Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

SP14 Microbiology > EX2 Effects of Antibiotics on Bacteria - Bailey > Flashcards

EX2 Effects of Antibiotics on Bacteria - Bailey Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

In 1920, Alexander Flemming described the potential usefulness of what

A

penicillin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

In 1940, Ernst Chain and Howard Flory demonstrated the water and effectiveness of penicillins in what

A

humans (in WWII)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the two mode of action of antibiotics

A

bactericidal; kill bacteria

bacteriostatic; reduce metabolic activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

An ideal antibiotic has what four things

A

broad spectrum of activity
would not induce resistance
high therapeutic index
selective toxicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

This is the ratio between a toxic dose and effective dose; if the ratio is 1, then you need a toxic dose to eradicate the microbe

A

high therapeutic index

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What four things are unique to microbes that help achieve selective toxicity

A

cell wall
enzymes for replication, transcription, and translation
essential metabolites
ribosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the 5 ways that antibiotics inhibit bacteria

A 
cell wall synthesis
membrane function
protein synthesis (ribosomes)
antimetabolites
inhibition of nucleic acids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are some places of antibiotic inhibition involving cell wall synthesis

A 
NAG binding with NAM
NAG/NAM elongtation
formation of NAM side chains
transport of chain to periplasmic space
peptide chain cross linking
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does penicillin disrupt cell wall synthesis

A

prevents the formation of peptide bonds between side chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What structure does penicillin use to disrupt cell wall synthesis

A

D-alanine; penicillin is cleaved instead of the D-alanine causing substrate overload, and cleaved penicillin is more toxic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is used to disrupt cell membrane function

A

polymyxin B sulfate by binding to LPS layer, disrupting it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is targeted in inhibiting protein synthesis

A

ribosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are some of the places of antibiotic inhibition involving ribosomes

A

prevention of 50S and 30S binding
prevention of tRNAs to bring AAs to 30S
change configuration of ribosome to change the tunnel
prevent 30S and 50S from binding to mRNA start site
prevent elongation of AA chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What can be an issue with inhibitors of DNA replication

A

they bind to DNA are are too toxic too use

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the one antibiotic that binds to DNA, being covered to an active from by anaerobic microbes

A

metronidazole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Antibiotics like nalidxic acid and quinolines affect what

A

DNA gyrase

17
Q

Antibiotics like rifamycin inhibit this

A

RNA polymerase

18
Q

Hows does sulfanilamide act as a antimetabolite

A

PABA (para-aminobenzoic acid) forms folic acid in bacteria, and the sulfanilamide disrupts the formation

19
Q

Penicilin, clindamycin, and cephalosporins are typically used to treat what

A 
odontogenic infections
(clindamycin also treats abscesses)
20
Q

metronidazole and tetracyclines are typically used to treat what

A

peridontitis (metronidazole also treats abscesses)

21
Q

What are the three steps in the action of antibiotics

A

drug penetrates the envelope
transport into cell
drug binds to target

22
Q

What are the three mechanisms of drug resistance

A

synthesis of enzymes that inactivate the drug
prevent of access to the target site
modification of the target site

23
Q

What are the two ways in which a bacteria can prevent an antibiotic form accessing the target site

A

inhibiting uptake

increasing secretion of the drug

24
Q

Some bacteria can produce enzymes which do what to penicillin

A

break the β-lactam ring; inactivating the bond

25
Q

How to antibiotics enter the cell

A

through porins

26
Q

Bacteria change the structure of porins, which increase the resistance to which antibiotics

A

tetracyclines and quinolones

27
Q

Some bacteria develop this to remove antibiotics from themselves (all classes of bacteria have this

A

efflux pumps; pump the drug out

28
Q

How does a microbe modify the target site

A

modify enzyme activity

alteration of metabolic pathway (high affinity, etc.)

29
Q

How does antibiotic resistance spread

A

chromosome associated resistance (mutations)
plasmid mediated resistance
rapid spread resistance

30
Q

What is the main reason it is important to finish the course of an antiobiotic

A

high resistant bacteria take a longer time to die, if you stop taking the antibiotic prematurely, then the number of antibiotic resistant bacteria increases

31
Q

What three things are used to combat an antibiotic resistant pathogen

A

synergism (2+ antibiotics)
antagonism
indifference

32
Q

What are the drawbacks to administering an antibiotic cocktail

A 
failure to eliminate pathogen; superinfection
synergistic toxicity (multiplied)
33
Q

True or False

Antibiotics are effective against all microbes

A

False; not viruses, fungi, etc.

SP14 Microbiology (31 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions