Question 1

Several diseases caused by herpesviruses are treated with a medication called acyclovir. This medication is a nucleoside analog, meaning

Accepted Answer

A)   it contains a nucleotide analog and a phosphate.
B)   it contains a nucleotide analog, a phosphate, and a sugar.
C)   it contains a nucleotide analog and a sugar.
D)   it is composed of NAG, NAM, and tetrapeptides.
E)   it is composed of NAG, NAM, and a sugar.F) All of the above
G) A) and E)

Question 2

The situation in which the effect of two antimcrobials given together is more effective than the effect of either medication given individually is referred to as

Accepted Answer

A)   synergism.
B)   antagonism.
C)   nihilism.
D)   symbiosis.
E)   dysbiosis.F) A) and C)
G) A) and B)

Question 3

The target of most antifungal drugs is

Accepted Answer

A)   the ribosome AND the cytoplasmic membrane.
B)   the nucleus AND mitochondria.
C)   cholesterol.
D)   ergosterol.
E)   cholesterol AND ergosterol.F) A) and C)
G) B) and C)

Question 4

The lowest concentration of a drug that prevents growth of a microorganism is the

Accepted Answer

A)   infectious effective dose.
B)   minimum inhibitory concentration.
C)   lethal dose.
D)   most effective concentration.
E)   minimal death dose.F) A) and E)
G) None of the above

Question 5

The most effective form of penicillin is

Accepted Answer

A)   penicillin A.
B)   penicillin B.
C)   penicillin E.
D)   penicillin G.
E)   penicillium.F) A) and B)
G) C) and D)

Question 6

The arsenic compound that proved highly effective in treating syphilis was called

Accepted Answer

A)   penicillin.
B)   sulfa.
C)   erythromycin.
D)   Salvarsan.
E)   erlichsan.F) B) and C)
G) A) and E)

Question 7

The MBC may be determined by an extension of the MIC.

Accepted Answer

A) True 
 B)False

Question 8

Why would antimicrobials that have toxic side effects be used at all? (select the BEST reason)

Accepted Answer

A)   We want the largest possible number of choices of drugs in case a microbe shows resistance. With more possible weapons (even toxic ones) , we have greater ability to eliminate infections.
B)   Every person is different.  What is toxic to one person may not be toxic to another person. To eliminate a useful drug because it's toxic to 1% of people treated is a waste.
C)   Depending on the location of the infection, we may have no choice but to utilize a drug that has some toxic side effects to the patient.
D)   They shouldn't be used. We have enough of a selection of drugs that we can always select a drug with no toxicity. Drugs with toxicity are simply leftovers from a time when we didn't have as many drug options.
E)   These are all reasons to use antimicrobials that have a low therapeutic index.F) A) and E)
G) A) and D)

Question 9

Inhibitors of protein synthesis typically act on

Accepted Answer

A)   peptidoglycan precursors.
B)   penicillin-binding proteins.
C)   ribosomes.
D)   porin proteins.
E)   transfer RNA.F) A) and B)
G) A) and C)

Question 10

Acyclovir interferes with viral DNA replication. Other mechanisms of antiviral medications include all of the following EXCEPT

Accepted Answer

A)   preventing fusion and inhibiting viral entry into a host cell.
B)   interfering with viral uncoating and release of viral nucleic acid in a host cell.
C)   preventing the assembly viral proteins to form capsids.
D)   inhibition of viral particle release from host cells.
E)   destroying viral ribosomes and preventing protein synthesis.F) B) and E)
G) None of the above

Question 11

The minimum bactericidal concentration is the lowest concentration of a specific antimicrobial drug that kills ________ of a specific type of bacteria.

Accepted Answer

A)   10%
B)   50%
C)   99.9%
D)   100%
E)   25%F) A) and E)
G) A) and C)

Question 12

Please select the True statement regarding bacterial resistance to antimicrobials.

