Question 1

PABA serves as the competitive inhibitor in the action of sulfanilamides.

Accepted Answer

A) True 
 B)False  False

Question 2

Which of the following drugs does NOT act by competitive inhibition?

Accepted Answer

A)  isoniazid 
B)  streptomycin 
C)  trimethoprim 
D)  ethambutol 
E)  sulfonamide 
A)  isoniazid 
B)  streptomycin 
C)  trimethoprim 
D)  ethambutol 
E)  sulfonamide B

Question 3

Which of the following antibiotics does NOT interfere with cell wall synthesis?

Accepted Answer

A)  cephalosporins 
B)  vancomycin 
C)  macrolides 
D)  natural penicillins 
E)  semisynthetic penicillins 
A)  cephalosporins 
B)  vancomycin 
C)  macrolides 
D)  natural penicillins 
E)  semisynthetic penicillins C

Question 4

Penicillin and streptomycin are commonly used in syngerism because they display the same mode of action.

Accepted Answer

A) True 
 B)False

Question 5

Figure 20.1
  
-The antibiotic tetracycline binds to the 30S subunit of the ribosome, as shown in Figure 20.1. The effect is to

Accepted Answer

A)  prevent attachment of DNA. 
B)  prevent transcription. 
C)  stop the ribosome from moving along the mRNA. 
D)  prevent peptide bond formation. 
E)  interfere with the attachment of the tRNA to mRNA- ribosome complex. 
A)  prevent attachment of DNA. 
B)  prevent transcription. 
C)  stop the ribosome from moving along the mRNA. 
D)  prevent peptide bond formation. 
E)  interfere with the attachment of the tRNA to mRNA- ribosome complex.

Question 6

Protozoan and helminthic diseases are difficult to treat because

Accepted Answer

A)  their cells are structurally and functionally similar to human cells. 
B)  they replicate inside human cells. 
C)  they have more genes than bacteria. 
D)  they do not reproduce. 
E)  they do not have ribosomes. 
A)  their cells are structurally and functionally similar to human cells. 
B)  they replicate inside human cells. 
C)  they have more genes than bacteria. 
D)  they do not reproduce. 
E)  they do not have ribosomes.

Question 7

Figure 20.3
  
-The substrate for transpeptidase used to synthesize peptidoglycan is shown in Figure 20.3. Which of the drugs shown would inhibit peptidoglycan synthesis?

Accepted Answer

A)  a 
B)  b 
C)  c 
D)  d 
E)  e 
A)  a 
B)  b 
C)  c 
D)  d 
E)  e

Question 8

Which of the following statements is FALSE?

Accepted Answer

A)  Acyclovir inhibits DNA synthesis. 
B)  Interferon inhibits glycolysis. 
C)  Amantadine inhibits the release of viral nucleic acid. 
D)  Azoles inhibit plasma membrane synthesis. 
E)  Fluoroquinolone inhibits DNA synthesis. 
A)  Acyclovir inhibits DNA synthesis. 
B)  Interferon inhibits glycolysis. 
C)  Amantadine inhibits the release of viral nucleic acid. 
D)  Azoles inhibit plasma membrane synthesis. 
E)  Fluoroquinolone inhibits DNA synthesis.

Question 9

Most of the available antimicrobial agents are effective against

Accepted Answer

A)  fungi. 
B)  viruses. 
C)  bacteria. 
D)  protozoa. 
E)  All of the answers are correct. 
A)  fungi. 
B)  viruses. 
C)  bacteria. 
D)  protozoa. 
E)  All of the answers are correct.

Question 10

Which compound would be the most useful to treat candidiasis?

Accepted Answer

A)  penicillin 
B)  guanine 
C)  uracil 
D)  thymine 
E)  flucytosine 
A)  penicillin 
B)  guanine 
C)  uracil 
D)  thymine 
E)  flucytosine

Question 11

More than half of our antibiotics are

Accepted Answer

A)  produced by Fleming. 
B)  produced by fungi. 
C)  produced by eukaryotic organisms. 
D)  produced by bacteria. 
E)  synthesized in laboratories. 
A)  produced by Fleming. 
B)  produced by fungi. 
C)  produced by eukaryotic organisms. 
D)  produced by bacteria. 
E)  synthesized in laboratories.

