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help with questions
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   Protozoan and helminthic diseases are difficult to treat because

 a. Their cells are structurally and functionally similar to human cells.
 b. They exclusively replicate inside human cells.
 c. They don't have ribosomes.
 d. They don't reproduce.
 e. They have more genes than bacteria.
    
 
2.
    Why is it difficult to find drugs that are selectively toxic when treating humans for fungal infections?

 a. Being lower eukaryotes, they do not have mitochondria.
 b. Being prokaryotes, they still have a nucleus.
 c. Being eukaryotes, they use the same mechanisms to synthesize proteins and nucleic acids.
 d. Because there are two types of fungi: molds and yeasts.
    
 
3. 
    Which of the following is a fungal component that can be exploited for selective toxicity?

 a. Cholesterol (plasma membrane)
 b. ?-glucan (cell wall)
 c. Ergosterol (plasma membrane)
 d. Amphotericin B
 e. Both b and c.
    
 
4. 
    Which of the following drugs are mismatched to their mode of action?

 a. Griseofulvin – blocks microtubule assembly
 b. imidizole, triazole, & allylamines – inhibition of ergosterol synthesis (plasma membrane becomes leaky)
 c. Flucytosine – interference of RNA synthesis, disrupting protein synthesis
 d. Echinocandins – inhibition of mitochondrial function
    r
 
5. (Points: 1) 
    Many antiviral drugs are analogs of nucleosides and nucleotides, yet eukaryotic cells can incorporate these into DNA and RNA. Why are they selectively more toxic to viruses?

 a. Comparatively, viruses undergo protein synthesis more rapidly.
 b. Because eukaryotic cells have amphibolic pathways for these analogs.
 c. Because they prevent viral attachment to the host cell.
 d. Comparatively, viruses replicate at a much higher rate thus incorporating more analogs.
    
 
6.
    How do analogs of nucleosides and nucleotides kill viruses?

 a. They accelerate the mutation rate causing the accumulation of fatal errors within the viral genome.
 b. They indirectly result in defective or missing essential viral proteins.
 c. They incorporate into the mitochondrial genome of the virus.
 d. Both b and c.
 e. Both a and b.
    
 
7.   
    All of the following are stages of the viral life cycle that can be exploited for selective toxicity of drugs EXCEPT?

 a. Viral protein cutting (processing) – prevention by protease inhibitors
 b. Integration of viral DNA into host’s DNA – prevention by integrase inhibitors
 c. Viral synthesis of plasma membrane – prevention by antibiotics
 d. Viral entry into host cell – prevention by fusion inhibitors
    Save Answer
 
8. (
    Match the following antiviral drugs to their mode of action:
Column preview
1. Tamiflu   a. nucleoside analog
2. Tenofovir   b. reverse transcriptase inhibitor of HIV
3. Indinavir   c. protease inhibitor
4. Acyclovir   d. induction of antiviral interferons
5. Imiquimod   e. inhibition of influenza virus neuraminidase

Matching pairs
1      
2      
3      
4      
5      
    
 
9.   
    Malaria is a protozoan disease caused by species of the genera Plasmodium. All of the following are drugs used to treat malaria EXCEPT?

 a. Quinacrine
 b. Tinidazole
 c. Quinine
 d. Mefloquine
    
 
10. 
    Some protozoans like Trichomonas vaginalis undergo anaerobic metabolism like strictly anaerobic bacteria such as Clostridium. Which of the following is a drug that can interfere with anaerobic metabolism?

 a. Metronidazole
 b. Nitazoxanide
 c. Albendazole
 d. Ivermectin
    
 
11. 
    All of the following are modes of action of antihelminthic drugs EXCEPT?

 a. inhibition of cytoplasmic microtubule formation
 b. inhibition of attachment to host
 c. inhibition of ATP production under aerobic conditions
 d. alteration of plasma membrane permeability
    
 
12.
    Which of the following are tests for microbial sensitivity to chemotherapeutic agents?

 a. Broth dilution
 b. Kirby-Bauer disk-diffusion
 c. Vogues-Prauskaeur
 d. Both a & b
 e. Both b and c
    
 
13. ) 
    Why does the zone of inhibition around a disk on a Kirby-Bauer plate vary with the antibiotic?

 a. Some antibiotic disks undergo osmosis.
 b. Some antibiotics are chemotactant.
 c. Some antibiotics have poor solubilities and cannot diffuse outward into the plate easily.
 d. None of the above.
    