Accepted Answer

A)   Gram-positive bacteria are intrinsically resistant to certain medications because the lipid bilayer of their outer membrane prevents the molecules from entering.
B)   Intrinsic resistance  generally occurs through spontaneous mutation or horizontal gene transfer.
C)   The genes for antimicrobial resistance are often carried on fertility plasmids (F plasmids) .
D)   Mycoplasma species lack a cell wall, so they are resistant to penicillin that interferes with peptidoglycan synthesis. This is an example of intrinsic resistance.
E)   Acquired resistance is very limited because microorganisms cannot evolve, so are incapable of developing mechanisms to avoid the effects of medications. F) B) and E)
G) A) and D)

Question 13

Please select the False statement regarding antibiotic resistance.

Accepted Answer

A)   Modifications in the penicillin-binding proteins (PBPs)  prevent β-lactam antibiotics from binding to them.
B)   Some antibiotic-inactivating enzymes have an extended spectrum and confer resistance to a wide variety of antibiotics.
C)   Changes in the porin proteins can prevent certain antimicrobials from entering a cell's periplasm or cytoplasm.
D)   The bacterial enzyme chloramphenicol acetyltransferase confers resistance to the penicillins.
E)   Bacteria that produce efflux pumps sometimes become resistant to several different antimicrobials simultaneously.F) None of the above
G) A) and D)

Question 14

Compliance problems are leading to a large increase in antibiotic resistant strains of

Accepted Answer

A)   Mycobacterium.
B)   Streptococcus.
C)   Staphylococcus.
D)   Pseudomonas.
E)   Mycoplasma.F) B) and E)
G) None of the above

Question 15

Which of the following drugs does NOT target peptidoglycan?

Accepted Answer

A)   Penicillin
B)   Cephalosporin
C)   Vancomycin
D)   Bacitracin
E)   DoxycyclineF) D) and E)
G) A) and E)

Question 16

The major class(es)  of antibiotics that inhibit protein synthesis include all of the following EXCEPT

Accepted Answer

A)   bacitracins.
B)   aminoglycosides.
C)   tetracyclines.
D)   macrolides.
E)   streptogramins.F) A) and B)
G) A) and C)

Question 17

Explain how using a combination of two antimicrobial drugs helps prevent the development of spontaneously resistant mutants.

Accepted Answer

A)   All drugs work synergistically with each other. Their combined effects are far greater than either could achieve individually. Two drugs together helps to eliminate microbes, even if they have developed spontaneous mutations that would make them resistant to the drugs.
B)   It is highly unlikely that the microbe might spontaneously develop two specific mutations to resist the effects of a pair of drugs. As such, even if one drug is resisted by the microbe, the second drug will eliminate the mutated microbe, thus preventing the development of spontaneously resistant mutants overall.
C)   All drugs work antagonistically with each other. Their combined effects are far greater than either could achieve individually. Two drugs together helps to eliminate microbes, even if they have developed spontaneous mutations that would make them resistant to the drugs.
D)   Drugs can also select for mutations that will enhance the activity of another drug. Therefore, each of the paired drugs will help to select for spontaneous mutations that enhance the activity of the other drug in the pair.
E)   Bacteria can only ever develop resistance to a single antibiotic. If more than one drug is used, the organisms will definitely become resistant to one of them but it will not become resistant to both of them. The second antibiotic will kill the organism.F) A) and E)
G) C) and E)

Question 18

What is the minimum inhibitory concentration (MIC) ?

