Antibiotic Mechanism

Question 1

Beta-lactams

Answer 1

Attach to penicillin binding protein (enzyme)

Inhibit transpeptidation enzyme which cross-links peptide chains - precursors accumulate

Question 2

Glycopeptides

Answer 2

Inhibit peptidoglycan synthesis
Bind to D-ala-D-alanine
Prevent addition of new units

Question 3

Lipopeptides

Answer 3

Disrupt bacterial cell membrane function

Hydrophobic portion inserts into membrane

Question 4

Oxazolidinones

Answer 4

Binds to 23sRNA

Prevents merging of 50 + 30

Question 5

Tetracyclines

Answer 5

Competes with tRNA acceptor
Bind to 30s
inhibits binding of new AA

Question 6

Chloramphenicol

Answer 6

Binds to 50s

Inhibits peptidyl transferase - inhibits peptide bond formation

Question 7

Aminoglycosides

Answer 7

Irreversibly bind to 30s & 16s rRNA
Block translocation from A to P
Causes misreading
Non-functional / toxic peptides accumulate

Question 8

Macrolides

Answer 8

Bind to 50s

Prevents tRNA binding

Question 9

Lincosamides

Answer 9

Bind to 50s

Prevents tRNA binding

Question 10

Fluoroquinolones

Answer 10

Inhibit topoisomerase II & IV

Prevents supercoiling

Question 11

Nitromidazoles

Answer 11

Disrupt helical structure of DNA

Question 12

Sulphonamides

Answer 12

Inhibit dihydropteroate synthase

Inhibits folate synthesis

Question 13

Trimethoprim

Answer 13

Binds to dihydrofolate synthase

Inhibits folate synthesis