This document is a study guide containing questions and answers about antibiotic resistance in bacteria. It discusses various mechanisms of resistance such as efflux pumps, altered targets, and enzymatic inactivation. Mutations and horizontal gene transfer allow bacteria to become resistant to antibiotics. The key is that resistance arises when bacteria are no longer killed or inhibited by a drug they were previously sensitive to.

1. Upgrade
Profi
mastering micro Chapter 20
Science Biology Microbiology
Terms in this set (21)
What is meant by selective
toxicity?
A) Chemotherapeutic agents
should have only one mode of
action.
B) Chemotherapeutic agents
should work on many different
targets on a pathogen.
C) Chemotherapeutic agents
should act against the
pathogen and not the host.
D) Chemotherapeutic agents
should work on certain types
of pathogens.
C) Chemotherapeutic agents should act against the
pathogen and not the host.
mastering micro Chapter 20 Study

2. Why are chemotherapeutic
agents that work on the
peptidoglycan cell wall of
bacteria a good choice of
drug?
A) They are less expensive that
other chemotherapeutic
agents.
B) Humans and other animal
hosts lack peptidoglycan cell
walls.
C) The drugs also work against
DNA gyrase.
D) Bacteria are especially
sensitive to these compounds.
B) Humans and other animal hosts lack
peptidoglycan cell walls.
Why is polymyxin only used on
the skin?
A) It can also damage living
human cell membranes, but the
drug is safely used on the skin,
where the outer layers of cells
are dead.
B) It can disrupt the metabolic
pathways found in humans.
C) It is sensitive to degradation
by acid, making oral delivery
unsuitable.
D) It has no effect on bacteria
that live in the GI tract.
A) It can also damage living human cell membranes,
but the drug is safely used on the skin, where the
outer layers of cells are dead.
mastering micro Chapter 20 Study

3. Quinolones and
fluoroquinolones act against
what bacterial target?
Metabolic pathways unique to
bacteria
Cell walls
Cell membranes
DNA gyrase
Bacterial ribosomes
DNA gyrase
Why is it difficult to find good
chemotherapeutic agents
against viruses?
A) Viruses depend on the host
cell's machinery, so it is hard to
find a viral target that would
leave the host cell unaffected.
B) Viruses infect both bacteria
and human cells.
C) Viruses are not cells, and
therefore not sensitive to such
compounds.
D) There is no effective way to
deliver the drug to the virus.
A) Viruses depend on the host cell's machinery, so it
is hard to find a viral target that would leave the
host cell unaffected.
If penicillin G is chosen as the
best treatment for a given
infection, what microorganisms
are most likely the cause?
viruses
gram-positive bacteria
fungi
gram-negative bacteria
gram-positive bacteria
mastering micro Chapter 20 Study

4. Why is it more difficult to treat
viral infections than it is to treat
bacterial infections?
A) Viruses have cell walls.
B) Viruses are smaller than
human cells.
C) Viruses use the host cell's
processes to carry out their
own reproduction.
D) Viruses are very similar to
human cells.
C) Viruses use the host cell's processes to carry out
their own reproduction.
Sulfanilamides interfere with
__________.
protein synthesis in helminths
anaerobic metabolism in
protozoa
folic acid synthesis in bacteria
protein synthesis in fungi
folic acid synthesis in bacteria
mastering micro Chapter 20 Study

5. Certain cancer cells have ABC
transport molecules at the cell
surface. These transporters use
energy from ATP to move
chemotherapeutic agents out
of the cell. Which of the
following do you think these
transporters are most closely
related to?
altered porins
membrane pumps
conjugation pilus
beta-lactamase
membrane pumps
mastering micro Chapter 20 Study

6. A researcher creates an
antibiotic that binds to a
protein present only on B.
anthracis (the causative agent
of anthrax), lysing the cell from
the outside. After a couple of
years using this antibiotic, some
resistant organisms are found.
Which of the following best
outlines the mechanism for
development of this
resistance?
A) cell division of B. anthracis
→ altered target → resistant
bacterium
B) mutation in B. anthracis →
altered target → resistant
bacterium
C) mutation in B. anthracis →
altered porins → resistant
bacterium
D) cell division of B. anthracis
→ altered porins → resistant
bacterium
B) mutation in B. anthracis → altered target →
resistant bacterium
mastering micro Chapter 20 Study

