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BIOL 203 MICROBIOLOGY LCC FINAL LATEST 2026-2027 ACTUAL
EXAM WITH COMPLETE QUESTIONS AND CORRECT DETAILED
ANSWERS (100% VERIFIED ANSWERS) |ALREADY GRADED A+|
||PROFESSOR VERIFIED|| ||BRANDNEW!!!||
While there are drugs available to treat viral infections, again, it is
a very small number compared to the number available to treat
bacterial infections. Explain why it is easier to develop a drug to
treat bacterial infections compared to developing a drug to treat
viral infections. Consider the life cycle of a virus in your answer. -
ANSWER-If they use the host cell to replicate, what can we target
to slow/stop replication without harming the host in the process?
Viruses have very few targets of their own to target (they are
genetic information and a protein coat.) To prevent them
from replicating you would need to target the host cell that
they have hijacked. This would also not be very selectively
toxic because it would cause damage to the host.
In 2015, the WHO surveyed 10,000 people on the subject of drug
resistance. Seventy-five percent of them said that antibiotic
resistance is due to the human body becoming resistant to the
drug. Explain how you would correct this misconception? -
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ANSWER-I would correct this micsconception by stating that the
body does not become resistant to the drug, instead, the antibiotic
is only killing some of the bacteria in the envirnment. This is due
to the selection pressure. There are small mutations in some of
the bacteria and some of those bacteria are highly susceptible to
that environment, while others are highly resistant and will not die.
There will now be open space/nutrients in the environment and
the bacteria, that are resistant to the drug, reproduce. This causes
more bacteria that are resistant to be in the environment and
hence why the drug is not "working" for that person.
Name and briefly describe the modes of action of the five major
antimicrobial drug groups. - ANSWER-1. Cell wall inhibitors- does
not allow the correct formation of the cell wall, leads to osmotic
shock and death.
2. Disruption of cell membrane- molecules that put themselves in
the cell membrane and disrupt the gate keepers abilites, leads to
leaky membranes and death.
3. Disruption of nucleic acid synthesis- prevents correct formation
and making of DNA for replication and RNA for protein syntheis.
,3|Page
4. Disruption of protein synthesis- prevents correct function of
ribosomes, leads to not being able to make proteins.
5. Disruption of metabolic pathways- acts as a mimic causing
cells to use the wrong starting substrate to inhibit the metabolic
pathway from making a cellular product.
Imagine that you have set up a Kirby Bauer experiment on
Mueller Hinton agar (non-selective agar) in order to test if
Escherichia coli is susceptible or resistant to Drug X. After 24
hours, you notice a zone of inhibition (clear zone) around your
antibiotic disc and determine that E. coli is susceptible to Drug X.
You then take a cotton swab and subculture a sample from this
zone of inhibition (where no growth was apparent) onto a new
agar plate without antibiotics and after 24 hours you see growth of
E.coli. What can you conclude about Drug X? Explain your
answer for full credit. - ANSWER-If resistant mutants were
present in the initial population, you would see them grow on the
first plate as well. The drug would have created space and freed
up nutrients for them. Do all antibiotic have to kill the bacteria to
be effective?
, 4|Page
Drug X is bacteriostatic - it slowed or stalled the growth of
Escherichia coli. We can determine this because once the
bacteria was removed from the presence of the antibiotic, it
grew again.
If Drug X had been bacteriocidal, then we would not have noticed
growth when the bacteria was removed from the presence of the
antibiotic because it would be dead.
