The Hardest Microbiology Questions And Answers! Quiz

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The Hardest Microbiology Questions And Answers! Quiz - Quiz

The study of microbiology has made a significant impact on the medical industry, and there are a lot of things that one can learn through it and come up with solutions to some of the issues we are facing with some illnesses. Do you think you have what it takes to tackle the hardest microbiology exam? Take up the quiz below and get to find out!


Questions and Answers
  • 1. 

    Who is usually credited with the discovery of penicillin?  

    • A.

      Fleming

    • B.

      Florey and Chain

    • C.

      Duchesne

    • D.

      Ehrlich

    Correct Answer
    A. Fleming
    Explanation
    Fleming is usually credited with the discovery of penicillin.

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  • 2. 

    Whose discovery of streptomycin stimulated an intense search for other antibiotics?  

    • A.

      Waksman

    • B.

      Ehrlich

    • C.

      Fleming

    • D.

      Pasteur

    Correct Answer
    A. Waksman
    Explanation
    Waksman's discovery of streptomycin stimulated an intense search for other antibiotics. Streptomycin was the first effective treatment for tuberculosis, and its discovery revolutionized the field of antibiotics. This breakthrough led to a renewed focus on the search for other antibiotics, as scientists realized the potential for these drugs to combat various bacterial infections. Waksman's work paved the way for the development of many other life-saving antibiotics.

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  • 3. 

    The use of arsenic compound Salvarsan as a treatment for syphilis is credited to  

    • A.

      Fleming

    • B.

      Ehrlich

    • C.

      Waksman

    • D.

      Chain

    Correct Answer
    B. Ehrlich
    Explanation
    The correct answer is Ehrlich. Paul Ehrlich is credited with the use of the arsenic compound Salvarsan as a treatment for syphilis. He developed the drug in 1909 and it was the first effective treatment for syphilis. Ehrlich's work on Salvarsan marked a significant advancement in the treatment of infectious diseases and earned him a Nobel Prize in Physiology or Medicine in 1908.

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  • 4. 

    Chemotherapeutic agents that are natural products of microorganisms are most specifically referred to as __________.  

    • A.

      Antimicrobial agents


    • B.

      Synthetic drugs

    • C.

      Antibiotics

    • D.

      Semisynthetic drugs

    Correct Answer
    C. Antibiotics
    Explanation
    Antibiotics are chemotherapeutic agents that are natural products of microorganisms. They are specifically designed to target and kill bacteria or inhibit their growth. Antibiotics are not synthetic drugs, which are chemically synthesized in a laboratory. They are also different from semisynthetic drugs, which are derived from natural sources but are chemically modified to enhance their effectiveness. Therefore, the correct answer is antibiotics.

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  • 5. 

    Who is generally credited with the discovery of sulfanilamide as a chemotherapeutic agent?  

    • A.

       Gerhard Domagk

    • B.

      Ernest Duchesne

    • C.

      Ernst Chain

    • D.

       Robert Koch

    Correct Answer
    A.  Gerhard Domagk
    Explanation
    Gerhard Domagk is generally credited with the discovery of sulfanilamide as a chemotherapeutic agent. Domagk was a German pathologist and bacteriologist who conducted extensive research on the antimicrobial properties of dyes. In the 1930s, he discovered that a red dye called prontosil was effective in treating infections caused by streptococcal bacteria. This led to the development of sulfanilamide, the first commercially available antibiotic. Domagk's discovery revolutionized the field of medicine and opened up new possibilities for the treatment of bacterial infections.

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  • 6. 

    ________ __________ are activities of a chemotherapeutic agent that damage the host either by inhibiting the same process in the host as in the target cell or by damaging other processes. (2 words)  

    Correct Answer
    Side effects
    Explanation
    The activities of a chemotherapeutic agent that damage the host either by inhibiting the same process in the host as in the target cell or by damaging other processes are referred to as side effects. These can include various negative effects on the body, such as nausea, hair loss, and weakened immune system, among others.

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  • 7. 

     The minimum lethal concentration (MLC) is the lowest concentration of drug from which organisms fail to recover when removed from the drug.  

    • A.

      True

    • B.

