Ch. 10 Mastering Microbio

25 July 2022
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question
An antimicrobial that inhibits cell wall synthesis will result in which of the following? Cells become more susceptible to osmotic pressure. Cells cannot attach to their hosts. The sterols in the cell wall become nonfunctional. Ribosomes lose their function. The replication of cells, including cancer cells, slows down.
answer
cells become more susceptible to osmotic pressure
question
Beta-lactam antibiotics have an effect on which of the following types of cells? animal cells virus-infected cells bacterial cells fungal cells both animal and fungal cells
answer
bacterial cells (think beta-bacterial)
question
Most drugs that inhibit the synthesis of the cell wall act by preventing the formation of alanine-alanine bridges. preventing the cross-linkage of NAM subunits. preventing the formation of ฮฒ-lactamases. blocking the secretion of cell wall molecules from the cytoplasm. disrupting the formation of the mycolic acid layer of the cell wall.
answer
Preventing the cross-linkage of NAM subunits
question
Which of the following statements is true of selective toxicity? Selective toxicity takes advantage of metabolic differences between host and pathogen. Selective toxicity takes advantage of structural differences between host and pathogen. Selective toxicity takes advantage of structural and/or metabolic differences between host and pathogen. Antimicrobial agents must target structural differences between host and pathogen and be more toxic to the patient than the pathogen. To be effective, an antimicrobial agent must be more toxic to the patient than the pathogen.
answer
Selective toxicity takes advantage of structural and/or metabolic differences between host and pathogen
question
The mechanism of action of the antibiotic vancomycin is disruption of cytoplasmic membranes. inhibition of cell wall synthesis. inhibition of a metabolic pathway. inhibition of protein synthesis. inhibition of nucleic acid synthesis.
answer
inhibition of cell wall synthesis
question
Why do the beta-lactam drugs affect bacteria but NOT human cells? The beta-lactam antibiotics act on bacterial cell walls; human cells do not have cell walls. Beta-lactam antibiotics attack bacterial DNA and do not affect human DNA. The mechanism of action for beta-lactam drugs inhibits protein synthesis, and bacteria that do not require proteins are automatically resistant. Beta-lactam antibiotics are destroyed by human enzymes that limit the drug's action.
answer
The beta-lactam antibiotics act on bacterial cell walls; human cells do not have cell walls
question
Why is polymyxin only used on the skin? It can disrupt the metabolic pathways found in humans. It has no effect on bacteria that live in the GI tract. 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. It is sensitive to degradation by acid, making oral delivery unsuitable.
answer
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
question
ฮฒ-lactamase production is an example of which of the following types of resistance? alteration of the target of the drug overproduction of an enzyme in a key metabolic pathway change in the permeability of the drug inactivation of the drug removal of the drug via a pump
answer
inactivation of the drug
question
Drug-resistant populations of microbes arise when synergy between medications occurs. exposure to drugs causes mutations that produce resistance. the patient becomes immune to the drug. exposure to drugs selectively kills sensitive cells, allowing overgrowth of resistant cells. resistant cells become numerous in a population due to their greater vigor.
answer
exposure to drugs selectively kills sensitive cells, allowing overgrowth of resistant cells
question
Which of the following activities can be shown to increase resistance among microbial populations? taking an antimicrobial drug for the entire prescribed time taking a combination of antimicrobial drugs developing second- and third-generation versions of antimicrobial drugs taking antibacterial drugs for viral infections
answer
taking antibacterial drugs for viral infections
question
What is meant when a bacterium is said to become "resistant" to an antibiotic? The antibiotic kills or inhibits the bacterium. The antibiotic is metabolized by the bacterium, providing more energy for growth of the cell. The bacterium is neither killed nor inhibited by the antibiotic. The antibiotic mutates in a way that benefits the bacterium.
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the bacterium is neither killed nor inhibited by the antibiotic
question
The process of acquiring antibiotic resistance by means of bacteriophage activity is called transduction. R-plasmid acquisition. point mutation. transformation.
answer
transduction
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R-plasmids are most likely acquired via (select all that apply) transduction. bacterial conjugation. transformation. translation.
answer
bacterial conjugation