Many visits to your physician do not result in a culture or a drug-
test of the causative infectious agent, yet you still leave with a
prescription for antibiotics. Name one instance where it would be
best to be prescribed a narrow spectrum antibiotic. Name a
second instance where it would be best to be prescribed a broad
spectrum antibiotic. Justify your answers for full credit. -
ANSWER-It wouls be best to prescribe a narrow spectrum
antibiotic when the infection is not life threatening or when the
doctor knows what bacteria is causing the infection. A narrow
spectrum antibiotic is used to be most effective on a small range
BIOL 203 MICROBIOLOGY LCC FINAL LATEST 2026-2027 ACTUAL
EXAM WITH COMPLETE QUESTIONS AND CORRECT DETAILED
ANSWERS (100% VERIFIED ANSWERS) |ALREADY GRADED A+|
||PROFESSOR VERIFIED|| ||BRANDNEW!!!||
While there are drugs available to treat viral infections, again, it is
a very small number compared to the number available to treat
bacterial infections. Explain why it is easier to develop a drug to
treat bacterial infections compared to developing a drug to treat
viral infections. Consider the life cycle of a virus in your answer. -
ANSWER-If they use the host cell to replicate, what can we target
to slow/stop replication without harming the host in the process?
Viruses have very few targets of their own to target (they are
genetic information and a protein coat.) To prevent them
from replicating you would need to target the host cell that
they have hijacked. This would also not be very selectively
toxic because it would cause damage to the host.
In 2015, the WHO surveyed 10,000 people on the subject of drug
resistance. Seventy-five percent of them said that antibiotic
resistance is due to the human body becoming resistant to the
drug. Explain how you would correct this misconception? -
,2|Page
ANSWER-I would correct this micsconception by stating that the
body does not become resistant to the drug, instead, the antibiotic
is only killing some of the bacteria in the envirnment. This is due
to the selection pressure. There are small mutations in some of
the bacteria and some of those bacteria are highly susceptible to
that environment, while others are highly resistant and will not die.
There will now be open space/nutrients in the environment and
the bacteria, that are resistant to the drug, reproduce. This causes
more bacteria that are resistant to be in the environment and
hence why the drug is not "working" for that person.
Name and briefly describe the modes of action of the five major
antimicrobial drug groups. - ANSWER-1. Cell wall inhibitors- does
not allow the correct formation of the cell wall, leads to osmotic
shock and death.
2. Disruption of cell membrane- molecules that put themselves in
the cell membrane and disrupt the gate keepers abilites, leads to
leaky membranes and death.
3. Disruption of nucleic acid synthesis- prevents correct formation
and making of DNA for replication and RNA for protein syntheis.
,3|Page
4. Disruption of protein synthesis- prevents correct function of
ribosomes, leads to not being able to make proteins.
5. Disruption of metabolic pathways- acts as a mimic causing
cells to use the wrong starting substrate to inhibit the metabolic
pathway from making a cellular product.
Imagine that you have set up a Kirby Bauer experiment on
Mueller Hinton agar (non-selective agar) in order to test if
Escherichia coli is susceptible or resistant to Drug X. After 24
hours, you notice a zone of inhibition (clear zone) around your
antibiotic disc and determine that E. coli is susceptible to Drug X.
You then take a cotton swab and subculture a sample from this
zone of inhibition (where no growth was apparent) onto a new
agar plate without antibiotics and after 24 hours you see growth of
E.coli. What can you conclude about Drug X? Explain your
answer for full credit. - ANSWER-If resistant mutants were
present in the initial population, you would see them grow on the
first plate as well. The drug would have created space and freed
up nutrients for them. Do all antibiotic have to kill the bacteria to
be effective?
, 4|Page
Drug X is bacteriostatic - it slowed or stalled the growth of
Escherichia coli. We can determine this because once the
bacteria was removed from the presence of the antibiotic, it
grew again.
If Drug X had been bacteriocidal, then we would not have noticed
growth when the bacteria was removed from the presence of the
antibiotic because it would be dead.
Many visits to your physician do not result in a culture or a drug-
test of the causative infectious agent, yet you still leave with a
prescription for antibiotics. Name one instance where it would be
best to be prescribed a narrow spectrum antibiotic. Name a
second instance where it would be best to be prescribed a broad
spectrum antibiotic. Justify your answers for full credit. -
ANSWER-It wouls be best to prescribe a narrow spectrum
antibiotic when the infection is not life threatening or when the
doctor knows what bacteria is causing the infection. A narrow
spectrum antibiotic is used to be most effective on a small range
