Inhibitors of Bacterial Cell Wall Synthesis Flashcards
What property of bacteria requires a rigid cell wall to maintain integrity and shape?
high internal osmotic pressure
T/F. During growth and division, bacteria require new cell wall synthesis. Therefore, inhibitors render growing bacteria susceptible to osmotic rupture, with no effect on mammalian cells which do not contain cell walls.
True. This effect is bacteriCIDAL
T/F. BacteriCIDAL effects occur only when cells are growing.
True
___ lack cell walls and are intrinsically resistant. ___-forms of bacteria have no cell walls. There is a sanctuary in the ___ where the osmotic pressure is high.
Mycoplasma; L-forms; kidney
What is the first two steps in cell wall synthesis? What drug inhibits both steps? What condition is this same drug the second line agent?
L-ala to D-ala
linkage of two D-ala
Cycloserine, second line agent in the treatment of TB
_-___ dipeptide is linked to ___ other amino acids and _-___ acid to form a pentapeptide with a UDP-carrier + ___. What does the structure couple to?
D-ala; three; N-acetylmuramic acid; isoprene
N-acetylglucosamine
The sugar-peptide structure linked to ___-___ lipid carrier is transported to the ___ of the cell membrane.
isoprenyl-phosphate; exterior
How is the sugar-peptide added to polymer (peptidoglycan strands)?
via Peptidoglycan synthase
What binds to isoprenyl phosphate so that it can’t be used as a carrier?
Bacitracin
What prevents the transfer of sugar-pentapeptide from carrier molecule to growing peptidoglycan chain?
Vancomycin through the inhibition of Peptidoglycan synthase. It also inhibits the cross-linking of peptidoglycans
What reaction cross-links peptidoglycan strands by connecting penultimate D-Ala from one strand to a diaminopimelic acid unit in a sugar-peptide of an adjacent strand?
transpeptidation reaction
What acts by binding to various penicillin-binding proteins (PBP’s) (also known as transpeptidases) and inhibiting transpeptidation reaction?
Beta-Lactams
___ to beta-lactams is commonly associated with production of _-___, which break the ring.
Resistance; Beta-lactamases
Where are Beta-lactamases found in gram negative and gram positive bacteria?
Gram positive - outside the cell wall
Gram negative - in the periplasmic space