 
14.
    What advantage does the broth dilution test hold over the disk-diffusion method?

 a. It can determine the minimal bactericidal concentration (MBC)
 b. It can determine the minimal inhibitory concentration (MIC)
 c. Both a and b.
 d. None of the above.
    
 
15.
    
Table 20.1

The following data were obtained from a broth dilution test.

 

Concentration of Antibiotic X
Growth
Growth in
Subculture
2 ?g/ml
+
+
10 ?g/ml
-
+
15 ?g/ml
-
-
25 ?g/ml
-
-

 
In Table 20.1, the minimal bactericidal concentration of antibiotic X is

 a. 2 ?g/ml
 b. 10 ?g/ml
 c. 15 ?g/ml
 d. 25 ?g/ml
 e. Can't tell.
    
 
16.
    In Table 20.1, the minimal inhibitory concentration of antibiotic X is

 a. 2 ?g/ml
 b. 10 ?g/ml
 c. 15 ?g/ml
 d. 25 ?g/ml
 e. Can't tell.


17-Assume you have isolated an unknown virus. It is a single-stranded RNA, enveloped virus. To which group does it most likely belong?

 a. Herpesvirus
 b. Picornavirus
 c. Retrovirus
 d. Togavirus
 e. Papovavirus
    Save Answer
 
18-
    To which group does a small, nonenveloped single-stranded RNA virus most likely belong?

 a. Herpesvirus
 b. Picornavirus
 c. Retrovirus
 d. Togavirus
 e. Papovavirus
    
 
19- 
    Viruses that have reverse transcriptase are in the

 a. Retroviridae and Picornaviridae.
 b. Herpesviridae and Retroviridae.
 c. Hepadnaviridae and Retroviridae.
 d. Bacteriophage families.
 e. Influenzavirus.
    
 
20-
    Approximately how many virus particles, 333nm each, could fit along a 1-millimeter line?

 a. 3
 b. 30
 c. 300
 d. 3,000
 e. 30,000
    
 
21- 
    Which one of the following steps does NOT occur during multiplication of a picornavirus?

 a. Synthesis of + strands of RNA
 b. Synthesis of - strands of RNA
 c. Synthesis of viral proteins
 d. Synthesis of DNA
 e. None of the above
    
 
22-
    All of the following viruses can cause cancer in animals EXCEPT?

 a. Hepatitis C
 b. Hepatitis B
 c. Oncovirus
 d. Mastadenovirus
 e. Herpesvirus 4 (Epstein-Barr virus)
    
 
23-
    This family of viruses cause warts, polyomas, and vacuolation.

 a. Poxviridae
 b. Caliciviridae
 c. Filoviridae
 d. Reoviridae
 e. Papovaviridae
    
24- 
    These viruses are responsible for fever blisters (cold sores) and can be transmitted via oral and genital routes.

 a. Roseolavirus (HHV-6) & Kaposi’s sarcoma virus (HHV-8)
 b. Hepatitis A & Hepatitis E viruses
 c. Flavivirus & Hepatitis C virus
 d. Herpes Simplex viruses 1 and 2
    
 
25-
    Human Herpesvirus 4 is unusual because:

 a. it is transmitted in body secretions such as breast milk and semen.
 b. it is transmitted by an arthropod vector (tick).
 c. it is responsible for causing at least two different diseases (Burkitt’s lymphoma & infectious mononucleosis).
 d. it causes cells to enlarge and acquire inclusion bodies.
    
26- 
    What do yellow fever, dengue, eastern & western equine encephalitis, and West Nile virus encephalitis all have in common?

 a. They are all viral diseases of humans that are transmitted by ticks.
 b. They are all viral diseases of humans that are transmitted by mosquitoes.
 c. They are all viral diseases of humans that are considered to be new & emerging (EIDs).
 d. All of the above.
 e. None of the above.
    
