chapter 10
What is meant by selective toxicity?
Chemotherapeutic agents should act against the pathogen and not the host.
Quinolones and fluoroquinolones act against what bacterial target?
DNA gyrase
Membrane transport proteins are required for which mode(s) of antibiotic resistance?
Efflux pumps, beta-lactamases, and modification of porins all utilize membrane transport proteins.
Why are chemotherapeutic agents that work on the peptidoglycan cell wall of bacteria a good choice of drug?
Humans and other animal hosts lack peptidoglycan cell walls.
Why is polymyxin only used on the skin?
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.
Bacteria that are resistant to sulfonamide have enzymes that have a greater affinity for what? PABA Sulfonamide Tetrahyrdrofolic acid Tetracycline
PABA
Which antibiotic is overcome by beta-lactamases?
Penicillin
How might efflux pumps increase antibiotic resistance in bacteria?
Resistant bacteria can have more efflux pumps, and can have less specific efflux pumps.
Which of the following mutations would not result in antibiotic resistance? Missense mutation Nonsense mutation Silent mutation Frameshift insertion Frameshift deletion
Silent mutation
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.
The bacterium is neither killed nor inhibited by the antibiotic.
Why is it difficult to find good chemotherapeutic agents against viruses? There is no effective way to deliver the drug to the virus. Viruses infect both bacteria and human cells. Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host cell unaffected. Viruses are not cells, and therefore not sensitive to such compounds.
Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host cell unaffected.
Why would an efflux pump for penicillin located on a bacterial cell membrane not be effective at providing resistance to the drug?
Why would an efflux pump for penicillin located on a bacterial cell membrane not be effective at providing resistance to the drug?
R-plasmids are most likely acquired via
bacterial conjugation.
Certain cancer cells have ABC transport molecules at the cell surface. These transporters use energy from ATP to move chemotherapeutic agents out of the cell. Which of the following do you think these transporters are most closely related to?
membrane pumps
A researcher creates an antibiotic that binds to a protein present only on B. anthracis (the causative agent of anthrax), lysing the cell from the outside. After a couple of years using this antibiotic, some resistant organisms are found. Which of the following best outlines the mechanism for development of this resistance?
mutation in B. anthracis → altered target → resistant bacterium
A new bacterial molecule is discovered. This molecule binds to an antibiotic and facilitates the binding of a phosphate group, thus inactivating the antibiotic. Which category best describes the mechanism of antibiotic resistance conferred by this molecule? bacterial enzymes altered porins rapid efflux of the antibiotic conjugation
rapid efflux of the antibiotic?
When a patient is treated with antibiotics, __________. mutations occur in all of the bacterial cells sensitive bacterial cells multiply uncontrollably the drug will kill or inhibit the growth of all of the sensitive bacterial cells the drug will kill or inhibit the growth of all of the resistant bacterial cells mutations will occur in the sensitive bacterial cells, but not in the resistant bacterial cells
the drug will kill or inhibit the growth of all of the sensitive bacterial cells
The process of acquiring antibiotic resistance by means of bacteriophage activity is called
transduction
