MMBIO 221 TEST QUESTIONS AND ANSWERS A+
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Isoniazid: synthetic or antibiotic; method of action; principle use
synthetic, vitamin B6 analog, tuberculosis
Sulfonamides: synthetic or antibiotic; method of action; principle use
synthetic, inhibit folic acid synthesis, gram-negative bacteria
Ethambutol: synthetic or antibiotic; method of action; principle use
synthetic, competitive inhibitor, tuberculosis
Trimethoprim: synthetic or antibiotic; method of action; principle use
synthetic, inhibit folic acid synthesis, Pnumocystis and UTIs
Fluoroquinolones: synthetic or antibiotic; method of action; principle use
synthetic, inhibit DNA synthesis, UTIs
Penicillin, natural: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit cell wall synthesis, gram-positive bacteria
Penicillin, synthetic: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit cell wall synthesis, broad spectrum
Cephalosporins: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit cell wall synthesis, broad spectrum
Carbapenems: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit cell wall synthesis, broad spectrum
Aminoglycosides: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit protein synthesis, gram-negative bacteria
Tetracyclines: synthetic or antibiotic; method of action; principle use
inhibit protein synthesis, broad spectrum
Chloramphenicol: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit protein synthesis, life-threatening infection
Macrolides: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit protein synthesis, gram-negative bacteria
Polypeptides: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit cell wall synthesis, injure plasma membrane, gram-positive and
negative bactiera
Vancomycin: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit cell wall synthesis, penicillin-resistant staph
Rifamycins: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit mRNA synthesis, tuberulosis
Polyenes: synthetic or antibiotic; method of action; principle use
antibiotic, injure plasma membrane, fungicide
Grisefulvin: synthetic or antibiotic; method of action; principle use
antibiotic, inhibits mitosis, antifungals
Amantadine: synthetic or antibiotic; method of action; principle use
synthetic, block viral entry/uncoating, influenza A
Zidovudine: synthetic or antibiotic; method of action; principle use
synthetic, inhibits DNA synthesis, AIDS
Niclosamide: synthetic or antibiotic; method of action; principle use
,synthetic,inhibits oxidative phosphorylation, tapeworms
Define a chemotherapeutic agent. Distinguish between a synthetic
chemotherapeutic agent and an antibiotic
Chemotherapeutic agent: substance taken into the body to combat disease
Synthetic chemotherapeutic agent: synthesized chemically
Antibiotic: produced by a microorganism
Discuss the contributions to chemotherapy made by Ehrlich
Ehrlich: discovered the first chemotherapeutic agent
Discuss the contributions to chemotherapy made by Fleming
Fleming: discovered penicillin
Discuss the contributions to chemotherapy made by Dubos
Dubos: discovered the antibiotic gramicidin from a soil bacillus
Discuss the contributions to chemotherapy made by Waksman
Waksman: discovered the antibiotics streptomycin
List and explain five criteria used to identify an effective microbial agent
The drug should:
be selectively toxic to the microorganism
be active against many microorganisms
not produce drug resistant strains
not produce hypersensitivity to the host
not destroy the normal flora
What similar problems are encountered with antiviral, antifungal, antiprotozoan,
and antihelminthic drugs?
All of these organisms rely on eucaryotic cells. This limits the avenues of selective
toxicity
Identify three methods of action of antiviral drugs and give an example of each.
Idoxuridine and purine analogs: ex. Acyclovir
Prevent uncoating: ex. Amantadine
Activate antiviral mechanisms, like inducing nuclease which preferentially degrades viral
mRNA: ex. Interferon
Compare and contrast the broth dilution and disk diffusion tests, and identify at
least one advantage of each
Broth dilution test: a series of wells is prepared and each contains a serially diluted
concentration of the antimicrobial in broth and a standard inoculation of the test
organism. The wells are incubated 16-24 hours and observed for bacterial growth. The
minimum inhibitory concentration (MIC) is the lowest concentration of agent which
prevented growth. The lowest concentration that results in no growth upon subculture is
the minimum bactericidal concentration (MBC). Advantage: provides both MIC as well
as MBC
Agar dilution method: bacterial colonies are replicated onto nutrient media plus varying
concentrations of antimicrobial agents. The MIC is determined by measuring colony
growth. Advantage: easier and faster to perform
Describe the disk-diffusion test for microbial susceptibility. What information can
you obtain from it?