Accepted Answer

A)   It is the lowest concentration of a specific antimicrobial medication needed to prevent the visible growth of a given bacterial strain in vitro.
B)   It is the highest concentration of a specific antimicrobial medication needed to prevent the visible growth of a given bacterial strain in vitro.
C)   It is the lowest concentration of a specific antimicrobial medication needed to prevent the visible growth of a given bacterial strain in vivo.
D)   It is the highest concentration of a specific antimicrobial medication needed to prevent the visible growth of a given bacterial strain in vivo.
E)   It is the lowest concentration of a specific antimicrobial medication that kills 99.9% of cells of a given bacterial strain in vitro.F) All of the above
G) None of the above

Question 19

Spontaneous development of resistance to a particular antimicrobial is difficult if the drug

Accepted Answer

A)   targets a single type of molecule AND binds to a single site on that target molecule.
B)   targets several different molecules AND affects the cytoplasmic membrane.
C)   affects only one molecule.
D)   affects the cytoplasmic membrane.
E)   binds to several sites on the target molecule AND targets several different molecules.F) C) and D)
G) B) and D)

Question 20

Why would co-administration of a bacteriostatic drug interfere with the effects of penicillin?

Accepted Answer

A)   Since most bacteriostatic drugs are produced from bacteria but penicillin is produced from mold, the two drugs are incompatible with each other.
B)   A bacteriostatic drug interferes with the ability of a bacterial cell to take in compounds from the outside environment. Penicillin must be taken in by the cell in order to have its effect, so this would directly inhibit it.
C)   The bacteriostatic drugs would bind directly to the penicillin, preventing both its uptake by the cell and its ability to perform its duty within the bacterial cell.
D)   Penicillin interferes with cell wall production so it only works when the cells are actively replicating and MAKING new peptidoglycan. A bacteriostatic drug works by shutting down replication, holding the cells "static." This would interfere with the mode of action required by the penicillin.
E)   Nothing interferes with the effects of penicillin. It is the most effective medication that we have, so is never used with the addition of a second drug when treating a person.F) A) and D)
G) A) and E)

Exam 20: Antimicrobial Medications

Please select the False statement regarding antibiotic resistance.

Correct AnswerverifiedShow Answer

Which of the following drugs does NOT target peptidoglycan?

Correct AnswerverifiedShow Answer

Acyclovir interferes with viral DNA replication. Other mechanisms of antiviral medications include all of the following EXCEPT

Correct AnswerverifiedShow Answer

Inhibitors of protein synthesis typically act on

Correct AnswerverifiedShow Answer

What is the minimum inhibitory concentration (MIC) ?

Correct AnswerverifiedShow Answer

The MBC may be determined by an extension of the MIC.

Correct AnswerverifiedShow Answer

Why would antimicrobials that have toxic side effects be used at all? (select the BEST reason)

Correct AnswerverifiedShow Answer

The lowest concentration of a drug that prevents growth of a microorganism is the

Correct AnswerverifiedShow Answer

The situation in which the effect of two antimcrobials given together is more effective than the effect of either medication given individually is referred to as

Correct AnswerverifiedShow Answer

The target of most antifungal drugs is

Correct AnswerverifiedShow Answer

Several diseases caused by herpesviruses are treated with a medication called acyclovir. This medication is a nucleoside analog, meaning

Correct AnswerverifiedShow Answer

Explain how using a combination of two antimicrobial drugs helps prevent the development of spontaneously resistant mutants.

Correct AnswerverifiedShow Answer

Please select the True statement regarding bacterial resistance to antimicrobials.

Correct AnswerverifiedShow Answer

The arsenic compound that proved highly effective in treating syphilis was called

Correct AnswerverifiedShow Answer

The minimum bactericidal concentration is the lowest concentration of a specific antimicrobial drug that kills ________ of a specific type of bacteria.

Correct AnswerverifiedShow Answer

Spontaneous development of resistance to a particular antimicrobial is difficult if the drug

Correct AnswerverifiedShow Answer

The major class(es) of antibiotics that inhibit protein synthesis include all of the following EXCEPT

Correct AnswerverifiedShow Answer

Compliance problems are leading to a large increase in antibiotic resistant strains of

Correct AnswerverifiedShow Answer

Why would co-administration of a bacteriostatic drug interfere with the effects of penicillin?

Correct AnswerverifiedShow Answer

The most effective form of penicillin is

Correct AnswerverifiedShow Answer

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