Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
18 Cards in this Set
- Front
- Back
|
what is the general structure for penicillin
|
5 member thiazolidine ring joined by B-lactam ring which is attached to a side chain
|
|
|
How does penicillin work
|
inhibition of the last step of cell wall synthesis
transpeptidation rxn results in cross-linking of adj peptidoglycan strands |
|
|
mechanism for penicillin
|
B-lactam binds to protein preventing polymerization
Releases lysin to degrade previous peptidoglycan Splitting of B-lactam results in INACTIVE product |
|
|
what is structure of cephalosporins
|
6-member dihydrothiazine ring joined to B-lactam ring
|
|
|
What is the difference between penicillin and cephalosporin
|
cephalosporin: 6 member ring, more resilient to B-lactamase
|
|
|
B-lactamase inhibitors
example of... |
expand the spectrum of B-lactam antibiotics
example: clavulanic acid |
|
|
how does glycopeptide antibiotics work
example of... |
inhibit the use of lipid-linked cell wall intermediates in the assembly of linear PG molecules
Used for multi-resistant organisms Vancomycin |
|
|
bacitracin is used on what wall type
how does it work |
Gram Pos.
targets lipid carrier responsible for moving PG precursors through cytoplasmic membrane to cell wall |
|
|
polymyxin is used on what wall type
how does it work |
Gram Neg.
FA bind to hydrophobic portion of the OUTER membrane. interacts with LPS and phospholipids...INCREASE CELL PERMEABILITY |
|
|
What are the antibiotics that target the cell wall??
|
penicillin
cephalosporin b-lactamase glycopeptide antibodies bacitracin (gram pos) polymyxin (gram neg) |
|
|
what are the antibiotics that inhibit NUCLEIC ACID SYN.
|
quinolones
novobiocin rifamycin metronidazole |
|
|
how does QUINOLONES work
|
inhibition of DNA replication
binds to DNA gyrase, prevent supercoiling DNA gyrase: introduce negative superhelical turns into covalently circular DNA |
|
|
how does novobiocin work
|
also inhibit DNA gyrase
bactericidal for a variety of bacteria...ESPECIALLY GRAM POS |
|
|
how does metronidazole work
|
reduced form acts as a free radical that damages bacterial DNA.
|
|
|
what antibiotics inhibits PROTEIN SYN.
|
aminoglycosides
tetracyclins Macrolides clindamycin streptogramin |
|
|
how does aminoglycosides work
|
binds to 30S ribosomal protein
result: misread of mRNA premature release of ribosome from mRNA |
|
|
how does tetracyclines work
|
binds to 30S subunits and block binding of aminoacyl-transfer RNA @ A site
|
|
|
how does macroclides work
|
binds to 50S ribosomal subunits and block polypeptide elongation.
BACTERIOSTATIC |
