MCB 100 FINAL CLICKER- QUESTIONS AND
ACCURATE ANSWERS
When microbial control methods are used, microbes are destroyed at a constant rate;
there is no instantaneous death of all the microbes present. This microbial death rate is
influenced by all of the following factors, except
A. the microbial physiological characteristics.
B. the number of microbes that are present.
C. the length of time of exposure to the treatment.
D. the stability of the proteins in the bacteria.
E. the toxins and metabolites produced by the bacteria. - Answers - the toxins and
metabolites produced by the bacteria
Factors include: stability of proteins in bacteria, # of microbes present, length of time of
exposure, microbial physiological characteristics
Determine which of the following statements is true or false and then select the correct
answer sequence:
- The term antimicrobial agent includes antibiotics, fungicidal and antiparasitic agents.
- Bacteriostatic agents inhibit bacterial growth, but do not necessarily kill the organisms
against which they are directed.
- Agents that inhibit bacterial cell wall biosynthesis can be bactericidal.
- Antiseptics are sufficiently nontoxic that they can be applied to skin.
A. false, true, true, true
B. true, true, true, false
C. true, true, false, true
D.false, false, false, false
E. true, true, true, true - Answers - T,T,T,T
Antimicrobial agents: antibiotics, funficidal, and anti-parasitic agents
bacteriostatic= inhibit growth
bactercidial= kill bacteria
bactericidal agents= inhibit cell wall
body surfaces= antiispetics, germicides
inanimate objects= disinfectants, sanitizers
, safe to ingest/inject= antibiotics, antimicrobials
Moist heat kills microbes faster than dry heat because _____
A. water has a higher heat capacity than air, which means it takes more energy to raise
the temperature of water.
B. hot water makes the cells swell and burst, while hot air just shrinks the cells.
C. hot air removes the water from the cells but does not kill them right away.
D. hot air causes the cells to release water which evaporates and cools them off and
keeps them alive longer.
E. moist heat kills microbes by denaturing protein and nucleic acid structures and
disrupting cell membranes, which takes less time to kill cells than removing water by dry
heat and killing cells through oxidation reactions. - Answers - moist heat kills microbes
by denaturing protein and nucleic acid structures and disrupting cell membranes, which
takes less time to kill cells than removing water by dry heat and killing cells through
oxidation reactions.
Which of the following statements about pasteurization is not true?
A. Pasteurization reduces the microbial load in heat-sensitive liquids.
B. Pasteurization controls microbes that cause spoilage, such as E. coli and
Salmonella.
C. Pasteurization increases the shelf life of perishable liquids.
D. Pasteurization involves flash heating to 135°C for about a minute.
E. Pasteurization is a method of sterilization that kills microbes present in food. -
Answers - Pasteurization is a method sterilization that kill microbes present in food
(does not completely kill but reduces)
An autoclave is able to achieve temperatures higher than that of boiling water
____________
A. by decreasing the volume of liquid.
B. by increasing the temperature higher than boiling water.
C. by increasing the time of exposure to boiling water.
D. Actually, autoclaves cannot reach temperatures higher than boiling water.
E. by increasing the pressure. - Answers - e) increasing the pressure
Oxidizing agents such as chlorine or hydrogen peroxide are particularly effective against
_________ organisms.
A. microaerophilic
ACCURATE ANSWERS
When microbial control methods are used, microbes are destroyed at a constant rate;
there is no instantaneous death of all the microbes present. This microbial death rate is
influenced by all of the following factors, except
A. the microbial physiological characteristics.
B. the number of microbes that are present.
C. the length of time of exposure to the treatment.
D. the stability of the proteins in the bacteria.
E. the toxins and metabolites produced by the bacteria. - Answers - the toxins and
metabolites produced by the bacteria
Factors include: stability of proteins in bacteria, # of microbes present, length of time of
exposure, microbial physiological characteristics
Determine which of the following statements is true or false and then select the correct
answer sequence:
- The term antimicrobial agent includes antibiotics, fungicidal and antiparasitic agents.
- Bacteriostatic agents inhibit bacterial growth, but do not necessarily kill the organisms
against which they are directed.
- Agents that inhibit bacterial cell wall biosynthesis can be bactericidal.
- Antiseptics are sufficiently nontoxic that they can be applied to skin.
A. false, true, true, true
B. true, true, true, false
C. true, true, false, true
D.false, false, false, false
E. true, true, true, true - Answers - T,T,T,T
Antimicrobial agents: antibiotics, funficidal, and anti-parasitic agents
bacteriostatic= inhibit growth
bactercidial= kill bacteria
bactericidal agents= inhibit cell wall
body surfaces= antiispetics, germicides
inanimate objects= disinfectants, sanitizers
, safe to ingest/inject= antibiotics, antimicrobials
Moist heat kills microbes faster than dry heat because _____
A. water has a higher heat capacity than air, which means it takes more energy to raise
the temperature of water.
B. hot water makes the cells swell and burst, while hot air just shrinks the cells.
C. hot air removes the water from the cells but does not kill them right away.
D. hot air causes the cells to release water which evaporates and cools them off and
keeps them alive longer.
E. moist heat kills microbes by denaturing protein and nucleic acid structures and
disrupting cell membranes, which takes less time to kill cells than removing water by dry
heat and killing cells through oxidation reactions. - Answers - moist heat kills microbes
by denaturing protein and nucleic acid structures and disrupting cell membranes, which
takes less time to kill cells than removing water by dry heat and killing cells through
oxidation reactions.
Which of the following statements about pasteurization is not true?
A. Pasteurization reduces the microbial load in heat-sensitive liquids.
B. Pasteurization controls microbes that cause spoilage, such as E. coli and
Salmonella.
C. Pasteurization increases the shelf life of perishable liquids.
D. Pasteurization involves flash heating to 135°C for about a minute.
E. Pasteurization is a method of sterilization that kills microbes present in food. -
Answers - Pasteurization is a method sterilization that kill microbes present in food
(does not completely kill but reduces)
An autoclave is able to achieve temperatures higher than that of boiling water
____________
A. by decreasing the volume of liquid.
B. by increasing the temperature higher than boiling water.
C. by increasing the time of exposure to boiling water.
D. Actually, autoclaves cannot reach temperatures higher than boiling water.
E. by increasing the pressure. - Answers - e) increasing the pressure
Oxidizing agents such as chlorine or hydrogen peroxide are particularly effective against
_________ organisms.
A. microaerophilic