Filter paper disks impregnated with known concentrations of chemotherapeutic agents
are placed on the surface of inoculated agar plates. During incubation, the agents
, diffuse from the disks and cause zone of growth inhibition immediately surrounding the
disk.
These zones are measured and compared with a standard table to determine the extent
of test organism susceptibility to each agent
Define drug resistance. How is it produced? What can be done to minimize drug
resistance?
Drug resistance: the lack of susceptibility of a microorganism to a chemotherapeutic
agent.
It is produced initially as a result of natural selection of random mutants which happen
to be resistant to the drug. These are the only microbes which can survive in the
presence of the agent. Soon the entire population is replaced by resistance organisms.
Drug resistance can be minimized by patient compliance in taking the entire course of
medication and by using drugs in combination to reduce the chance that a resistant
organism can arise in the first place
List the advantages of using two chemotherapeutic agents simultaneously to
treat a disease. What problem can be encountered using two drugs
Advantages of using two agents in combination:
Fewer resistant strains of microorganisms develop
Some drugs act synergistically together
In the case of unknown susceptibilities, you have a better chance of effective therapy
Lower doses of each can be used, lowering the overall toxicity
Problems:
more expense involved
some antimicrobial drugs are antagonistic to each other
a wider spectrum of the normal flora will be destroyed
Why does a cell die from the following antimicrobial actions?
A) colistimethate binds to phospholipids
B) Kanamycin binds to 70s ribosomes
A) intercalation prevents normal DNA functions such as replication and transcription
B) this interferes with translation of mRNA
How is translation inhibited in each of the following:
Chloroamphenicol
Erythromycin
Tetracycline
Streptomycin
Chloramphenicol: inhibits formation of peptide bonds
Erythromycin: prevents translocation of ribosomes along
Tetracycline: interferes with attachment of tRNA to mRNA ribosome complex
Streptomycin: changes the shape of the 30S ribosome subunit, resulting in codon
misreads
Dideoxyinosine (ddI) is an antimetabolite of guanine. The 3'-OH is missing from
ddI. How does ddI inhibit DNA synthesis?
DNA polymerases add new nucleotides to the 3' OH of a growing strand. Without it,
synthesis stops
GRADED. Buy Quality Materials!
Isoniazid: synthetic or antibiotic; method of action; principle use
synthetic, vitamin B6 analog, tuberculosis
Sulfonamides: synthetic or antibiotic; method of action; principle use
synthetic, inhibit folic acid synthesis, gram-negative bacteria
Ethambutol: synthetic or antibiotic; method of action; principle use
synthetic, competitive inhibitor, tuberculosis
Trimethoprim: synthetic or antibiotic; method of action; principle use
synthetic, inhibit folic acid synthesis, Pnumocystis and UTIs
Fluoroquinolones: synthetic or antibiotic; method of action; principle use
synthetic, inhibit DNA synthesis, UTIs
Penicillin, natural: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit cell wall synthesis, gram-positive bacteria
Penicillin, synthetic: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit cell wall synthesis, broad spectrum
Cephalosporins: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit cell wall synthesis, broad spectrum
Carbapenems: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit cell wall synthesis, broad spectrum
Aminoglycosides: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit protein synthesis, gram-negative bacteria
Tetracyclines: synthetic or antibiotic; method of action; principle use
inhibit protein synthesis, broad spectrum
Chloramphenicol: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit protein synthesis, life-threatening infection
Macrolides: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit protein synthesis, gram-negative bacteria
Polypeptides: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit cell wall synthesis, injure plasma membrane, gram-positive and
negative bactiera
Vancomycin: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit cell wall synthesis, penicillin-resistant staph
Rifamycins: synthetic or antibiotic; method of action; principle use
antibiotic, inhibit mRNA synthesis, tuberulosis
Polyenes: synthetic or antibiotic; method of action; principle use
antibiotic, injure plasma membrane, fungicide
Grisefulvin: synthetic or antibiotic; method of action; principle use
antibiotic, inhibits mitosis, antifungals
Amantadine: synthetic or antibiotic; method of action; principle use
synthetic, block viral entry/uncoating, influenza A
Zidovudine: synthetic or antibiotic; method of action; principle use
synthetic, inhibits DNA synthesis, AIDS
Niclosamide: synthetic or antibiotic; method of action; principle use
,synthetic,inhibits oxidative phosphorylation, tapeworms
Define a chemotherapeutic agent. Distinguish between a synthetic
chemotherapeutic agent and an antibiotic
Chemotherapeutic agent: substance taken into the body to combat disease
Synthetic chemotherapeutic agent: synthesized chemically
Antibiotic: produced by a microorganism
Discuss the contributions to chemotherapy made by Ehrlich
Ehrlich: discovered the first chemotherapeutic agent
Discuss the contributions to chemotherapy made by Fleming
Fleming: discovered penicillin
Discuss the contributions to chemotherapy made by Dubos
Dubos: discovered the antibiotic gramicidin from a soil bacillus
Discuss the contributions to chemotherapy made by Waksman
Waksman: discovered the antibiotics streptomycin
List and explain five criteria used to identify an effective microbial agent
The drug should:
be selectively toxic to the microorganism
be active against many microorganisms
not produce drug resistant strains
not produce hypersensitivity to the host
not destroy the normal flora
What similar problems are encountered with antiviral, antifungal, antiprotozoan,
and antihelminthic drugs?
