Bacterial Structure, Function, and Growth

Question 1

B-lactams

Answer 1

penicillins, cepalosporins

inhibit final transpeptidation reaction in cross linking of peptidolycan

Question 2

vancomycin

Answer 2

inhibits utilization of lipid linked intermediate at an intermediate step in peptidoglycan synthesis (like elongation of peptidoglycan chain)

Question 3

cycoserine

Answer 3

inhibits alanine racemase, preventing formation of muramyl pentapeptide, an early intermediate in peptidoglycan synthesis

Question 4

outer and cytoplasmic membrane active antimicrobials: polymyxins

Answer 4

cationic surfactants that disrupt bacterial outer and cytoplasmic membranes; less active on mammalian cell membranes

Question 5

inhibitors of protein synthesis at the ribosomal level

Answer 5

selective toxicity is due to differences between bacterial and mamilian ribosomes

Question 6

aminoglycosides

Answer 6

streptomycin, kanamycin, gentamycin, neomycin, tobramycin, amikacin

bind to specific target proteins to the 30s ribosomal subunit and inhibit protein synthesis

Question 7

tetracyclines

Answer 7

reversibly bind to the 30 s ribosomal subunit and inhibit binding of aminoacyl tRNA

Question 8

Chloramphenicol

Answer 8

binds reversibly to 50S ribosomal subunit and inhibits peptidyl transferase and pepond formationtide b

Question 9

macrolides and lincomycins

Answer 9

erythromycin, linocomycin, and clindamycin

bind to 23s ribosomal rna of the 50s subunit and inhibit peptidyl transferase

Question 10

quinolones

Answer 10

inhibit dna gyrase and topoisomerase and therefore interfere with DNA replication

Question 11

rifampicin

Answer 11

inhibits RNA polymerase and interferes with the initiation of transcription

Question 12

sulfonamides

Answer 12

structures of PABA which is components of folic acid
inhibit formation of folic acid by competing with PABA

bacteria specifically possess enzymes for making folic acid not humans

Question 13

trimethoprim

Answer 13

interferes with folate metabolism by inhibiting dihydrofolate reductase

50,000 fold greater sensitivity of bacterial enzyme to the drug

Question 14

isoniazin

Answer 14

inhibits lipid synthesis (maybe mycolic acid synthesis) in susceptible mycobacteria

Question 15

metronidazole

Answer 15

specifically interferes with anaerobic metabolism