
57
a strictly fermentative organism produces energy
by glycolysis only
58
which of the following is not an end-product of fermentation
a. lactic acid b. pyruvate
c. ethanol d. CO2
pyruvate
62
sterilization
destroys all viable cells, spores, and viruses
63
antiseptic
kill pathogens on living tissue
64
sanitize
lowers number of pathogens on a surface to an acceptable level
65
disinfectant
kill pathogens on inanimate objects
66
define oxidation-reduction
a coupled reaction in which one substance loses electrons and another gains electrons
67
define aerobic respiration
the final electron acceptor is molecular oxygen
68
define anaerobic respiration
the final electron acceptor is another inorganic molecule
69
define respiration
an ETC is used , the final electron acceptor is usually inorganic
70
define fermentation
an ETC is not used
| the final electron acceptor is usually organic
71
define cyclic photphosphorylation
electrons are returned to chlorophyll
72
define noncyclic photophosphorylation
chlorophyll receives electrons from hydrogen atoms
73
why must NADH be reoxidized
NAD+ is needed to pick up more electrons
74
How does this happen in an organism that uses repiration? Fermentation? (Why must NADH be reoxidized)
NADH is usually reoxidized in respiration
| NADH can be reoxidized in fermentation
75
which reaction produces the most molecules of ATP during aerobic metabolism?
acetyl CoA --> CO2 + H2O
76
which of the following compounds has the greatest amount of energy for a cell?
glucose
77
which of the following is the best definition of the Krebs cycle?
a series of chemical reactions in which NADH is produced from the oxidation of pyruvic acid
78
which of the following is the best definition of respiration?
a sequence of carrier molecules with an inorganic molecule as the final electron acceptor
79
which culture produces the most lactic acid?
E. coli growing in glucose broth at 35 C without O2 for 5 days
80
which culture produces the most ATP
E. coli growing in glucose broth at 35 C with O2 for 5 days
81
which culture uses NAD+?
E. coli growing in glucose broth at 35 C with and without O2 for five days
82
describe binary fission
the cell elongates, and the chromosome replicates. Next the nuclear material is evenly divided. The plasma membrane invaginates toward the center of the cell. The cell wall thickens and grows inward between the membrane invaginations; two new cells result
83
macronutrients are often listed as CHNOPS. What does each of these letters indicate, and why are they needed by the cell?
C: carbon - synthesis of molecules that make up a living cell
H: hydrogen - source of electrons and component of organic molecules
N: nitrogen - component of amino acids
O: oxygen - component of organic molecules
P: phosphorous - in phosolipids and nucleic acids
S: sulfur - in some amino acids
84
seven methods of measuring microbial growth are explained in this chapter (6). Categorize each as either a direct or an indirect method.
direct methods are those in which the microorganisms are seen and counted. Direct methods are direct microscope count, plate count, filtration, and most probable number.
85
by deep-freezing, bacteria can be stored without harm for extended periods. Why do refrigeration and freezing preserve foods?
the growth rate of bacteria slows down with decreasing temperatures. Mesophilic bacteria will grow slowly at refrigeration temps and will remain domain in a freezer. Bacteria will not spoil food quickly in a refrigerator
86
nitrogen and phosphorous added to beaches following an oil spill encourage the growth of natural oil-degrading bacteria. Explain why the bacteria do not grow if nitrogen and phosphorous are not added.
