Transcript The Biotechnology Century and Its Workforce

Active Lecture
Questions
Chapter 7
The Control of
Microbial Growth
Copyright © 2010 Pearson Education, Inc.
Which of the following does not kill
endospores?
a.
b.
c.
d.
e.
autoclaving
incineration
hot-air sterilization
pasteurization
All of the above kill endospores.
Which of the following is most effective
for sterilizing mattresses and plastic Petri
dishes?
a.
b.
c.
d.
e.
chlorine
ethylene oxide
glutaraldehyde
autoclaving
nonionizing radiation
Which of these disinfectants does not act
by disrupting the plasma membrane?
a.
b.
c.
d.
e.
phenolics
phenol
quaternary ammonium compounds
halogens
biguanides
Which of the following cannot be used to
sterilize a heat-labile solution stored in a
plastic container?
a.
b.
c.
d.
e.
gamma radiation
ethylene oxide
nonionizing radiation
autoclaving
short-wavelength radiation
Which of the following is not a
characteristic of quaternary ammonium
compounds?
a.
b.
c.
d.
e.
bactericidal against gram-positive bacteria
sporicidal
amoebicidal
fungicidal
kills enveloped viruses
A classmate is trying to determine how a
disinfectant might kill cells. You observed that
when he spilled the disinfectant in your
reduced litmus milk, the litmus turned blue
again. You suggest to your classmate that
a.
b.
c.
d.
e.
the disinfectant might inhibit cell wall synthesis.
the disinfectant might oxidize molecules.
the disinfectant might inhibit protein synthesis.
the disinfectant might denature proteins.
he take his work away from yours.
Which of the following is most likely to be
bactericidal?
a.
b.
c.
d.
e.
membrane filtration
ionizing radiation
lyophilization (freeze-drying)
deep-freezing
all of the above
Which of the following is used to control
microbial growth in foods?
a.
b.
c.
d.
e.
organic acids
alcohols
aldehydes
heavy metals
all of the above
The data were obtained from a use-dilution
test comparing four disinfectants against
Salmonella choleraesuis. G = growth, NG = no
growth.
Which disinfectant is the most effective?
a.
b.
c.
d.
e.
A, B, C, and D
A, C, and D
A only
B only
none of the above
Which disinfectant(s) is (are)
bactericidal?
a.
b.
c.
d.
e.
A, B, C, and D
A, C, and D
A only
B only
none of the above
The removal or destruction of all forms of
microbial life is called
a.
b.
c.
d.
Sterilization
Disinfection
Pasteurization
Sanitization
Treatment intended to lower microbial
counts on eating and drinking utensils to
safe public health levels:
a.
b.
c.
d.
Sanitization
Sterilization
Pasteurization
Antisepsis
Commercial sterilization is a limited heat
treatment to destroy
a.
b.
c.
d.
Streptococcus pyogenes
Clostridium tetani
Staphylococcus aureus
Clostridium botulinum endospores
Which of the following BEST describes
the pattern of microbial death?
a. The cells in a population die at a constant
rate
b. All the cells in a culture die at once
c. Not all of the cells in a culture are killed
d. The pattern varies, depending on the species
The lowest temperature at which all of
the microorganisms in a particular liquid
suspension will be killed in 10 minutes is
called
a.
b.
c.
d.
Thermal death point
Thermal death time
Decimal reduction time
Decimal reduction point
Which one of the following is the BEST
advertisement for a disinfectant?
a.
b.
c.
d.
Kills E. coli
Kills Staphylococcus aureus
Kills Pseudomonas
Kills lipophilic viruses
To sterilize heat-labile solutions, one
should use
a.
b.
c.
d.
Dry heat
Autoclave
Membrane filtration
Pasteurization
The phosphatase test is used to
determine whether which one of the
following processes was carried out
correctly?
a.
b.
c.
d.
Radiation
Filtration
Desiccation
Pasteurization
Which of the following methods causes
destruction of DNA?
a.
b.
c.
d.
Radiation
Osmotic pressure
Heat
Desiccation
Sterilization can be achieved by using
a.
b.
c.
d.
Alcohol
Soap
Chlorine
Ethylene oxide
The eradication of nonenveloped viruses
CANNOT be achieved by
a.
b.
c.
d.
Chlorine
Ozone
Alcohol
Ethylene oxide
Which of the following is NOT used to
preserve foods?
a.
b.
c.
d.
Nisin
Sodium nitrite
Potassium sorbate
Biguanides
Which of the following is the MOST
useful for disinfecting medical
instruments?
a.
b.
c.
d.
Quats
Chlorine
Phenol
Benzoic acid
These chemical agents cause a
disruption of the plasma membrane and
denaturation of enzymes:
a.
b.
c.
d.
Phenolics
Biguanides
Alcohols
Halogens
What chemical is used to prevent molds
from growing in cheese and soft drinks?
a.
b.
c.
d.
Sorbic acid
Calcium propionate
Sulfur dioxide
Sodium nitrate