Lecture 10 + 11

Question 1

phases of a growth curve

Answer 1

-lag, log/exponential, stationary, death/decline

Question 2

turbidity estimates

Answer 2

percent light transmitted depends on scattered light not reaching detector

Question 3

plates with ….. colonies are a good dilution to calculate number of cells

Answer 3

25-250

Question 4

backwards through serial dilution

Answer 4

-count colony
-divide by volume PLATED
=cfu/mL
-multiply by volume of TUBE
=cfu/tube
-divide by volume placed in that tube from previous
=cfu/mL of previous tube

Question 5

serial dilution counting

Answer 5

indirect, viable

Question 6

counting chamber

Answer 6

direct, total (count cells, but not LIVE cells)

Question 7

antibiotic

Answer 7

something that kills bacteria selectively without killing others

Question 8

bactericidal/bacteriolytic

Answer 8

death of bacteria

Question 9

bacteriostatic

Answer 9

block division

Question 10

mechanism of action

Answer 10

what is the target

Question 11

spectrum of activity

Answer 11

narrow/broad (the closer an organism is to us, the harder it is to treat as drugs must be more specific)

Question 12

effective dose

Answer 12

conc. to see bacterial inhibition

Question 13

toxic dose

Answer 13

conc. where you get damaged

Question 14

therapeutic index

Answer 14

toxic over effective

Question 15

natural

Answer 15

not modified in any way

Question 16

semi-synthetic

Answer 16

natural and modified slightly

Question 17

synthetic

Answer 17

not naturally occurring

Question 18

antibiotic sources

Answer 18

bacteria and fungi (best are soil dwellers)

Question 19

cell wall inhibitors (lytic)

Answer 19

penicillins and cephalosporins

Question 20

cell wall inhibitors come in….. forms

Answer 20

natural and semi-synthetic forms

Question 21

all cell wall inhibitors contain

Answer 21

Beta-lactam ring

Question 22

Natural penicillin works only against

Answer 22

gram +

Question 23

semisynthetic modifications

Answer 23

• make it more resistant to acid breakdown
• make it more stable
• broaden activity spectrum

Question 24

protein synthesis inhibitors (static)

Answer 24

interfere with the ribosome/mRNA/tRNA complex

Question 25

plasma membrane damaging

Answer 25

-polymyxins and daptomycin

Question 26

polymyxisns

Answer 26

damage gram neg membranes

Question 27

daptomycin

Answer 27

depolarizes gram pos membranes

Question 28

polysporin

Answer 28

make a valuable topical antibiotic despite low usefulness as systemic drug

Question 29

nucleic acid synthesis inhibitors

Answer 29

rifamycin/rifampin and quinilones

Question 30

rifamucin

Answer 30

- inhibits mRNA synthesis | - highly permeable into cells and through cell walls

Question 31

quinilones

Answer 31

inhibit DNA gyrase in DNA replication | -ciprofloxin is most well known

Question 32

metabolic inhibitors

Answer 32

sulfa drugs - synthetic - WWII soldiers spread on wounds to prevent gangrene - inhibits enzyme needed to generate folic acid

Question 33

folic acid

Answer 33

used to produce thymine and uracil

Question 34

humans are ________ to synthesize folic acid

Answer 34

unable

Question 35

sensitivity testing

Answer 35

-disk diffusion and epsilometer tests

Question 36

disk diffusion assays

Answer 36

determine what drugs are useful against bacteria

Question 37

epsilometer test (E test)

Answer 37

use a strip of antibiotic to determine a therapeutic dose

Question 38

MIC

Answer 38

minimal inhibitory concentration

Question 39

Misuse of antibiotics accelerate ...

Answer 39

the development of resistance

Question 40

modes of resistance

Answer 40

- drug modification/destruction - pathway protection - target alteration - rapid efflux - alternative pathways

Question 41

pathway protection

Answer 41

synthesis of false targets for tetracycline

Question 42

target alteration

Answer 42

single mutation in a ribosome to prevent binging

Question 43

rapid efflux

Answer 43

actively pumping out the antibiotic

Question 44

alternative pathways

Answer 44

folate scavenging against silva drugs

Question 45

T/F - Many species are naturally resistant, or less sensitive

Answer 45

TRUE

Question 46

What greatly decreases the chance of developing drug resistance?

Answer 46

using a combination of drugs, directly combating resistance, withholding newer antibiotics