petroleum can meet the carbon and energy requirements for an oil-degrading bacterium however nitrogen and phosphate are usually not available in large quantities. Nitrogen and phosphorous are essential for making proteins, phospholipids, nucleic acids, and ATP
87
differentiate complex and chemically defined media
a chemically defined medium is one in which the exact chemical composition is known
a complex medium is one in which the exact chemical composition is not known
88
the term trace elements refers to
small mineral requirements
89
which one of the following temperatures would most likely kill a mesophile
60 C
90
which of the following types of media would not be used to culture aerobes
a. selective
b. reducing
c. enrichment
d. differential
e. complex
reducing media
91
an organism that has peroxidase and superoxide dismutase but lacks catalase is most likely an
aerotolerant anaerobe
92
catabolism
chemical reactions that result in the breakdown of more complex organic molecules into simpler substances
93
catabolic reactions ________ energy
release
94
anabolism
chemical reactions in which similar substances are combined to form more complex molecules
95
anabolic reactions__________ energy
use
96
the energy of catabolic reactions is used to drive _______ reactions
anabolic
97
the energy for chemical reactions is stored in _______
ATP
98
enzymes are generally _____ proteins
globular
99
most enzymes are __________, consisting of a protein portion and a nonprotein portion
holoenzymes
100
protein portion
apoenzyme
101
nonprotein portion
cofactor
102
at high temperatures, enzymes undergo ________ and lose their catalytic properties
denaturation
103
optimum pH
the pH at which enzymatic activity is maximal
104
enzymatic activity increases as substrate concentration _______ until the enzymes are saturated
increases
105
oxidation
the removal of one or more electrons from a substrate
protons (H+) are often removed with the electrons
106
reduction
gain of one or more electrons
107
NAD+ is the _______ form
oxidized
108
NADH is the ________ form
reduced
109
glucose is a ______ molecule
reduced
110
addition of a Pi to a molecule is called ________
phosphorylation
111
most of a cell's energy is produced from the ________ of carbohydrates
oxidation
112
________ is the most commonly used carbohydrate
glucose
113
the two major types of glucose catabolism are _______ and fermentation
respiration
114
respiration
glucose is completely broken down
115
fermentation
glucose is partially broken down
116
the most common pathway for the oxidation of glucose is _______
glycolysis
117
______ is the end-product of glycolysis
pyruvic
118
_____ ATP and 2 NADH molecules are produced from one glucose molecule
2
119
during respiration, ________ are oxidized
organic molecules
120
in aerobic respiration, _____ functions as the final electron acceptor
O2
121
in anaerobic respiration, the final electron acceptor is usually an _______ molecule other than O2
inorganic molecule
122
fermentation ______ energy from sugars or other organic molecules by ________
releases
| oxidation
123
______ is not required in fermentation
O2
124
electrons removed from the substrate _______ NAD+ (fermentation)
reduce
125
fermentation: the final electron acceptor is an ________ molecule
organic
126
in lactic acid fermentation, ________ is reduced by NADH to lactic acid
pyruvic acid
127
_______ hydrolyze lipids into glycerol and fatty acids
lipases
128
fatty acids and other hydrocarbons are catabolized by ________
oxidation
129
catabolic products can be further broken down in glycolysis and ________
Krebs cycle
130
photosynthesis
the conversion of light energy from the sun into chemical energy; the chemical energy is used for carbon fixation
131
in cyclic phosphorylation, the electrons return to the ________
chlorophyll
132
in oxidation-reduction reactions, energy is derived from the _______ of electrons
transfer
133
to produce energy, a cell needs an _________
electron donor, a system of electron carriers, and a final electron acceptor
134
photoautotrophs
obtain energy by phosphorylation and fix carbon from CO2 via the Calvin-Benson cycle to synthesize organic compounds
135
cyanobacteria are oxygenic _________
phototrophs
136
Green bacteria and purple bacteria are anoxygenic _______
phototrophs
137
_____________ use inorganic compounds as their energy source and carbon dioxide as their carbon source
chemoautotrophs
138
__________ use complex organic molecules as their carbon and energy sources
chemoheterotrophs
139
amino acids are required for _______
protein biosynthesis
140
psychrophiles
cold-loving
141
mesophiles
moderate-temperature-loving
142
thermophiles
heat-loving
143
optimum growth
temperature at which it grows best
144
minimum growth temperature
the lowest temperature at which a species will grow
145
maximum growth temperature
highest temperature at which growth is possible
146
most bacteria grow best at a pH value between _____ and ____
6.5-7.5
147
in a ________ solution, most microbes undergo plasmolysis
hypertonic
148
________ can tolerate high salt concentrations
halophiles
149
_________ use an organic molecule as their carbon source
chemoheterotrophs
150
________ typically use carbon dioxide as their carbon source
autotrophs
151
microbes in biofilms are more resistant to ______ than are free-swimming microbes
antibiotics
152
generation time
the time required for a cell to divide or a population to double
153
bacterial division occurs according to a ______ progression
logarithmic
154
during the _______ phase, there is little or no change in the number of cells, but metabolic activity is high
lag
155
during the ______ phase, the bacteria multiply at the fastest rate possible under the conditions provided
log
156
during the _______ phase, there is an equilibrium between cell division and death
stationary
