Question 1

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

Accepted Answer

A) True 
 B)False

Question 2

Both trimethoprim and sulfamethoxazole inhibit reactions along the same metabolic pathway.

Accepted Answer

A) True 
 B)False

Question 3

Which of the following statements about drugs that competitively inhibit DNA polymerase or RNA polymerase is FALSE?

Accepted Answer

A)  They are used against viral infections. 
B)  They cause cellular plasmolysis. 
C)  They can affect host cell DNA synthesis. 
D)  They interfere with protein synthesis. 
E)  They can potentially cause mutations. 
A)  They are used against viral infections. 
B)  They cause cellular plasmolysis. 
C)  They can affect host cell DNA synthesis. 
D)  They interfere with protein synthesis. 
E)  They can potentially cause mutations.

Question 4

Which of the following antimicrobial agents has the fewest side effects?

Accepted Answer

A)  streptomycin 
B)  chloramphenicol 
C)  erythromycin 
D)  penicillin 
E)  tetracycline 
A)  streptomycin 
B)  chloramphenicol 
C)  erythromycin 
D)  penicillin 
E)  tetracycline

Question 5

Drug resistance occurs

Accepted Answer

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

Question 6

In the presence of penicillin, a cell dies because

Accepted Answer

A)  it lacks a cell membrane. 
B)  it undergoes lysis. 
C)  its contents leak out. 
D)  it lacks a cell wall. 
E)  it plasmolyzes. 
A)  it lacks a cell membrane. 
B)  it undergoes lysis. 
C)  its contents leak out. 
D)  it lacks a cell wall. 
E)  it plasmolyzes.

Question 7

Figure 20.2   The antibiotic chloramphenicol binds to the 50S subunit of the ribosome, as shown in Figure 20.2. The effect is to

Accepted Answer

A)  prevent peptide bond formation in prokaryotes. 
B)  prevent transcription in prokaryotes. 
C)  prevent polypeptide elongation in eukaryotes. 
D)  prevent ribosome formation in bacteria. 
E)  prevent mRNA-ribosome binding in eukaryotes. 
A)  prevent peptide bond formation in prokaryotes. 
B)  prevent transcription in prokaryotes. 
C)  prevent polypeptide elongation in eukaryotes. 
D)  prevent ribosome formation in bacteria. 
E)  prevent mRNA-ribosome binding in eukaryotes.

Question 8

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

Accepted Answer

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

Question 9

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

Accepted Answer

A) True 
 B)False

Question 10

Table 20.1
The following data were obtained from a broth dilution test. $\begin{array}{|l|l|l|}
\hline\text { Concentration of AntibioticX } & \text { Growth } & \frac{\text { Growth in }}{\text { Subculture }} \\hline 2 \mu \mathrm{g} / \mathrm{ml} & + & + \
\hline 10 \mu \mathrm{g} / \mathrm{ml} & - & + \
\hline 15 \mu \mathrm{g} / \mathrm{ml} & - & - \
\hline 25 \mu \mathrm{g} / \mathrm{ml} & - & - \
 \hline
\end{array}$
-5) In Table 20.1, as illustrated by the data shown, the minimal bactericidal concentration of antibiotic X is

Accepted Answer

A)  10 ?g/ml. 
B)  2 ?g/ml. 
C)  25 ?g/ml. 
D)  15 ?g/ml. 
E)  The answer cannot be determined based on the information provided. 
A)  10 ?g/ml. 
B)  2 ?g/ml. 
C)  25 ?g/ml. 
D)  15 ?g/ml. 
E)  The answer cannot be determined based on the information provided.

Question 11

Niclosamide prevents ATP generation in mitochondria. You would expect this drug to be effective against

Accepted Answer

A)  helminths. 
B)  gram-positive bacteria. 
C)  Mycobacterium tuberculosis. 
D)  viruses. 
E)  gram-negative bacteria. 
A)  helminths. 
B)  gram-positive bacteria. 
C)  Mycobacterium tuberculosis. 
D)  viruses. 
E)  gram-negative bacteria.

Question 12

A drug that inhibits mitosis, such as griseofulvin, would be more effective against

Accepted Answer

A)  fungi. 
B)  gram-positive bacteria. 
C)  mycobacteria. 
D)  wall-less bacteria. 
E)  gram-negative bacteria. 
A)  fungi. 
B)  gram-positive bacteria. 
C)  mycobacteria. 
D)  wall-less bacteria. 
E)  gram-negative bacteria.

Question 13

Due to its target, rifamycins can be effective over a broad spectrum.

Accepted Answer

A) True 
 B)False

Question 14

Explain why penicillin was called the ʺmiracle drugʺ when it was first used in the 1940s.

Accepted Answer

The answer of Explain why penicillin was called the ʺmiracle...

Question 15

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

Accepted Answer

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

Question 16

In what way are semisynthetic penicillins and natural penicillins alike?

Accepted Answer

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

Question 17

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

Accepted Answer

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

Question 18

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 19

Undergrowth of fungi after antibiotic use is commonly referred to as a superinfection.

Accepted Answer

A) True 
 B)False

Question 20

To date, most of our natural antibiotics have been found to be produced by members of what genus?

Accepted Answer

A)  Bacillus 
B)  Paenibacillus 
C)  Streptomyces 
D)  Penicillium 
E)  Cephalosporium 
A)  Bacillus 
B)  Paenibacillus 
C)  Streptomyces 
D)  Penicillium 
E)  Cephalosporium

Exam 20: Antimicrobial Drugs

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

Both trimethoprim and sulfamethoxazole inhibit reactions along the same metabolic pathway.

Which of the following statements about drugs that competitively inhibit DNA polymerase or RNA polymerase is FALSE?

Which of the following antimicrobial agents has the fewest side effects?

Drug resistance occurs

In the presence of penicillin, a cell dies because

Figure 20.2 The antibiotic chloramphenicol binds to the 50S subunit of the ribosome, as shown in Figure 20.2. The effect is to

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

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

Table 20.1 The following data were obtained from a broth dilution test. Concentration of AntibioticX Growth 2\mu/ + + 10\mu/ - + 15\mu/ - - 25\mu/ - - -5) In Table 20.1, as illustrated by the data shown, the minimal bactericidal concentration of antibiotic X is

Niclosamide prevents ATP generation in mitochondria. You would expect this drug to be effective against

A drug that inhibits mitosis, such as griseofulvin, would be more effective against

Due to its target, rifamycins can be effective over a broad spectrum.

Explain why penicillin was called the ʺmiracle drugʺ when it was first used in the 1940s.

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

In what way are semisynthetic penicillins and natural penicillins alike?

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?

Undergrowth of fungi after antibiotic use is commonly referred to as a superinfection.

To date, most of our natural antibiotics have been found to be produced by members of what genus?

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 Dna Technology

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 Disease of the Urinary and Reproductive Systems

Environmental Microbiology

Applied and Industrial Microbiology

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