Section 7

Question 1

What is an antiseptic?

Answer 1

used to treat severe infections in the 1800s
damaging to human tissue

Question 1

What did Alexander Fleming do?

Answer 1

discovered penicillin

Question 2

What was the antiseptic dilemma?

Answer 2

most casualties of war resulted from infections and treatments given after the battles

Question 3

What is Paul Ehrlich’s magic bullet hypothesis?

Answer 3

certain chemicals could selectively bind to specific bacteria

Question 4

What is the zone of inhibition?

Answer 4

circular area around spot of antibiotic where bacteria colonies don’t grow

Question 5

What can penicillin inhibit and leave unharmed?

Answer 5

inhibits growth of gram-positive bacteria
leaves eukaryotic cells unharmed

Question 6

What are characteristics of antibiotics?

Answer 6

1) therapeutic agents
2) selectively toxic towards microbes
3) generally antibacterial
4) small molecules (secondary metabolites)
5) originally referred to compounds produced by microorganisms, but today term is used for synthetic antimicrobials

Question 7

What are β-lactams?

Answer 7

class of antibiotics

Question 8

What kind of ring structure do β-lactams have?

Answer 8

4-member ring structure

Question 9

What do 4-member ring structures do?

Answer 9

enables β-lactams to inhibit bacterial cell wall synthesis

Question 10

What is an antibiotic?

Answer 10

any small molecule produced by a microbe that kills or inhibits growth of other microbes

Question 11

What are streptomyces?

Answer 11

most prolific antibiotic producer that contains “silent” pathways

Question 12

What are “silent” pathways?

Answer 12

genes that aren’t expressed under lab conditions

Question 13

What are biosynthesis pathways?

Answer 13

chemical reactions catalyzed by enzymes within a cell

Question 14

What 3 amino acids is penicillin a product of?

Answer 14

cysteine
valine
α-aminoadipate

Question 15

What is the mode of action?

Answer 15

biochemical interaction that allows antibiotic to have inhibitory effect

Question 16

What is the cell wall composed of?

Answer 16

polysaccharides peptide-peptidoglycan

Question 17

What does peptidoglycan do?

Answer 17

protects bacteria from forces in the environment

Question 18

What is gram-positive?

Answer 18

bacteria have thick peptidoglycan layer exposed to environment

Question 19

What is gram-negative?

Answer 19

bacteria have thin peptidoglycan layer in between cytoplasmic membrane and other membrane

Question 20

What are the 3 main ribosomal sites?

Answer 20

1) macrolides (E site)
2) aminoglycosides (A site)
3) P site

Question 21

What are the 2 mechanisms bacteria do to resist an antibiotic?

Answer 21

1) random mutation in normal gene
2) may acquire preexisting resistance gene from another bacterium