      False

    Correct Answer
    A. True
    Explanation
    The explanation for the given correct answer is that the minimum lethal concentration (MLC) refers to the lowest concentration of a drug that causes organisms to be unable to recover when they are taken out of the drug's presence. This means that even after the organisms are removed from the drug, they are unable to survive or recover from the effects of the drug. Therefore, the statement is true.

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  • 8. 

    Agents that are static and, therefore, do not kill infecting microorganisms are not useful as chemotherapeutic agents.  

    • A.

      True

    • B.

      False

    Correct Answer
    B. False
    Explanation
    Agents that are static and do not kill infecting microorganisms may still be useful as chemotherapeutic agents. While killing microorganisms is a common mechanism of action for many chemotherapeutic agents, static agents can also be effective in controlling infections by inhibiting the growth and reproduction of microorganisms. Therefore, the statement is false.

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  • 9. 

    A drug that disrupts a microbial function not found in animal cells usually has a higher therapeutic index.  

    • A.

      True

    • B.

      False

    Correct Answer
    A. True
    Explanation
    A drug that disrupts a microbial function not found in animal cells usually has a higher therapeutic index because it specifically targets the microbes without affecting the normal functioning of animal cells. This selectivity allows for a higher concentration of the drug to be used to effectively kill or inhibit the growth of the microbes, while minimizing the potential for toxicity or harm to the animal cells. As a result, the therapeutic index, which is the ratio of the dose that produces therapeutic effects to the dose that produces toxic effects, is higher for drugs that target microbial functions not found in animal cells.

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  • 10. 

    The drug level required for the clinical treatment of a particular infection is called the  

    • A.

      Therapeutic dose.


    • B.

      Toxic dose.

    • C.

      Therapeutic index.


    • D.

      Minimal inhibitory concentration.

    Correct Answer
    A. Therapeutic dose.

    Explanation
    The therapeutic dose refers to the drug level that is necessary for the effective treatment of a specific infection. This dose is carefully determined to ensure that it is neither too low to be effective nor too high to cause toxicity. The toxic dose, on the other hand, refers to the drug level that can cause harmful or adverse effects. The therapeutic index is a measure of the safety of a drug and is calculated by dividing the toxic dose by the therapeutic dose. The minimal inhibitory concentration is the lowest concentration of a drug that can inhibit the growth of a particular microorganism.

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  • 11. 

    Which of the following inhibits protein synthesis?  

    • A.

      Dapsone

    • B.

      Erythromycin

    • C.

      Penicillin

    • D.

      Isoniazid

    Correct Answer
    B. Erythromycin
    Explanation
    Erythromycin inhibits protein synthesis. Erythromycin is a macrolide antibiotic that works by binding to the 50S subunit of the bacterial ribosome, thereby blocking the translocation step of protein synthesis. This prevents the elongation of the growing peptide chain and ultimately inhibits bacterial protein synthesis.

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  • 12. 

    Which of the following is likely to have the most toxic side effects to humans?  

    • A.

      inhibitors of cell wall synthesis

    • B.

        inhibitors of protein synthesis 


    • C.

      disrupters of cell membrane structure 


    • D.

      Inhibitors of DNA synthesis

    Correct Answer
    C. disrupters of cell membrane structure 

    Explanation
    Disrupters of cell membrane structure are likely to have the most toxic side effects to humans because the cell membrane is responsible for regulating the passage of substances in and out of the cell. Disrupting the cell membrane structure can lead to the loss of important cellular functions and can cause severe damage to the cell and surrounding tissues. This can result in a wide range of toxic effects on the human body. Inhibitors of cell wall synthesis, protein synthesis, and DNA synthesis may also have toxic effects, but disrupting the cell membrane structure is more likely to have the most severe and immediate impact.

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  • 13. 

     Isoniazid is a narrow-spectrum antibiotic that  

    • A.

      Is not useful as a chemotherapeutic agent.

    • B.

      Is one of the few drugs effective against Mycobacterium tuberculosis.

    • C.

       is one of the few drugs effective against systemic fungal infections.


    • D.

      None of the choices

    Correct Answer
    B. Is one of the few drugs effective against Mycobacterium tuberculosis.
    Explanation
    Isoniazid is a narrow-spectrum antibiotic that is specifically effective against Mycobacterium tuberculosis, the bacterium that causes tuberculosis. It is considered one of the few drugs that can effectively treat tuberculosis infections.

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  • 14. 