 
27-
    Viruses like Marburg and Ebola cause fever and profuse bleeding from all orifices in humans. What is the term used to describe diseases caused by these viruses?

 a. Arboviral Encephalitis
 b. Cytomegaly
 c. Cold sore / fever blister
 d. Viral Variola
 e. Viral Hemorrhagic Fevers
    
 
28- 
    The Lyssavirus, family Rhabdoviridae, is the causitve agent of rabies. Which of the following is true about this virus?

 a. It is unique in that its incubation period is usually long enough to allow immunity to develop from post-exposure vaccination.
 b. Mutant strains develop rapidly because it is a single-stranded RNA virus with no proofreading capability.
 c. It is usually transmitted through the bite of an infected animal.
 d. The virus proliferates in the peripheral nervous system and moves fatally to the central nervous system.
 e. All of the above.
    
 
29-
    What virus causes the majority of cases of the common cold?

 a. Coronavirus
 b. Influenzavirus
 c. Rubivirus
 d. Rhinovirus
    Save Answer
 
30-
    What is the virus that is frequently in the news, is associated with large gatherings that have food, causes acute gastroenteritis with vomiting and/or diarrhea, and is transmitted via a fecal-oral route from food, water, or vomitus aerosols?

 a. Norovirus
 b. Hepatitis B
 c. Rubulavirus (mumps)
 d. Coronavirus (severe acute respiratory syndrome – SARS virus)
    
 
31- 
    Why are the retroviruses unique among RNA viruses?

 a. They copy their RNA genome into double-stranded DNA using reverse transcriptase.
 b. Their genome consists of 8 different (-) strands of RNA.
 c. They use viral integrase to incorporate their newly made double-stranded DNA into the host cell chromosome.
 d. Both A and B.
 e. Both A and C.

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Reply# 1
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Posts: 12846
Points: 12141
Rep:  +716  -2 
4 years ago

 Protozoan and helminthic diseases are difficult to treat because

 a. Their cells are structurally and functionally similar to human cells.

 b. They exclusively replicate inside human cells.
 c. They don't have ribosomes.
 d. They don't reproduce.
 e. They have more genes than bacteria.
     
 
2.
    Why is it difficult to find drugs that are selectively toxic when treating humans for fungal infections?

 a. Being lower eukaryotes, they do not have mitochondria.
 b. Being prokaryotes, they still have a nucleus.
 c. Being eukaryotes, they use the same mechanisms to synthesize proteins and nucleic acids.
 d. Because there are two types of fungi: molds and yeasts.
     
 
3. 
    Which of the following is a fungal component that can be exploited for selective toxicity?

 a. Cholesterol (plasma membrane)
b. ?-glucan (cell wall)
 c. Ergosterol (plasma membrane)
 d. Amphotericin B
 e. Both b and c.



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Reply# 2
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Posts: 1020
Points: 3416
Rep:  +78  -0 
4 years ago

n Table 20.1, the minimal bactericidal concentration of antibiotic X is

a. 2 ?g/ml
 b. 10 ?g/ml
 c. 15 ?g/ml
 d. 25 ?g/ml
 e. Can't tell.
     
 
16.
    In Table 20.1, the minimal inhibitory concentration of antibiotic X is

 a. 2 ?g/ml
b. 10 ?g/ml
 c. 15 ?g/ml
 d. 25 ?g/ml
 e. Can't tell.


17-Assume you have isolated an unknown virus. It is a single-stranded RNA, enveloped virus. To which group does it most likely belong?

 a. Herpesvirus
 b. Picornavirus
 c. Retrovirus
 d. Togavirus
 e. Papovavirus
    Save Answer
 
18-
    To which group does a small, nonenveloped single-stranded RNA virus most likely belong?

 a. Herpesvirus
b. Picornavirus
 c. Retrovirus
 d. Togavirus
 e. Papovavirus
   
 
19- 
    Viruses that have reverse transcriptase are in the

 a. Retroviridae and Picornaviridae.
 b. Herpesviridae and Retroviridae.
c. Hepadnaviridae and Retroviridae.
 d. Bacteriophage families.
 e. Influenzavirus.
   
 
20-
    Approximately how many virus particles, 333nm each, could fit along a 1-millimeter line?

 a. 3
 b. 30
 c. 300
 d. 3,000
 e. 30,000
   
 
21- 
    Which one of the following steps does NOT occur during multiplication of a picornavirus?

 a. Synthesis of + strands of RNA
 b. Synthesis of - strands of RNA
 c. Synthesis of viral proteins
 d. Synthesis of DNA
 e. None of the above



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