Question 12

Which of the following organisms would MOST likely be sensitive to natural penicillin?

Accepted Answer

A)  Penicillium 
B)  penicillinase- producing Neisseria gonorrhoeae 
C)  Streptococcus pyogenes 
D)  helminths 
E)  Mycoplasma 
A)  Penicillium 
B)  penicillinase- producing Neisseria gonorrhoeae 
C)  Streptococcus pyogenes 
D)  helminths 
E)  Mycoplasma

Question 13

Table 20.3
The following data were obtained from a broth dilution test: $\begin{array} { | c | c | } 
\hline \text { Concentration of Antibiotic } \mathrm { X } & \text { Growth } \
\hline 2.0 \mu \mathrm { g } / \mathrm { ml } & \
\hline 1.0 \mu \mathrm { g } / \mathrm { ml } & \
\hline 0.5 \mu \mathrm { g } / \mathrm { ml } & \
\hline 0.25 \mu \mathrm { g } / \mathrm { ml } & + \
\hline 0.125 \mu \mathrm { g } / \mathrm { ml } & + \
\hline 0 & + \
\hline
\end{array}$ Bacteria from the 0.25 µg/ml tube were transferred to new growth media containing antibiotic X with the following results: $\begin{array} { | c | l | } 
\hline \text { Concentration of Antibiotic X } & \text { Growth } \
\hline 2.0 \mu \mathrm { g } / \mathrm { ml } & \
\hline 1.0 \mu \mathrm { g } / \mathrm { ml } & + \
\hline 0.5 \mu \mathrm { g } / \mathrm { ml } & + \
\hline 0.25 \mu \mathrm { g } / \mathrm { ml } & + \
\hline
\end{array}$
-The data in Table 20.3 show that these bacteria

Accepted Answer

A)  developed resistance to antibiotics. 
B)  are pathogenic. 
C)  were killed by 0.5 µg/ml of antibiotic X. 
D)  were killed by 0.125 µg/ml of antibiotic X. 
E)  were resistant to 1.0 µg/ml at the start of the experiment. 
A)  developed resistance to antibiotics. 
B)  are pathogenic. 
C)  were killed by 0.5 µg/ml of antibiotic X. 
D)  were killed by 0.125 µg/ml of antibiotic X. 
E)  were resistant to 1.0 µg/ml at the start of the experiment.

Question 14

Which of the following antibiotics is recommended for use against gram- negative bacteria?

Accepted Answer

A)  polymyxin 
B)  cephalosporin 
C)  bacitracin 
D)  polyenes 
E)  penicillin 
A)  polymyxin 
B)  cephalosporin 
C)  bacitracin 
D)  polyenes 
E)  penicillin

Question 15

Mebendazole is used to treat cestode infections. It interferes with microtubule formation; therefore, it would NOT affect

Accepted Answer

A)  human cells. 
B)  fungi. 
C)  protozoa. 
D)  helminths. 
E)  bacteria. 
A)  human cells. 
B)  fungi. 
C)  protozoa. 
D)  helminths. 
E)  bacteria.

Question 16

Which of the following antimicrobial agents is recommended for use against fungal infections?

Accepted Answer

A)  polymyxin 
B)  amphotericin B 
C)  cephalosporin 
D)  penicillin 
E)  bacitracin 
A)  polymyxin 
B)  amphotericin B 
C)  cephalosporin 
D)  penicillin 
E)  bacitracin

Question 17

Penicillin was considered a "miracle drug" for all of the following reasons EXCEPT

Accepted Answer

A)  it was the first antibiotic. 
B)  it inhibits gram- positive cell wall synthesis. 
C)  it does not affect eukaryotic cells. 
D)  it kills bacteria. 
E)  it has selective toxicity. 
A)  it was the first antibiotic. 
B)  it inhibits gram- positive cell wall synthesis. 
C)  it does not affect eukaryotic cells. 
D)  it kills bacteria. 
E)  it has selective toxicity.