    Consider an antibacterial drug. In which of the following cases would the action of the drug be considered primarily bacteriostatic?  

    • A.

      The minimal lethal concentration (MLC) is equal to the minimal inhibitory concentration (MIC).

    • B.

      The MLC is lower than the MIC.

    • C.

      The MLC is 2-4 times higher than the MIC.

    • D.

      The MLC is 10-20 times higher than the MIC.

    Correct Answer
    D. The MLC is 10-20 times higher than the MIC.
  • 15. 

    Chemotherapeutic agents that are chemically modified natural products of microorganisms are most specifically referred to as __________.  

    • A.

      Antimicrobial agents


    • B.

      Synthetic drugs


    • C.

      Antibiotics


    • D.

       semisynthetic drugs

    Correct Answer
    D.  semisynthetic drugs
    Explanation
    Semisynthetic drugs are chemotherapeutic agents that are chemically modified natural products of microorganisms. They are created by modifying the structure of naturally occurring compounds to enhance their efficacy or reduce their toxicity. This process involves chemical modifications such as adding or removing functional groups or substituting specific atoms in the molecule. These modifications can improve the drug's pharmacokinetics, increase its spectrum of activity, or overcome resistance mechanisms. Therefore, semisynthetic drugs are the most specific term for chemotherapeutic agents that are chemically modified natural products of microorganisms.

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  • 16. 

    Chemotherapeutic agents that are artificially produced are most specifically referred to as __________.  

    • A.

      Antimicrobial agents


    • B.

      Synthetic drugs

    • C.

      Antibiotics

    • D.

      Semisynthetic drugs

    Correct Answer
    B. Synthetic drugs
    Explanation
    Synthetic drugs are chemotherapeutic agents that are artificially produced. This term specifically refers to drugs that are created in a laboratory using chemical synthesis techniques rather than being derived from natural sources. These drugs are designed to have specific therapeutic effects and are often used to treat various diseases and conditions. Examples of synthetic drugs include aspirin, ibuprofen, and chemotherapy drugs used to treat cancer.

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  • 17. 

    The ratio of toxic dose to therapeutic dose is called the  

    • A.

      Toxicity index.

    • B.

      Phenol coefficient.


    • C.

      Therapeutic index.

    • D.

      Susceptibility quotient.

    Correct Answer
    C. Therapeutic index.
    Explanation
    The therapeutic index is the ratio of the toxic dose to the therapeutic dose of a drug. It is used to measure the safety and effectiveness of a drug, as a higher therapeutic index indicates a wider margin of safety. The toxic dose is the amount of a drug that causes harmful effects, while the therapeutic dose is the amount needed to produce a desired therapeutic effect. Therefore, the therapeutic index provides a measure of the drug's safety by comparing the amount needed for therapeutic benefits to the amount that could potentially cause harm.

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  • 18. 

    The minimal lethal concentration (MLC) is the  

    • A.

      lowest concentration of a drug that prevents growth of a particular pathogen.

    • B.

      Highest concentration of a drug that prevents growth of a particular pathogen.

    • C.

      Lowest concentration of a drug that kills a particular pathogen.

    • D.

      Highest concentration of a drug that kills a particular pathogen.

    Correct Answer
    C. Lowest concentration of a drug that kills a particular pathogen.
    Explanation
    The minimal lethal concentration (MLC) refers to the lowest concentration of a drug that is required to kill a particular pathogen. This means that at concentrations below the MLC, the drug may still inhibit the growth of the pathogen but not necessarily kill it. Therefore, the MLC is the lowest concentration necessary to achieve a lethal effect on the pathogen.

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  • 19. 

     The lowest concentration of an antibiotic that prevents growth is the  

    • A.

      Minimal inhibitory concentration (MIC). 


    • B.

      Minimal lethal concentration (MLC). 


    • C.

      50% inhibitory dose.

    • D.

      All of the choices

    Correct Answer
    A. Minimal inhibitory concentration (MIC). 

    Explanation
    The lowest concentration of an antibiotic that prevents growth is known as the minimal inhibitory concentration (MIC). This is the concentration at which the antibiotic is still able to inhibit the growth of the microorganism, but not kill it. The minimal lethal concentration (MLC) refers to the lowest concentration that is able to kill the microorganism. The 50% inhibitory dose is not a term commonly used in relation to antibiotics. Therefore, the correct answer is minimal inhibitory concentration (MIC).

