MICR 351 Final Exam Questions and
Answers
The lipopolysaccharide (LPS) that is found in the outer membrane of gram-negative bacteria is also
known as: - Answer-Endotoxin
T or F: Generally, bacterial mitochondria are much smaller than a mitochondria of eukaryotic cells -
Answer-False
A(n) ________ is the total number of cases of a disease at any one time in a population - Answer-
Prevalence
Which of the following are characteristics used in taxonomic organization?
a) Morphological
b) Physiological
c) Ecological
d) Two of the above
e) All of the above - Answer-e) All of the above
Proteins that are loosely attached to the cytoplasmic membrane are called ____ proteins - Answer-
Peripheral
,An epidemic is: - Answer-A sudden increase in the occurrence of a disease above the expected level
Which of the following is NOT a criterion for the classical postulate of Robert Koch?
a) Microbes must be present in every case of disease and absent from healthy individuals
b) Must be able to grow the microbes in pure culture
c) Cultured microbes must give the same disease state
d) Must be able to identify the virulence gene(s) responsible for the disease - Answer-d) Must be able to
identify the virulence gene(s) responsible for the disease
Aerobic cells may enter stationary phase because: - Answer-- Depletion of an essential nutrient
- The accumulation of toxic waste products
T or F: In a normal situation, the bacterium E. coli swims in a straight line, called a run, for a few
seconds; then it stops, tumbles, then swims again in a new direction - Answer-True
Chemotaxis implies that bacteria: - Answer-Move toward an attractant and away from a repellent
The movement of molecules across a membrane from an area of higher concentration to an area of
lower concentration with the use of a carrier molecule embedded in the membrane is called: - Answer-
Facilitated diffusion
Environmental factors affecting growth of strict anaerobic bacteria can include but are not limited to
which of the following:
a) pH
b) Oxygen
c) Temperature
, d) Two of the above
e) All of the above - Answer-e) All of the above
If you had a tube filled with a solid media and after inoculation you observe uniform growth throughout
the tube, they you most likely have a(n): - Answer-Aerotolerant anaerobe
Given a log phase bacterial culture with 10e6 cells per mL and a generation time of 30 minutes, how
long does it take the culture to reach a density of 6.4x10e7 cells per mL? - Answer-3 hours
Microorganisms generally maintain the fluidity of the mosaic membrane by:
a) Increasing the level of cis unsaturated fatty acid in the membrane at low temperature
b) Increasing the level of saturated fatty acid in the membrane at high temperature
c) Increasing the number of fatty acid molecules on the phospholipid at high temperature
d) Two of the above
e) All of the above - Answer-d) Two of the above
You find that a microorganism has optimum growth at pH 9.5 and a temperature of 10C, this organism is
a: - Answer-Alkalophilic psychrophile
Nutrients can be concentrated inside the cell from a diluted extracellular environment by: - Answer-
Active transport and group translocation
E. coli doubles every 20 minutes at optimal growth. Within the first 5 minutes after you add 10
micrometers of a dense E. coli culture grown in minimal media into a flask containing 100 mL of a rich
media, you can assume these bacteria are in: - Answer-Death phase
You want to measure the O.D. (optical density) of a dense E. coli culture grown overnight using a
spectrophotometer to estimate cell numbers. You can expect to see: - Answer-- Low transmittance
Answers
The lipopolysaccharide (LPS) that is found in the outer membrane of gram-negative bacteria is also
known as: - Answer-Endotoxin
T or F: Generally, bacterial mitochondria are much smaller than a mitochondria of eukaryotic cells -
Answer-False
A(n) ________ is the total number of cases of a disease at any one time in a population - Answer-
Prevalence
Which of the following are characteristics used in taxonomic organization?
a) Morphological
b) Physiological
c) Ecological
d) Two of the above
e) All of the above - Answer-e) All of the above
Proteins that are loosely attached to the cytoplasmic membrane are called ____ proteins - Answer-
Peripheral
,An epidemic is: - Answer-A sudden increase in the occurrence of a disease above the expected level
Which of the following is NOT a criterion for the classical postulate of Robert Koch?
a) Microbes must be present in every case of disease and absent from healthy individuals
b) Must be able to grow the microbes in pure culture
c) Cultured microbes must give the same disease state
d) Must be able to identify the virulence gene(s) responsible for the disease - Answer-d) Must be able to
identify the virulence gene(s) responsible for the disease
Aerobic cells may enter stationary phase because: - Answer-- Depletion of an essential nutrient
- The accumulation of toxic waste products
T or F: In a normal situation, the bacterium E. coli swims in a straight line, called a run, for a few
seconds; then it stops, tumbles, then swims again in a new direction - Answer-True
Chemotaxis implies that bacteria: - Answer-Move toward an attractant and away from a repellent
The movement of molecules across a membrane from an area of higher concentration to an area of
lower concentration with the use of a carrier molecule embedded in the membrane is called: - Answer-
Facilitated diffusion
Environmental factors affecting growth of strict anaerobic bacteria can include but are not limited to
which of the following:
a) pH
b) Oxygen
c) Temperature
, d) Two of the above
e) All of the above - Answer-e) All of the above
If you had a tube filled with a solid media and after inoculation you observe uniform growth throughout
the tube, they you most likely have a(n): - Answer-Aerotolerant anaerobe
Given a log phase bacterial culture with 10e6 cells per mL and a generation time of 30 minutes, how
long does it take the culture to reach a density of 6.4x10e7 cells per mL? - Answer-3 hours
Microorganisms generally maintain the fluidity of the mosaic membrane by:
a) Increasing the level of cis unsaturated fatty acid in the membrane at low temperature
b) Increasing the level of saturated fatty acid in the membrane at high temperature
c) Increasing the number of fatty acid molecules on the phospholipid at high temperature
d) Two of the above
e) All of the above - Answer-d) Two of the above
You find that a microorganism has optimum growth at pH 9.5 and a temperature of 10C, this organism is
a: - Answer-Alkalophilic psychrophile
Nutrients can be concentrated inside the cell from a diluted extracellular environment by: - Answer-
Active transport and group translocation
E. coli doubles every 20 minutes at optimal growth. Within the first 5 minutes after you add 10
micrometers of a dense E. coli culture grown in minimal media into a flask containing 100 mL of a rich
media, you can assume these bacteria are in: - Answer-Death phase
You want to measure the O.D. (optical density) of a dense E. coli culture grown overnight using a
spectrophotometer to estimate cell numbers. You can expect to see: - Answer-- Low transmittance
