MCB 100 EXAM 4 i-clickers Questions and Correct Answers
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Course
MCB 100
Institution
MCB 100
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 anti-parasitic agents.
-Bacteriostatic agents inhibit bacterial growth, but do not necessarily kill the organisms against wh...
MCB 100 EXAM 4 i-clickers Questions
and Correct Answers
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 anti-parasitic 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. ✅true- viruses
don't fall into this category, antimicrobial only refers to things that are growing
true- bacteriostatic means stay in place. They stop the growth of the bacteria until they
are removed. The advantage is you can prevent the lysis of a bacteria and an immune
cell can come along and clear it.
true- this is one of the best ways to make an antibacterial most effective. if you damage
the cell wall and the bacteria is still growing it makes it much more susceptible to the
bacteriostatic agent and it can actually end up being bactericidal by lysing the cells.
true
Moist heat kills microbes faster than dry heat because________ ✅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.
-dry heat takes longer and moist heat can penetrate a lot better and faster.
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 involves flash heating to 135 C for about a minute
d. Pasteurization is a method of sterilization that kills microbes present in food.
e. Pasteurization increases the shelf life of perishable liquids ✅d. Pasteurization is a
method of sterilization that kills microbes present in food.
, False because pasteurization does not kill all of the microbes present. It reduces the
microbial load, particularly in heat sensitive liquid.
When microbial control methods are used, microbes are destroyed at a constant rate;
there is no instantaneous death of all the microbes present. That microbial death rate is
influenced by all of the following factors EXCEPT __________.
a. the microbial physiological characteristics
b. the length of time of exposure to the treatment
c. the toxins and metabolites produced by the bacteria
d. the stability of the proteins in the bacteria
e. the number of microbes that are present ✅c. the toxins and metabolites produced
by the bacteria
**toxins and their metabolites don't have any influence on the rate at which a bacteria is
going to die
An autoclave is able to achieve temperatures higher than that of boiling
water_________ ✅by increasing the pressure
Oxidizing agents such as chlorine or hydrogen peroxide are particularly effective
against_______organisms. ✅anaerobic
oxidizing agents are going to be most effective against something that doesn't like
oxidized conditions.
Seventy percent alcohol and quaternary ammonium compounds are effective against
✅enveloped viruses
alcohol is a denaturant and a membrane perturber. Enveloped viruses are membrane
surrounded.
Contaminated hospital equipment represents a difficult environment to control harmful
microbial growth. Regarding influences that affect disinfection of hospital equipment,
which of the following is an accurate statement? ✅The cell walls of many Gram -
negative bacteria are especially resistant to many chemicals that are used to destroy
microbes
Which of the following is used to sterilize items that should not, or cannot, be exposed
to heat or water? ✅ethylene oxide
Which of the following antimicrobial agents is the most toxic to humans?
70% alcohol
quaternary ammonium compounds
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