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  • 20. 

    Which of the following is a desirable general characteristic of antimicrobial drugs?  

    • A.

       selective toxicity


    • B.

      Broad-spectrum of activity


    • C.

      Bactericidal rather than bacteriostatic

    • D.

      All of the choices

    Correct Answer
    D. All of the choices
    Explanation
    All of the choices are desirable general characteristics of antimicrobial drugs. Selective toxicity refers to the ability of a drug to selectively target and kill harmful microorganisms without causing significant harm to the host. Broad-spectrum of activity means that the drug is effective against a wide range of microorganisms. Bactericidal drugs kill bacteria directly, while bacteriostatic drugs inhibit their growth and reproduction. Having all of these characteristics in an antimicrobial drug would make it highly effective in treating various infections.

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  • 21. 

    When a chemotherapeutic agent is effective against many different pathogens, it is said to be a __________ antibiotic.  (2 words)  

    Correct Answer
    broad-spectrum
    broad spectrum
    Explanation
    A chemotherapeutic agent that is effective against many different pathogens is referred to as a broad-spectrum antibiotic. This means that it can target and kill a wide range of bacteria or other microorganisms, making it useful in treating a variety of infections.

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  • 22. 

     In a disk diffusion assay for drug susceptibility, a drug producing a larger clear zone is always more effective than a drug than to one producing a smaller clear zone.  

    • A.

      True

    • B.

      False

    Correct Answer
    B. False
    Explanation
    The statement is false because the size of the clear zone in a disk diffusion assay does not necessarily indicate the effectiveness of a drug. The clear zone represents the inhibition of bacterial growth around the drug, but it does not provide information about the minimum inhibitory concentration (MIC) required to effectively treat an infection. A drug with a smaller clear zone may still be effective if it has a lower MIC. Therefore, the size of the clear zone alone cannot determine the effectiveness of a drug.

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  • 23. 

    Which of the following affects the size of the clear zone in a disk diffusion test of antimicrobial susceptibility?  

    • A.

       the initial concentration of the drug


    • B.

       the solubility of the drug


    • C.

      The diffusion rate of the drug

    • D.

      All of the choices

    Correct Answer
    D. All of the choices
    Explanation
    All of the choices affect the size of the clear zone in a disk diffusion test of antimicrobial susceptibility. The initial concentration of the drug determines the amount of drug available to diffuse into the surrounding medium. The solubility of the drug affects how readily it can dissolve and diffuse from the disk. The diffusion rate of the drug determines how quickly it can spread through the medium. Therefore, all of these factors contribute to the size of the clear zone.

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  • 24. 

    The E test is  

    • A.

      A rapid serological test used to detect the presence of eastern equine encephalitis virus in cerebrospinal fluid.

    • B.

      A quantitative antibiotic sensitivity test that utilizes plastic strips impregnated with an antibiotic of interest.

    • C.

      Used to quantify levels of IgE antibody in serum samples. 


    • D.

      Used to measure esculine levels in pasteurized milk.

    Correct Answer
    B. A quantitative antibiotic sensitivity test that utilizes plastic strips impregnated with an antibiotic of interest.
  • 25. 

    In the broth dilution test, the highest concentration of the antibiotic resulting in no growth after 16 to 20 hours of incubation is the MIC.  

    • A.

      True

    • B.

      False

    Correct Answer
    B. False
    Explanation
    The given statement is false. In the broth dilution test, the lowest concentration of the antibiotic that inhibits visible growth after 16 to 20 hours of incubation is the MIC (Minimum Inhibitory Concentration). The MIC is the lowest concentration at which the antibiotic is still effective in inhibiting the growth of the microorganism being tested.

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  • 26. 

    Which of the following is not true about Kirby-Bauer disk diffusion method?  

    • A.

      After inoculation of bacteria, the agar surface is dried for about 5 minutes and the appropriate antibiotic test disks are placed on it.

    • B.

      The plate is placed at 35C for 16 to 18 hours of incubation. 


    • C.

      Bacteria used to swab plate should be at least a week old.  

    • D.

      The diameters of the zones of inhibition are measured to the nearest millimeter.

