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Flashcards in Effects of Antibiotics on Life Cycle of bacteria Deck (24)
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what is the difference b/w bactericidal and bacteriostatic

bactericdal kills all whereas bacteriostatic slows activity


what are the characteristics of an ideal antibiotic ?

broad spectrum of activity, no resistance, high therapeutic index, selective toxicity


what does a low therapeutic index mean for an antibiotic

it means it will take a toxic dose (to the host) in order to kill the bacteria


what 4 parts of bacteria should you attack to achieve selective toxicity

cell wall, unique replication/transcription enzymes, unique metabolites, ribosomes


what are the 5 main ways to inhibit bacteria

1-inhibit cell wall synthesis
2-disrupt cell membrane function
3-inhibit protein synthesis
4-inhibit nucleic acid synthesis
5-act as antimetabolite


how does penicillan act to inhibit bacteria

disrupts cell wall synthesis


what does polymyxin B sulfate do to inhibit bacteria, and what is its drawback as an antibiotic

disrupts cell membrane function, but also attacks eukaryotes so only used as a topical antibiotic


what is the most common strategy for an antibiotic to inhibit bacteria, Why ?

inhibit protein synthesis, because the bacterial ribosome is structurally different than the eukaryotic ribisome


what enzymes would an antibiotic attack if it were inhibiting nucleic acid synthesis

DNA gyrase (bacteria only have this), RNA polymerase


T/F an antibiotic trying to inhibit nucleic acid synthesis is good if it binds to DNA ?

F, do NOT want it to bind to DNA else would be toxic to host human


what specific antibiotic acts as an antimetabolite



macrolides, linezoid,tetracycline, and aminoglycosides all have what in common ?

antibiotics that block the ribosome cycle thus blocking protein synthesis


what is the main cause of bacteria to develop antibiotic resistance

selective pressure and overuse


what are the 3 steps in the action of an antibiotic to be effective

1 - penetrate the envelope
2-transport into the cell
3-bind to target


what are the 3 mechanisms of drug resistance

1-synthesis of enzymes that inactivate drug
2- prevention of access to target site
3-modificaton of target site


Beta lactamases is an example of what kind of enzyme

an enzyme bacteria have developed that inactivates penicillan (caused bacteria resistance)


bacteria developing efflux pumps to pump tetracycline out of the cell is a demonstration of what mechanism of drug resistance

preventing access to the target site


if bacteria can modify an enzymes affinity for a particular drug it is an exp of what mechanism of drug resistance

modification of the target site


what are the 3 ways antibiotic resistance can spread

1-chromosome associated resistance
2-plasmid mediated resistance
3-rapid spread of resistance


why it is so crucial to completely finish an antibiotic for the reccomended time period

Because an antibiotic will kill the most sensitive bacteria 1st, then the int. bacteria, and lastly the highly resistant bacteria (if dont finish wont kill this last group then your fucked )


3 ways to combat an antibiotic resistant pathogen

synergism, antagonism, indifference


what is the difference b/w synergism and antoagonism antibiotics

synergism uses 2 drugs to amplify effect, antagonism uses 2 but 1 is bacteriostatic and other is bactericidal


T/F antibiotics are effective against all microbes

F, do not affect virus


what are potential drawbacks of administering an antibiotic cocktail (2 or more drugs together)

-could become resistant to 2 drugs
-doesnt eliminate bacteria and get superinfection
-synergistic toxicity to host