anti-microbials

Question 1

2 targets of bacterial synthesis

Answer 1

bacterial protein synthesis, bacterial cell wall synthesis

Question 2

what are bacteria

Answer 2

single-celled microorganisms with a cell wall and membrane; entire phylogenetic domain, but only 1/3 are pathogenic

Question 3

property of gram positive bacteria

Answer 3

prominent peptidoglycan cell wall

Question 4

example of gram positive bacteria

Answer 4

Staph. aureus

Question 5

property of gram negative bacteria

Answer 5

thin peptidoglycan cell wall with outer membrane with lipopolysaccharide (LPS)

Question 6

example of gram negative bacteria

Answer 6

E. coli

Question 7

property of mycolic bacteria

Answer 7

peptidoglycan layer with outer mycolic acid layer

Question 8

example of mycolic bacteria

Answer 8

Mycobacterium tuberculosis

Question 9

describe stages of prokaryotic protein synthesis

Answer 9

nucleic acid synthesis -> DNA replication -> RNA synthesis -> protein synthesis

Question 10

small part of pathway of nucleic acid synthesis relevant to antibiotics

Answer 10

PABA -> (DHOp synthase) dihydropteroate (DHOp) -> DHF -> (DHF reductase) tetrahydofolate (THF)

Question 11

describe what enzyme is used in DNA replication relevant to antibiotics, and what it does

Answer 11

DNA gyrase (same as topoisomerase), which releases tension

Question 12

describe what enzyme is used in RNA synthesis, and what it does

Answer 12

RNA polymerase: produces RNA from DNA template; differs from eukaryotic RNA polymerase

Question 13

describe what are used in protein synthesis, and what they do and how they differ between prokaryotes (bacteria) and eukaryotes

Answer 13

ribosomes: produce protein from RNA templates; differ from eukaryotic ribosomes (30s and 50s vs 40s and 60s)

Question 14

anti-biotic class which inhibits DHOp synthase

Answer 14

sulphonamides (although most bacteria have developed resistance)

Question 15

anti-biotic class which inhibits DNF reductase

Answer 15

trimethoprim (used in combination with sulphonamides - co-trimoxazole)

Question 16

anti-biotic class which inhibits DNA gyrase (topoisomerase)

Answer 16

fluroquinolones

Question 17

anti-biotic class which inhibits bacterial RNA polymerase

Answer 17

rifamycins (used for Mycobacterium tuberculosis)

Question 18

anti-biotic class which inhibits ribosomes

Answer 18

macrolides (e.g. erythromycin)

Question 19

3 stages of bacerial wall synthesis (dynamic process)

Answer 19

peptidoglycan synthesis -> peptidoglycan transportation -> peptidoglycan incorporation

Question 20

describe what happens in peptidoglycan synthesis (in cytoplasm)

Answer 20

pentapeptide created on NAM -> NAG associates with NAM -> forms peptidoglycan

Question 21

what transports peptidoglycan across membrane into periplasm

Answer 21

bactoprenol

Question 22

when is peptidoglycan incorporated into cell wall, and what enzyme is involved

Answer 22

when transpeptidase enzyme cross-links peptidoglycan pentapeptides

Question 23

anti-biotic class which inhibits peptidoglycan synthesis by binding to pentapeptide

Answer 23

glycopeptides (e.g. vancomycin)

Question 24

anti-biotic which inhibits bactoprenol regeneration, preventing peptidoglycan transportation

Answer 24

bacitracin (not used anymore)

Question 25

anti-biotic class which inhibits peptidoglycan incorporation into cell wall by binding covalently to transpeptidase

Answer 25

B-lactams (most important bacterial wall inhibitors)

Question 26

3 examples of B-lactams (contain B-lactam ring)

Answer 26

carbapenems, cephalosporins, penicllins

Question 27

anti-biotic class which disrupts gram +ve cell membranes

Answer 27

lipopeptide

Question 28

anti-biotic class which disrupts gram -ve cell membranes by binding to LPS

Answer 28

polymyxins