Question 18

In Table 20.2, the antibiotic that exhibited bactericidal action was

Accepted Answer

A)  A. 
B)  B. 
C)  C. 
D)  D. 
E)  The answer cannot be determined based on the information provided. 
A)  A. 
B)  B. 
C)  C. 
D)  D. 
E)  The answer cannot be determined based on the information provided.

Question 19

In what way are semisynthetic penicillins and natural penicillins alike?

Accepted Answer

A)  Both are resistant to penicillinase. 
B)  Both are resistant to stomach acids. 
C)  Both are bactericidal. 
D)  Both are based on fi- lactam. 
E)  Both are broad spectrum. 
A)  Both are resistant to penicillinase. 
B)  Both are resistant to stomach acids. 
C)  Both are bactericidal. 
D)  Both are based on fi- lactam. 
E)  Both are broad spectrum.

Question 20

Drug resistance occurs

Accepted Answer

A)  when antibiotics are used indiscriminately. 
B)  against antibiotics and not against synthetic chemotherapeutic agents. 
C)  when antibiotics are taken after the symptoms disappear. 
D)  because bacteria are normal microbiota. 
E)  All of the answers are correct. 
A)  when antibiotics are used indiscriminately. 
B)  against antibiotics and not against synthetic chemotherapeutic agents. 
C)  when antibiotics are taken after the symptoms disappear. 
D)  because bacteria are normal microbiota. 
E)  All of the answers are correct.

Exam 20: Antimicrobial Drugs

PABA serves as the competitive inhibitor in the action of sulfanilamides.

Which of the following drugs does NOT act by competitive inhibition?

Which of the following antibiotics does NOT interfere with cell wall synthesis?

Penicillin and streptomycin are commonly used in syngerism because they display the same mode of action.

Figure 20.1 -The antibiotic tetracycline binds to the 30S subunit of the ribosome, as shown in Figure 20.1. The effect is to

Protozoan and helminthic diseases are difficult to treat because

Figure 20.3 -The substrate for transpeptidase used to synthesize peptidoglycan is shown in Figure 20.3. Which of the drugs shown would inhibit peptidoglycan synthesis?

Which of the following statements is FALSE?

Most of the available antimicrobial agents are effective against

Which compound would be the most useful to treat candidiasis?

More than half of our antibiotics are

Which of the following organisms would MOST likely be sensitive to natural penicillin?

Which of the following antibiotics is recommended for use against gram- negative bacteria?

Mebendazole is used to treat cestode infections. It interferes with microtubule formation; therefore, it would NOT affect

Which of the following antimicrobial agents is recommended for use against fungal infections?

Penicillin was considered a "miracle drug" for all of the following reasons EXCEPT

In Table 20.2, the antibiotic that exhibited bactericidal action was

In what way are semisynthetic penicillins and natural penicillins alike?

Drug resistance occurs

The Microbial World and You

Chemical Principles

Observing Microorganisms Through a Microscope

Functional Anatomy of Prokaryotic and Eukaryotic Cells

Microbial Metabolism

Microbial Growth

The Control of Microbial Growth

Microbial Genetics

Biotechnology and Recombinant Dna

Classification of Microorganisms

The Prokaryotes: Domains Bacteria and Archaea

The Eukaryotes: Fungi, Algae, Protozoa, and Helminths

Viruses, Viroids, and Prions

Principles of Disease and Epidemiology

Microbial Mechanisms of Pathogenicity

Innate Immunity: Nonspecific Defenses of the Host

Adaptive Immunity: Specific Defenses of the Host

Practical Applications of Immunology

Disorders Associated With the Immune System

Microbial Diseases of the Skin and Eyes

Microbial Diseases of the Nervous System

Microbial Diseases of the Cardiovascular and Lymphatic Systems

Microbial Diseases of the Respiratory System

Microbial Diseases of the Digestive System

Microbial Diseases of the Urinary and Reproductive Systems

Environmental Microbiology

Applied and Industrial Microbiology

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