Lecture 2

Question 1

Antibiotic modes of action

Answer 1

bactericidal

bacteriostatic

Question 2

Therepudic index

Answer 2

ratio between toxic does and effective dose

If =1, then you need toxic dose to be effective

Question 3

Achieving selective toxicity

Answer 3

cell wall
enzymes
metabolites
ribosome strucutre

Question 4

5 ways antibiotics inhibit bacteria

Answer 4

cell wall synthesis
cell membrane function
protein synthesis
act as antimetabolites
nucleic acid synthesis

Question 5

How does penicillin disrupt cell wall synthesis

Answer 5

Enzyme for cleaving D-ala starts to cleave penicillin instead, also creating a toxic compound

Question 6

Polymyxin B sulfate

Answer 6

Disrupts cell membrane

Binds to phospholipids

Question 7

Linezolid

Answer 7

Prevents mature ribosome

Question 8

Tetracycline

Answer 8

Prevents tRNA binding

Question 9

Aminoglycosides

Answer 9

Kills ribosome (bacteriacidal)

Question 10

Macrolides cloramphenicol

Answer 10

Ribosome detaches from mRNA

Question 11

Metronidazole

Answer 11

converted from inert form to DNA replication inhibitor by anaerobic microbes

Question 12

Inhibition of nucleic acid synthesis

Answer 12

DNA replication inhibitors
DNA gyrase inhibitors
RNA polymerase inhibitors

Question 13

Penicillin used for

Answer 13

odontogenic infections

Question 14

Clindamycin used for

Answer 14

odontogenic infections

Question 15

Cephalosporins used for

Answer 15

odontogenic infections

Question 16

metronidazole used for

Answer 16

abcesses and periodontitis

Question 17

Tetracyclines

Answer 17

periodontitis

Question 18

Steps in action of antibiotics

Answer 18

Penetrates envelope
Transport into cell
Binds to target

Question 19

Mechanisms of drug resistance (4)

Answer 19

synthesis of enzymes that deactivate drug
Inhibit uptake
increase secretion of drug
Modification of target site

Question 20

Tetracyclin resistance

Answer 20

efflux pumps pump it out of the cell