7. A new bacterial molecule is
discovered. This molecule
binds to an antibiotic and
facilitates the binding of a
phosphate group, thus
inactivating the antibiotic.
Which category best describes
the mechanism of antibiotic
resistance conferred by this
molecule?
rapid efflux of the antibiotic
conjugation
altered porins
bacterial enzymes
bacterial enzymes
Which antibiotic is overcome
by beta-lactamases?
Tetracycline
Sulfonamide
Penicillin
Tetracycline, Penicillin, and
Sulfonamide are all affected by
beta-lactamase.
Tetracycline, Penicillin, and Sulfonamide are all
affected by beta-lactamase.
mastering micro Chapter 20 Study

8. How might efflux pumps
increase antibiotic resistance in
bacteria?
A) Resistant bacteria may have
a greater number of efflux
pumps on their cell surfaces.
B) Some bacteria can decrease
the specificity of their efflux
pumps, increasing the number
of different antibiotics the
pumps can eliminate.
C) Some bacteria can change
the chemical structure of the
antibiotic.
D) Efflux pumps can never be
modified to increase antibiotic
resistance.
E) Resistant bacteria can have
more efflux pumps, and can
have less specific efflux pumps.
E) Resistant bacteria can have more efflux pumps,
and can have less specific efflux pumps.
Bacteria that are resistant to
sulfonamide have enzymes that
have a greater affinity for what?
PABA
Sulfonamide
Tetrahyrdrofolic acid
Tetracycline
PABA
mastering micro Chapter 20 Study

9. Why would an efflux pump for
penicillin located on a bacterial
cell membrane not be effective
at providing resistance to the
drug?
A) The efflux pumps would not
stop penicillin from blocking
metabolic pathways.
B) There are fewer efflux
pumps on the cell membrane.
C) The cell membrane is the
target of penicillin.
D) Penicillin disrupts the cell
wall, which is located outside
of the cell membrane.
D) Penicillin disrupts the cell wall, which is located
outside of the cell membrane.
Membrane transport proteins
are required for which mode(s)
of antibiotic resistance?
A) Efflux pumps, beta-
lactamases, and modification
of porins all utilize membrane
transport proteins.
B) Efflux pumps
C) Modification of a metabolic
enzyme
D) Modification of a porins
E) Beta-lactamases
A) Efflux pumps, beta-lactamases, and modification
of porins all utilize membrane transport proteins.
mastering micro Chapter 20 Study

10. What is meant when a
bacterium is said to become
"resistant" to an antibiotic?
A) The antibiotic kills or inhibits
the bacterium.
B) The antibiotic is metabolized
by the bacterium, providing
more energy for growth of the
cell.
C) The bacterium is neither
killed nor inhibited by the
antibiotic.
D) The antibiotic mutates in a
way that benefits the
bacterium.
C) The bacterium is neither killed nor inhibited by
the antibiotic.
When a patient is treated with
antibiotics, __________.
A) mutations occur in all of the
bacterial cells
B) sensitive bacterial cells
multiply uncontrollably
C) the drug will kill or inhibit
the growth of all of the
sensitive bacterial cells
D) the drug will kill or inhibit
the growth of all of the
resistant bacterial cells
E) mutations will occur in the
sensitive bacterial cells, but not
in the resistant bacterial cells
C) the drug will kill or inhibit the growth of all of the
sensitive bacterial cells
mastering micro Chapter 20 Study

11. The process of acquiring
antibiotic resistance by means
of bacteriophage activity is
called
transduction.
R-plasmid acquisition.
point mutation.
transformation.
R-plasmid acquisition.
Which of the following
mutations would not result in
antibiotic resistance?
Missense mutation
Nonsense mutation
Silent mutation
Frameshift insertion
Frameshift deletion
Silent mutation
R-plasmids are most likely
acquired via
Check all that apply.
transduction.
transformation.
bacterial conjugation.
translation.
bacterial conjugation.
mastering micro Chapter 20 Study