bio170 ch. 10 – Flashcards
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Any drug that acts against a disease is called a(n) (analog/antibiotic/chemotherapeutic) agent.
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chemotherapeutic
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A compound is extracted from a microbial culture and is modified in the laboratory for use as an oral medication. This product would be a(n) A. analog. B. synthetic antimicrobial. C. semisynthetic antimicrobial. D. probiotic. E. antibiotic.
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C. semisynthetic antimicrobial.
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What is meant by selective toxicity? A. Chemotherapeutic agents should work on certain types of pathogens. B. Chemotherapeutic agents should act against the pathogen and not the host. C. Chemotherapeutic agents should have only one mode of action. D. Chemotherapeutic agents should work on many different targets on a pathogen.
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B. Chemotherapeutic agents should act against the pathogen and not the host.
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Why are chemotherapeutic agents that work on the peptidoglycan cell wall of bacteria a good choice of drug? A. Humans and other animal hosts lack peptidoglycan cell walls. B. Bacteria are especially sensitive to these compounds. C. They are less expensive that other chemotherapeutic agents. D. The drugs also work against DNA gyrase.
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A. Humans and other animal hosts lack peptidoglycan cell walls.
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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 is sensitive to degradation by acid, making oral delivery unsuitable. C. It can disrupt the metabolic pathways found in humans. D. It has no effect on bacteria that live in the GI tract.
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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.
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Quinolones and fluoroquinolones act against what bacterial target? A. Bacterial ribosomes B. Cell membranes C. DNA gyrase D. Cell walls E. Metabolic pathways unique to bacteria
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C. DNA gyrase
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Why is it difficult to find good chemotherapeutic agents against viruses? A. There is no effective way to deliver the drug to the virus. B. Viruses infect both bacteria and human cells. C. Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host cell unaffected. D. Viruses are not cells, and therefore not sensitive to such compounds.
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C. Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host cell unaffected.
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Selective (toxicity/action/treatment) means that a given antimicrobial agent is more toxic to a pathogen than to the host being treated.
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toxicity
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An antimicrobial that inhibits cell wall synthesis will result in which of the following? A. The sterols in the cell wall become nonfunctional. B. The replication of cells, including cancer cells, slows down. C. Cells become more susceptible to osmotic pressure. D. Ribosomes lose their function. E. Cells cannot attach to their hosts.
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C. Cells become more susceptible to osmotic pressure.
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Beta-lactam antibiotics have an effect on which of the following types of cells? A. animal cells B. virus-infected cells C. bacterial cells D. fungal cells E. both animal and fungal cells
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C. bacterial cells
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Because all cells engage in protein synthesis, there are few antimicrobial drugs that selectively inhibit this process. True False
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False
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Which of the following antibiotics disrupts cytoplasmic membrane function? A. amphotericin B B. penicillin C. tetracycline D. erythromycin E. streptomycin
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A. amphotericin B
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Which of the following is NOT a target of drugs that inhibit protein synthesis? A. interference with alanine-alanine bridges B. the tRNA docking site C. movement of the ribosome from one codon to the next D. the shape of the 30S ribosomal subunit E. the enzymatic site of the 50S ribosomal subunit
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A. interference with alanine-alanine bridges
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Most drugs that inhibit the synthesis of the cell wall act by A. preventing the formation of alanine-alanine bridges. B. preventing the cross-linkage of NAM subunits. C. blocking the secretion of cell wall molecules from the cytoplasm. D. disrupting the formation of the mycolic acid layer of the cell wall. E. preventing the formation of β-lactamases.
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B. preventing the cross-linkage of NAM subunits.
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Which of the following drugs inhibits nucleic acid synthesis specifically in prokaryotes? A. rifampin B. tetracycline C. quinolones D. actinomycin E. 5-fluorocytosine
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C. quinolones
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Secondary infections that result from the killing of some of the normal microbiota are called (antagonism/superinfections/resistance).
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superinfections
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The outer membrane of Gram-negative bacteria enables many antimicrobial drugs to enter the cell more easily. True False
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False
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A (bacteriostatic/bacteriocidal/minimum) concentration of a drug is one at which microbes survive but are not able to grow and reproduce.