    Correct Answer
    C. Bacteria used to swab plate should be at least a week old.  
    Explanation
    The Kirby-Bauer disk diffusion method is a technique used to determine the susceptibility of bacteria to antibiotics. The method involves inoculating bacteria onto an agar plate, placing antibiotic disks on the plate, and incubating it for a specific period of time. The diameters of the zones of inhibition around the disks are then measured to determine the effectiveness of the antibiotics. However, it is not true that the bacteria used to swab the plate should be at least a week old. The age of the bacteria is not a factor in this method.

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  • 27. 

    Which of the following does not inhibit protein synthesis?  

    • A.

      Tetracycline

    • B.

      Streptomycin

    • C.

      Erythromycin

    • D.

      Penicillin

    • E.

      All of the choices inhibit protein synthesis

    Correct Answer
    D. Penicillin
    Explanation
    Penicillin does not inhibit protein synthesis. Penicillin is an antibiotic that works by interfering with the synthesis of the bacterial cell wall, not by inhibiting protein synthesis. It targets the enzymes involved in cell wall synthesis, weakening the cell wall and causing the bacteria to burst. Therefore, penicillin is not involved in inhibiting protein synthesis.

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  • 28. 

     The most selective antibacterial agents are those that interfere with bacterial cell wall synthesis. This is because  

    • A.

      Bacterial cell walls have a unique structure not found in eukaryotic host cells.

    • B.

      Bacterial cell wall synthesis is easily inhibited whereas eukaryotic cell wall synthesis is more resistant to the actions of the drugs. 


    • C.

      Eukaryotic cells do not take up the drugs. 


    • D.

      eukaryotic cells inactivate the drugs before they can do any damage.

    Correct Answer
    A. Bacterial cell walls have a unique structure not found in eukaryotic host cells.
    Explanation
    The most selective antibacterial agents are those that interfere with bacterial cell wall synthesis because bacterial cell walls have a unique structure not found in eukaryotic host cells. This means that drugs targeting bacterial cell wall synthesis are more likely to specifically affect bacteria and not harm the host cells.

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  • 29. 

    In addition to inhibiting the transpeptidation reaction in cell wall synthesis, penicillins may also destroy bacteria by  

    • A.

      inhibiting DNA replication.

    • B.

      Stimulating proteins to form holes in the plasma membrane. 


    • C.

      inhibiting protein synthesis.

    • D.

      none of the choices

    Correct Answer
    B. Stimulating proteins to form holes in the plasma membrane. 

    Explanation
    Penicillins may destroy bacteria by stimulating proteins to form holes in the plasma membrane. This can disrupt the integrity of the bacterial cell membrane, leading to leakage of cellular contents and ultimately cell death. In addition to inhibiting the transpeptidation reaction in cell wall synthesis, this mechanism of action further contributes to the antibacterial effects of penicillins.

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  • 30. 

    It is difficult to treat central nervous system infections because  

    • A.

      the organisms causing such infections are usually resistant to most drugs.

    • B.

      It is difficult for many drugs to penetrate the blood-brain barrier. 


    • C.

      Most infections of the central nervous system are caused by fungi.

    • D.

      toxic side effects can result in severe neurological damage.

    Correct Answer
    B. It is difficult for many drugs to penetrate the blood-brain barrier. 

    Explanation
    Central nervous system infections are difficult to treat because many drugs are unable to penetrate the blood-brain barrier. The blood-brain barrier is a protective mechanism that prevents harmful substances from entering the brain and spinal cord. However, this barrier also prevents many drugs from reaching the site of infection in the central nervous system. Therefore, finding effective treatments for these infections can be challenging.

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  • 31. 

    Aminoglycoside antibiotics  

    • A.

       inhibit cell wall synthesis.


    • B.

      Inhibit folic acid biosynthesis.


    • C.

      Bind to the 30S ribosomal subunit.


    • D.

      Bind to bacterial DNA polymerase.

    Correct Answer
    C. Bind to the 30S ribosomal subunit.

    Explanation
    Aminoglycoside antibiotics bind to the 30S ribosomal subunit. This binding prevents the ribosome from properly reading the genetic code and synthesizing proteins, ultimately inhibiting bacterial protein synthesis. By targeting the ribosome, aminoglycosides disrupt bacterial growth and replication, making them effective antibiotics against a wide range of bacterial infections.

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  • 32. 

