Lecture 6

Question 1

Sterilization

Answer 1

killing all microorganism

Question 2

Growth Inhibition

Answer 2

disinfection (inanimate surface) and antisepsis (surfaces of living tissues)

Question 3

Heat sterilization

Answer 3

effect: denatures macromolecules & lose structure and function

Question 4

Decimal reduction time (D)

Answer 4

from heat sterilization
amount of time to reduct population by 10%
Increase temp = decrease D

Question 5

Thermal death time

Answer 5

from heat sterilization
how much heat and time it takes to kill things

Question 6

Autoclave

Answer 6

sealed heating device
steam under high pressure (cell penetration power and reduces resistance of spores)
reaches 121C
variable time 10-15 min

Question 7

Flash pasteurization

Answer 7

does not kill all microbes, but reduces their number
is rapid heating (71C, 15 sec) and rapid cooling (4C)
extends shelf life

Question 8

UV radiation

Answer 8

exposure to UV waves
energy that modifies or breaks DNA
adv: practical and safer
dis: skin exposure cancerous and high levels UV shatters DNA; surface sterilization only, cannot penetrate solid objects

Question 9

Ionizing radiation

Answer 9

exposure to electromagnetic radiation and radiation particles create radicals
radicals that disrupt proteins and lipids (shred the interior of the cell)
adv: cold sterilization & penetrates solids and liquids
dis: dangerous, requires special equipment

Question 10

HEPA filters

Answer 10

are depth filters
borosilicate (glass) fibers
microbes trapped in fiber network
removes 99.97% of 0.3um particles

Question 11

Membrane filters

Answer 11

strong polymers (e.g. cellulose)
microbes trapped on surface

Question 12

Nucleopore filters

Answer 12

polycarbonate film
microbes trapped on surface

Question 13

Antimicrobial agent

Answer 13

chemical that kills or inhibits microbial growth
classified by target organism (bacterio-, fungi-, and viri-) and action (-static, -cidal, and -lytic)

Question 14

Bacterio/fungi/viri- static

Answer 14

stop growth
binds to ribosomes
prevents protein synthesis
ex streptomycin

Question 15

Bacterio/fungi/viri- cidal

Answer 15

kills cells
cells dead but intact
bind to specific cellular targets
ex. formaldehyde

Question 16

Bacterio/fungi/viri- lytic

Answer 16

kills cells
cells lyse and are destroyed target cell wall and membranes
ex. lysozyme

Question 17

Minimum inhibitory concentration

Answer 17

amount of chemical needed to inhibit growth

Question 18

Disc diffusion technique

Answer 18

zone of inhibition

Question 19

Sterilants

Answer 19

inanimate surfaces
used in hospital and laboratory instruments
kill all microbial cells and endospores
ex. ethylene oxide (gas), formaldehyde (liquid)
applications: heat-sensitive equipment

Question 20

Disinfectants

Answer 20

inanimate surfaces
used in hospital and laboratory instruments
kills all microbial cells but not endospores
delivery through electrostatic spray
applications: airplanes and hotels

Question 21

Antiseptics (germicides)

Answer 21

hand washing and treating surface wounds
kill microbial cells or inhibit growth (non-toxic)
ex. ethanol and iodine (liquids)

Question 22

Antimicrobial drugs

Answer 22

kill and inhibit growth inside the human body
classes: structure, function, and spectrum (how broad is the drug?)
categories: synthetic and natural

Question 23

filter sterilization

Answer 23

effect: sterilization without heat and filters exclude passage of microbes
adv: useful for heat-sensitive items and very safe
dis: limited applications (liquid and gas)

Question 24

Selective toxicity

Answer 24

Paul Ehrlich’s “magic bullet”
introduce something to the body to kill pathogens but not harm the body

Question 25

Synthetic Drugs

Answer 25

selective toxicity and Paul Ehrlich

Question 26

Sulfa drugs

Answer 26

are broad spectrum; affect gram +/- bacteria
mechanism: interfere with folic acid
folic acid is precursor to DNA (FA-> nucleic acids-> DNA)

Question 27

Quinolones drugs

Answer 27

are broad spectrum; Mechanism: interfere with DNA Gyrase
Spectrum: gram +/-
synthetic

Question 28

Isoniazid drugs

Answer 28

narrow spectrum
Mechanism: interfere with mycotlic acid -> component of cell wall in mycobacterium

Question 29

Natural drugs

Answer 29

took thousands of years to develop
“tailored” by natural selection

Question 30

Antibiotics

Answer 30

produced by microorganism
thousands known, 1% useful (selective toxicity)

Question 31

Semi-synthetic

Answer 31

artificially modified antibiotics (enhances efficiency of antibiotic)

Question 32

beta-lacatam

Answer 32

mechanism: interfere with cell wall
prevent peptidoglycan synthesis
spectrum: gram +/- and intracellular
ex. penicillin (accounts for 1/2 of all antibiotics used in medical setting) is produced by fungi & there are semi-synthetic penicillin’s

Question 33

macrolids

Answer 33

mechanism: interfere with protein synthesis
binds to 50S subunit of ribosome
spectrum: gram +/-
ex. Erythromycin which is produced by bacteria

Question 34

anti-viral drugs

Answer 34

have to target something that is not in human body bc antiviral drugs can also affect host cells
ex Azidothymidine (AZT)

Question 35

anti-fungal drugs

Answer 35

fungi being eukaryotic organisms leads to anti-fungals can affect host cells
have to be fungi specific or topical
Ex. Ergosterol targets components of cytoplasmic membrane and replaces cholesterol found in animals

Question 36

antibiotic resistance mechanisms

Answer 36

impermeability, efflux, inactivation, mutation in target, absence of target
and alternative of biochemical pathway

Question 37

drug discover

Answer 37

new analogs, computer design
natural products
drug combinations
bacteriophages

Question 38

Azidothymidine (AZT)

Answer 38

resembles Thymidine (T)
HIV treatment
nucleoside analog resemble nucleotides but prevent reverse transcription