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bacteriostatic
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Organs that are commonly affected by drug toxicity include the kidneys and the liver. True False
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True
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The abbreviation (MIC/MID/MD) stands for the smallest amount of a drug that will inhibit the growth and reproduction of a pathogen. (Be sure to use all capital letters.)
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MIC
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The therapeutic range of an antimicrobial is the A. range of microorganisms the antimicrobial effects. B. ratio of the dose a patient can tolerate to the effective dose. C. ratio of the concentration of antimicrobial in the blood to the oral dose. D. range of concentrations at which the antimicrobial is both effective and non-toxic. E. length of time the medication persists in the body after a single dose.
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D. range of concentrations at which the antimicrobial is both effective and non-toxic.
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Which antibiotic is overcome by beta-lactamases? A. Tetracycline B. Sulfonamide C. Penicillin D. Tetracycline, Penicillin, and Sulfonamide are all affected by beta-lactamase.
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C. Penicillin
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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.
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E. Resistant bacteria can have more efflux pumps, and can have less specific efflux pumps.
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Bacteria that are resistant to sulfonamide have enzymes that have a greater affinity for what? A. PABA B. Sulfonamide C. Tetrahyrdrofolic acid D. Tetracycline
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A. PABA
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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.
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D. Penicillin disrupts the cell wall, which is located outside of the cell membrane.
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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 porins D. Beta-lactamases E. Modification of a metabolic enzyme
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A. Efflux pumps, beta-lactamases, and modification of porins all utilize membrane transport proteins.
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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.
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C. The bacterium is neither killed nor inhibited by the antibiotic.
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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
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C. the drug will kill or inhibit the growth of all of the sensitive bacterial cells
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The process of acquiring antibiotic resistance by means of bacteriophage activity is called A. transduction. B. R-plasmid acquisition. C. point mutation. D. transformation.
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A. transduction.
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Which of the following mutations would not result in antibiotic resistance? A. Missense mutation B. Nonsense mutation C. Silent mutation D. Frameshift insertion E. Frameshift deletion
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C. Silent mutation
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A microbe resistant to a variety of different antimicrobials is said to have (cross/drug/multiple) resistance
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multiple
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R-plasmids are extrachromosomal DNAs that contain genes for antimicrobial resistance. True False
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True
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β-lactamase production is an example of which of the following types of resistance? A. alteration of the target of the drug B. change in the permeability of the drug C. overproduction of an enzyme in a key metabolic pathway D. removal of the drug via a pump E. inactivation of the drug
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E. inactivation of the drug
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Alterations in the structure of which of the following are an important aspect of Gram-negative bacterial resistance to antimicrobial drugs? A. plasmids B. porins C. cytoplasmic membrane D. mitochondria E. ribosomes
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B. Porins
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How does resistance to drugs spread in bacterial populations? A. Exposure to drugs causes mutations in bacterial genes. B. Exposure to drugs alters gene expression in bacteria. C. Both horizontal gene transfer and the growth of biofilms spread drug resistance. D. The formation of biofilms protects bacteria from the effects of drugs. E. Horizontal gene transfer between bacteria spreads R (resistance) plasmids.
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C. Both horizontal gene transfer and the growth of biofilms spread drug resistance.
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Which of the following activities can be shown to increase resistance among microbial populations? A. taking antibacterial drugs for viral infections B. taking an antimicrobial drug for the entire prescribed time C. taking a combination of antimicrobial drugs D. developing second- and third-generation versions of antimicrobial drugs
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A. taking antibacterial drugs for viral infections
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Which of the following is NOT a possible side effect of antimicrobial therapy? A. resistance B. allergies C. toxicity D. disruption of normal microbiota
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A. resistance
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Which of the following is NOT a direct mode of action of antimicrobial drugs? A. inhibition of nucleic acid synthesis B. inhibition of protein synthesis C. inhibition of flagella formation D. inhibition of cell wall synthesis
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C. inhibition of flagella formation
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Which of the following is NOT associated with microbial mechanisms of resistance? A. denaturation of proteins B. porins C. beta-lactamases D. MfpA protein
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A. denaturation of proteins