    Sulfonamides and other drugs that inhibit folic acid synthesis have a high therapeutic index because  

    • A.

      Humans do not use folic acid.


    • B.

      Humans do not synthesize folic acid but obtain it in their diets.


    • C.

      Humans synthesize folic acid by a process that is not sensitive to sulfonamides.


    • D.

      None of these

    Correct Answer
    B. Humans do not synthesize folic acid but obtain it in their diets.

    Explanation
    Sulfonamides and other drugs that inhibit folic acid synthesis have a high therapeutic index because humans do not synthesize folic acid but obtain it in their diets. This means that these drugs can selectively target and inhibit the folic acid synthesis in bacteria or other pathogens without affecting the folic acid metabolism in humans. Since humans obtain folic acid from their diet, the inhibition of its synthesis in pathogens does not have a significant impact on human health, making these drugs effective and safe for human use.

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  • 33. 

    Antibiotics that are given by injection are said to have a(n) __________ route of administration.  

    • A.

      Oral

    • B.

      Venal

    • C.

      Parenteral

    • D.

      Topical

    Correct Answer
    C. Parenteral
    Explanation
    Antibiotics that are given by injection are said to have a parenteral route of administration. Parenteral refers to any route of administration that does not involve the digestive tract, such as injection into the bloodstream or tissues. This method allows for direct delivery of the medication into the body, bypassing the need for absorption through the gastrointestinal system.

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  • 34. 

    Sulfonamides inhibit the production of folic acid and, therefore, inhibit the synthesis of __________.  

    • A.

      Purines and pyrimidines

    • B.

      Ribose

    • C.

      Aromatic amino acids

    • D.

      Peptidoglycan

    Correct Answer
    A. Purines and pyrimidines
    Explanation
    Sulfonamides are a class of antibiotics that work by inhibiting the production of folic acid. Folic acid is essential for the synthesis of purines and pyrimidines, which are the building blocks of DNA and RNA. Therefore, when sulfonamides inhibit folic acid production, they also inhibit the synthesis of purines and pyrimidines. This ultimately disrupts the replication and growth of bacteria, making sulfonamides effective in treating bacterial infections.

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  • 35. 

    Which of the following is (are) true about cephalosporins?  

    • A.

      They, like penicillin, inhibit bacterial cell wall synthesis. 


    • B.

      There are four generations of cephalosporins.

    • C.

      They can be given to patients with penicillin allergies. 


    • D.

      All of the choices

    Correct Answer
    D. All of the choices
    Explanation
    Cephalosporins are a class of antibiotics that inhibit bacterial cell wall synthesis, similar to penicillin. There are indeed four generations of cephalosporins, each with different spectra of activity. One advantage of cephalosporins is that they can be given to patients with penicillin allergies, making them a suitable alternative for these individuals. Therefore, all of the choices are true about cephalosporins.

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  • 36. 

    Bacitracin  

    • A.

      inhibits DNA replication. 


    • B.

      inhibits peptidoglycan synthesis. 


    • C.

      interferes with protein synthesis.

    • D.

      interferes with plasma membrane function.

    Correct Answer
    B. inhibits peptidoglycan synthesis. 

    Explanation
    Bacitracin is an antibiotic that specifically targets the synthesis of peptidoglycan, a major component of bacterial cell walls. By inhibiting peptidoglycan synthesis, bacitracin weakens the cell wall and prevents the formation of a strong and protective barrier. This ultimately leads to the lysis and death of the bacteria. Bacitracin does not directly affect DNA replication, protein synthesis, or plasma membrane function. Therefore, the correct answer is that bacitracin inhibits peptidoglycan synthesis.

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  • 37. 

    Vancomycin  

    • A.

      Inhibits the transglycosylase reaction in peptidoglycan biosynthesis.

    • B.

      Interferes with the action of the lipid carrier that transports peptidoglycan precursors across the plasma membrane.

    • C.

      Inhibits the transpeptidation reaction in peptidoglycan biosynthesis.


    • D.

      Blocks the addition of the pentapeptide chain during peptidoglycan biosynthesis.

    Correct Answer
    C. Inhibits the transpeptidation reaction in peptidoglycan biosynthesis.