All of these organisms rely on eucaryotic cells. This limits the avenues of selective
toxicity
Identify three methods of action of antiviral drugs and give an example of each.
Idoxuridine and purine analogs: ex. Acyclovir
Prevent uncoating: ex. Amantadine
Activate antiviral mechanisms, like inducing nuclease which preferentially degrades viral
mRNA: ex. Interferon
Compare and contrast the broth dilution and disk diffusion tests, and identify at
least one advantage of each
Broth dilution test: a series of wells is prepared and each contains a serially diluted
concentration of the antimicrobial in broth and a standard inoculation of the test
organism. The wells are incubated 16-24 hours and observed for bacterial growth. The
minimum inhibitory concentration (MIC) is the lowest concentration of agent which
prevented growth. The lowest concentration that results in no growth upon subculture is
the minimum bactericidal concentration (MBC). Advantage: provides both MIC as well
as MBC
Agar dilution method: bacterial colonies are replicated onto nutrient media plus varying
concentrations of antimicrobial agents. The MIC is determined by measuring colony
growth. Advantage: easier and faster to perform
Describe the disk-diffusion test for microbial susceptibility. What information can
you obtain from it?
Filter paper disks impregnated with known concentrations of chemotherapeutic agents
are placed on the surface of inoculated agar plates. During incubation, the agents
, diffuse from the disks and cause zone of growth inhibition immediately surrounding the
disk.
These zones are measured and compared with a standard table to determine the extent
of test organism susceptibility to each agent
Define drug resistance. How is it produced? What can be done to minimize drug
resistance?
Drug resistance: the lack of susceptibility of a microorganism to a chemotherapeutic
agent.
It is produced initially as a result of natural selection of random mutants which happen
to be resistant to the drug. These are the only microbes which can survive in the
presence of the agent. Soon the entire population is replaced by resistance organisms.
Drug resistance can be minimized by patient compliance in taking the entire course of
medication and by using drugs in combination to reduce the chance that a resistant
organism can arise in the first place
List the advantages of using two chemotherapeutic agents simultaneously to
treat a disease. What problem can be encountered using two drugs
Advantages of using two agents in combination:
Fewer resistant strains of microorganisms develop
Some drugs act synergistically together
In the case of unknown susceptibilities, you have a better chance of effective therapy
Lower doses of each can be used, lowering the overall toxicity
Problems:
more expense involved
some antimicrobial drugs are antagonistic to each other
a wider spectrum of the normal flora will be destroyed
Why does a cell die from the following antimicrobial actions?
A) colistimethate binds to phospholipids
B) Kanamycin binds to 70s ribosomes
A) intercalation prevents normal DNA functions such as replication and transcription
B) this interferes with translation of mRNA
How is translation inhibited in each of the following:
Chloroamphenicol
Erythromycin
Tetracycline
Streptomycin
Chloramphenicol: inhibits formation of peptide bonds
Erythromycin: prevents translocation of ribosomes along
Tetracycline: interferes with attachment of tRNA to mRNA ribosome complex
Streptomycin: changes the shape of the 30S ribosome subunit, resulting in codon
misreads
Dideoxyinosine (ddI) is an antimetabolite of guanine. The 3'-OH is missing from
ddI. How does ddI inhibit DNA synthesis?
DNA polymerases add new nucleotides to the 3' OH of a growing strand. Without it,
synthesis stops