    Explanation
    Vancomycin is a medication that inhibits the transpeptidation reaction in peptidoglycan biosynthesis. This means that it prevents the cross-linking of the peptidoglycan chains, which are important for the structural integrity of bacterial cell walls. By inhibiting this reaction, Vancomycin weakens the cell wall and makes the bacteria more susceptible to damage and destruction. This mechanism of action makes Vancomycin an effective antibiotic against certain bacteria.

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  • 38. 

    Which of the following is a useful mechanism of action for an antibacterial drug?  

    • A.

      Inhibition of cell wall synthesis

    • B.

      Inhibition of protein synthesis

    • C.

       interference with RNA and DNA synthesis


    • D.

      All of the choices

    Correct Answer
    D. All of the choices
    Explanation
    All of the choices are useful mechanisms of action for an antibacterial drug. Inhibition of cell wall synthesis prevents bacteria from forming a protective barrier, making them more susceptible to destruction. Inhibition of protein synthesis disrupts the production of essential proteins in bacteria, hindering their growth and survival. Interference with RNA and DNA synthesis prevents bacteria from replicating and transcribing genetic information, ultimately leading to their death. Therefore, all of these mechanisms are effective in combating bacterial infections.

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  • 39. 

    Which of the following antibiotics specifically inhibits DNA synthesis?  

    • A.

      Gentamycin

    • B.

      Polymyxin B


    • C.

      Quinolones

    • D.

      Tetracycline

    Correct Answer
    C. Quinolones
    Explanation
    Quinolones specifically inhibit DNA synthesis. They do this by targeting and inhibiting the enzyme DNA gyrase, which is responsible for the supercoiling of DNA during replication. By inhibiting DNA gyrase, quinolones prevent the proper replication and transcription of DNA, ultimately leading to the inhibition of bacterial growth. Gentamycin, polymyxin B, and tetracycline do not specifically inhibit DNA synthesis, making quinolones the correct answer.

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  • 40. 

    Protein synthesis inhibitors have a low therapeutic index because they usually cannot discriminate between prokaryotic and eukaryotic ribosomes.  

    • A.

      True

    • B.

      False

    Correct Answer
    B. False
    Explanation
    Protein synthesis inhibitors have a low therapeutic index because they usually cannot discriminate between prokaryotic and eukaryotic ribosomes. This statement is false. Protein synthesis inhibitors actually have a high therapeutic index because they can selectively target prokaryotic ribosomes, which are different from eukaryotic ribosomes. This allows for the inhibition of bacterial protein synthesis without affecting the protein synthesis in human cells, leading to a more specific and effective treatment for bacterial infections.

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  • 41. 

    Ampicillin, like penicillin, must be administered by injection because it is rapidly degraded in the stomach and cannot, therefore, be given orally.  

    • A.

      True

    • B.

      False

    Correct Answer
    B. False
    Explanation
    Ampicillin, unlike penicillin, can be administered orally because it is not rapidly degraded in the stomach.

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  • 42. 

    A(n) __________ is a drug that blocks the function of a metabolic pathway.  

    Correct Answer
    antimetabolite
    Explanation
    An antimetabolite is a drug that interferes with the normal functioning of a metabolic pathway. It structurally resembles a metabolite that is required for the pathway, but when it is incorporated into the pathway, it disrupts its normal function. This disruption can inhibit the growth or replication of cells that rely on the metabolic pathway, making antimetabolites useful in the treatment of certain diseases, such as cancer.

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  • 43. 

    Which of the following is normally treated by antifungal creams and solutions?  

    • A.

      systemic mycoses 


    • B.

      superficial mycoses 


    • C.

      Subcutaneous mycoses 


    • D.

      Intramuscular mycoses

    Correct Answer
    B. superficial mycoses 

    Explanation
    Antifungal creams and solutions are typically used to treat superficial mycoses. Superficial mycoses are fungal infections that affect the outer layers of the skin, hair, and nails. They are usually not serious and can be treated with topical antifungal medications. Systemic mycoses, subcutaneous mycoses, and intramuscular mycoses are fungal infections that affect deeper tissues and organs, and they typically require systemic antifungal medications or other treatments.

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  • 44. 

    The treatment for pneumonia caused by Pneumocystis jiroveci in AIDS patients is  

    • A.

      Atovaquone

    • B.

      Miconazole

    • C.

      Pentamidine

    • D.

      Either atovaquone or pentamidine

    Correct Answer
    D. Either atovaquone or pentamidine
    Explanation
    The treatment for pneumonia caused by Pneumocystis jiroveci in AIDS patients can be either atovaquone or pentamidine. Both medications are effective in treating this type of pneumonia and can be used depending on the patient's specific circumstances and medical history. Atovaquone is an antiparasitic medication that works by inhibiting the growth of the Pneumocystis jiroveci fungus. Pentamidine is an antimicrobial agent that can be administered through inhalation or injection to treat the infection. The choice between the two drugs will depend on factors such as the patient's overall health, drug interactions, and potential side effects.

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  • 45. 

    ______________ ________________ from Streptomyces spp. binds to the sterols in fungal membranes, disrupting membrane permeability and causing leakage of cell constituents.  (2 words)  

    Correct Answer
    Amphotericin B
    Explanation
    Amphotericin B is a compound produced by Streptomyces spp. that binds to sterols in fungal membranes. This binding disrupts the permeability of the membrane, leading to leakage of cellular constituents.

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  • 46. 

    Treatment of fungal infections is more difficult than treatment of bacterial infections because the greater metabolic similarity between the fungi and their hosts limits the ability of a drug to have a selective toxicity.  

    • A.

      True

    • B.

      False

    Correct Answer
    A. True
    Explanation
    Fungal infections are more difficult to treat compared to bacterial infections because fungi have a greater metabolic similarity to their hosts. This similarity limits the effectiveness of drugs in targeting the fungi without causing harm to the host. In contrast, bacterial infections can be treated with antibiotics that specifically target the unique metabolic pathways of bacteria, allowing for more selective toxicity. Therefore, the statement that treatment of fungal infections is more difficult than treatment of bacterial infections is true.

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  • 47. 

    A neuraminidase inhibitor called __________ is sometimes used in the treatment of people infected with influenza viruses.  

    Correct Answer
    tamiflu
    Explanation
    Tamiflu is a neuraminidase inhibitor that is used in the treatment of people infected with influenza viruses. Neuraminidase is an enzyme that helps the virus to spread and replicate in the body. By inhibiting this enzyme, Tamiflu can help to reduce the severity and duration of influenza symptoms. It is most effective when taken within 48 hours of the onset of symptoms.

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  • 48. 

    Which of the following is sometimes useful against viral infections?  

    • A.

      Trimethoprim

    • B.

      Streptomycin

    • C.

      Zidovudine

    • D.

      Rifampin

    Correct Answer
    C. Zidovudine
    Explanation
    Zidovudine is sometimes useful against viral infections, specifically against HIV. It is a nucleoside reverse transcriptase inhibitor (NRTI) that works by inhibiting the reverse transcriptase enzyme, which is essential for the replication of the HIV virus. By inhibiting this enzyme, zidovudine can help slow down the progression of HIV infection and reduce the viral load in the body. However, it is important to note that zidovudine is not effective against all viral infections, but specifically against HIV.

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  • 49. 

    Which of the following is the major reason why it has been difficult to treat viral infections with chemotherapeutic agents?  

    • A.

      Viral metabolism resembles that of their hosts so there is no selective point of attack. 


    • B.

      Viruses use the metabolic machinery of their hosts, which limits many of the potential points of attack.

    • C.

      Viruses have no metabolism and therefore offer no selective point of attack.

    • D.

      Actually, viruses are not difficult to treat with chemotherapeutic agents.

    Correct Answer
    B. Viruses use the metabolic machinery of their hosts, which limits many of the potential points of attack.
    Explanation
    Viral infections are difficult to treat with chemotherapeutic agents because viruses use the metabolic machinery of their hosts. This means that the viruses rely on the host's cellular processes for replication and survival. As a result, there are limited points of attack for chemotherapeutic agents to target specifically the virus without harming the host. This makes it challenging to develop effective treatments that can selectively destroy the virus without causing significant harm to the host cells.

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  • 50. 

    ________ and ________ can be used to prevent influenza A infections, reducing the incidence of influenza by 50 to 70% in an exposed population.  (answer, answer)  

    Correct Answer
    amantadine, rimantadine
    rimantadine, amantadine
    Explanation
    Amantadine and rimantadine are both antiviral medications that can be used to prevent influenza A infections. When used in an exposed population, they have been shown to reduce the incidence of influenza by 50 to 70%.

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